On Wed, 2014-01-22 at 22:22 +0530, Srikanth Thokala wrote:
> This is the driver for the AXI Video Direct Memory Access (AXI
> VDMA) core, which is a soft Xilinx IP core that provides high-
> bandwidth direct memory access between memory and AXI4-Stream
> type video target peripherals. The core provides efficient two
> dimensional DMA operations with independent asynchronous read
> and write channel operation.
>
> This module works on Zynq (ARM Based SoC) and Microblaze platforms.
Few comments below.
>
> Signed-off-by: Srikanth Thokala <sthokal@xxxxxxxxxx>
> ---
> NOTE:
> 1. Created a separate directory 'dma/xilinx' as Xilinx has two more
> DMA IPs and we are also planning to upstream these drivers soon.
> 2. Rebased on v3.13.0-rc8
>
> Changes in v2:
> - Removed DMA Test client module from the patchset as suggested
> by Andy Shevchenko
> - Removed device-id DT property, as suggested by Arnd Bergmann
> - Properly documented DT bindings as suggested by Arnd Bergmann
> - Returning with error, if registration of DMA to node fails
> - Fixed typo errors
> - Used BIT() macro at applicable places
> - Added missing header file to the patchset
> - Changed copyright year to include 2014
> ---
> .../devicetree/bindings/dma/xilinx/xilinx_vdma.txt | 75 +
> drivers/dma/Kconfig | 14 +
> drivers/dma/Makefile | 1 +
> drivers/dma/xilinx/Makefile | 1 +
> drivers/dma/xilinx/xilinx_vdma.c | 1486 ++++++++++++++++++++
> include/linux/amba/xilinx_dma.h | 50 +
> 6 files changed, 1627 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/dma/xilinx/xilinx_vdma.txt
> create mode 100644 drivers/dma/xilinx/Makefile
> create mode 100644 drivers/dma/xilinx/xilinx_vdma.c
> create mode 100644 include/linux/amba/xilinx_dma.h
>
> diff --git a/Documentation/devicetree/bindings/dma/xilinx/xilinx_vdma.txt b/Documentation/devicetree/bindings/dma/xilinx/xilinx_vdma.txt
> new file mode 100644
> index 0000000..ab8be1a
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/dma/xilinx/xilinx_vdma.txt
> @@ -0,0 +1,75 @@
> +Xilinx AXI VDMA engine, it does transfers between memory and video devices.
> +It can be configured to have one channel or two channels. If configured
> +as two channels, one is to transmit to the video device and another is
> +to receive from the video device.
> +
> +Required properties:
> +- compatible: Should be "xlnx,axi-vdma-1.00.a"
> +- #dma-cells: Should be <1>, see "dmas" property below
> +- reg: Should contain VDMA registers location and length.
> +- xlnx,num-fstores: Should be the number of framebuffers as configured in h/w.
> +- dma-channel child node: Should have atleast one channel and can have upto
> + two channels per device. This node specifies the properties of each
> + DMA channel (see child node properties below).
> +
> +Optional properties:
> +- xlnx,include-sg: Tells whether configured for Scatter-mode in
> + the hardware.
> +- xlnx,flush-fsync: Tells whether which channel to Flush on Frame sync.
> + It takes following values:
> + {1}, flush both channels
> + {2}, flush mm2s channel
> + {3}, flush s2mm channel
> +
> +Required child node properties:
> +- compatible: It should be either "xlnx,axi-vdma-mm2s-channel" or
> + "xlnx,axi-vdma-s2mm-channel".
> +- interrupts: Should contain per channel VDMA interrupts.
> +- xlnx,data-width: Should contain the stream data width, take values
> + {32,64...1024}.
> +
> +Option child node properties:
> +- xlnx,include-dre: Tells whether hardware is configured for Data
> + Realignment Engine.
> +- xlnx,genlock-mode: Tells whether Genlock synchronization is
> + enabled/disabled in hardware.
> +
> +Example:
> +++++++++
> +
> +axi_vdma_0: axivdma@40030000 {
> + compatible = "xlnx,axi-vdma-1.00.a";
> + #dma_cells = <1>;
> + reg = < 0x40030000 0x10000 >;
> + xlnx,num-fstores = <0x8>;
> + xlnx,flush-fsync = <0x1>;
> + dma-channel@40030000 {
> + compatible = "xlnx,axi-vdma-mm2s-channel";
> + interrupts = < 0 54 4 >;
> + xlnx,datawidth = <0x40>;
> + } ;
> + dma-channel@40030030 {
> + compatible = "xlnx,axi-vdma-s2mm-channel";
> + interrupts = < 0 53 4 >;
> + xlnx,datawidth = <0x40>;
> + } ;
> +} ;
> +
> +
> +* DMA client
> +
> +Required properties:
> +- dmas: a list of <[Video DMA device phandle] [Channel ID]> pairs,
> + where Channel ID is '0' for write/tx and '1' for read/rx
> + channel.
> +- dma-names: a list of DMA channel names, one per "dmas" entry
> +
> +Example:
> +++++++++
> +
> +vdmatest_0: vdmatest@0 {
> + compatible ="xlnx,axi-vdma-test-1.00.a";
> + dmas = <&axi_vdma_0 0
> + &axi_vdma_0 1>;
> + dma-names = "vdma0", "vdma1";
> +} ;
> diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
> index c823daa..2a74651 100644
> --- a/drivers/dma/Kconfig
> +++ b/drivers/dma/Kconfig
> @@ -334,6 +334,20 @@ config K3_DMA
> Support the DMA engine for Hisilicon K3 platform
> devices.
>
> +config XILINX_VDMA
> + tristate "Xilinx AXI VDMA Engine"
> + depends on (ARCH_ZYNQ || MICROBLAZE)
> + select DMA_ENGINE
> + help
> + Enable support for Xilinx AXI VDMA Soft IP.
> +
> + This engine provides high-bandwidth direct memory access
> + between memory and AXI4-Stream video type target
> + peripherals including peripherals which support AXI4-
> + Stream Video Protocol. It has two stream interfaces/
> + channels, Memory Mapped to Stream (MM2S) and Stream to
> + Memory Mapped (S2MM) for the data transfers.
> +
> config DMA_ENGINE
> bool
>
> diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
> index 0ce2da9..d84130b 100644
> --- a/drivers/dma/Makefile
> +++ b/drivers/dma/Makefile
> @@ -42,3 +42,4 @@ obj-$(CONFIG_MMP_PDMA) += mmp_pdma.o
> obj-$(CONFIG_DMA_JZ4740) += dma-jz4740.o
> obj-$(CONFIG_TI_CPPI41) += cppi41.o
> obj-$(CONFIG_K3_DMA) += k3dma.o
> +obj-y += xilinx/
> diff --git a/drivers/dma/xilinx/Makefile b/drivers/dma/xilinx/Makefile
> new file mode 100644
> index 0000000..3c4e9f2
> --- /dev/null
> +++ b/drivers/dma/xilinx/Makefile
> @@ -0,0 +1 @@
> +obj-$(CONFIG_XILINX_VDMA) += xilinx_vdma.o
> diff --git a/drivers/dma/xilinx/xilinx_vdma.c b/drivers/dma/xilinx/xilinx_vdma.c
> new file mode 100644
> index 0000000..4c0d04c
> --- /dev/null
> +++ b/drivers/dma/xilinx/xilinx_vdma.c
> @@ -0,0 +1,1486 @@
> +/*
> + * DMA driver for Xilinx Video DMA Engine
> + *
> + * Copyright (C) 2010-2014 Xilinx, Inc. All rights reserved.
> + *
> + * Based on the Freescale DMA driver.
> + *
> + * Description:
> + * The AXI Video Direct Memory Access (AXI VDMA) core is a soft Xilinx IP
> + * core that provides high-bandwidth direct memory access between memory
> + * and AXI4-Stream type video target peripherals. The core provides efficient
> + * two dimensional DMA operations with independent asynchronous read (S2MM)
> + * and write (MM2S) channel operation. It can be configured to have either
> + * one channel or two channels. If configured as two channels, one is to
> + * transmit to the video device (MM2S) and another is to receive from the
> + * video device (S2MM). Initialization, status, interrupt and management
> + * registers are accessed through an AXI4-Lite slave interface.
> + *
> + * This program is free software: you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation, either version 2 of the License, or
> + * (at your option) any later version.
> + */
> +
> +#include <linux/amba/xilinx_dma.h>
> +#include <linux/bitops.h>
> +#include <linux/dmapool.h>
> +#include <linux/init.h>
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/of_address.h>
> +#include <linux/of_dma.h>
> +#include <linux/of_platform.h>
> +#include <linux/of_irq.h>
> +#include <linux/slab.h>
> +
> +/* Register/Descriptor Offsets */
> +#define XILINX_VDMA_MM2S_CTRL_OFFSET 0x0000
> +#define XILINX_VDMA_S2MM_CTRL_OFFSET 0x0030
> +#define XILINX_VDMA_MM2S_DESC_OFFSET 0x0050
> +#define XILINX_VDMA_S2MM_DESC_OFFSET 0x00a0
> +
> +/* Control Registers */
> +#define XILINX_VDMA_REG_DMACR 0x0000
> +#define XILINX_VDMA_DMACR_DELAY_MAX 0xff
> +#define XILINX_VDMA_DMACR_DELAY_SHIFT 24
> +#define XILINX_VDMA_DMACR_FRAME_COUNT_MAX 0xff
> +#define XILINX_VDMA_DMACR_FRAME_COUNT_SHIFT 16
> +#define XILINX_VDMA_DMACR_ERR_IRQ BIT(14)
> +#define XILINX_VDMA_DMACR_DLY_CNT_IRQ BIT(13)
> +#define XILINX_VDMA_DMACR_FRM_CNT_IRQ BIT(12)
> +#define XILINX_VDMA_DMACR_MASTER_SHIFT 8
> +#define XILINX_VDMA_DMACR_FSYNCSRC_SHIFT 5
> +#define XILINX_VDMA_DMACR_FRAMECNT_EN BIT(4)
> +#define XILINX_VDMA_DMACR_GENLOCK_EN BIT(3)
> +#define XILINX_VDMA_DMACR_RESET BIT(2)
> +#define XILINX_VDMA_DMACR_CIRC_EN BIT(1)
> +#define XILINX_VDMA_DMACR_RUNSTOP BIT(0)
> +#define XILINX_VDMA_DMACR_DELAY_MASK \
> + (XILINX_VDMA_DMACR_DELAY_MAX << \
> + XILINX_VDMA_DMACR_DELAY_SHIFT)
> +#define XILINX_VDMA_DMACR_FRAME_COUNT_MASK \
> + (XILINX_VDMA_DMACR_FRAME_COUNT_MAX << \
> + XILINX_VDMA_DMACR_FRAME_COUNT_SHIFT)
> +#define XILINX_VDMA_DMACR_MASTER_MASK \
> + (0xf << XILINX_VDMA_DMACR_MASTER_SHIFT)
> +#define XILINX_VDMA_DMACR_FSYNCSRC_MASK \
> + (3 << XILINX_VDMA_DMACR_FSYNCSRC_SHIFT)
> +
> +#define XILINX_VDMA_REG_DMASR 0x0004
> +#define XILINX_VDMA_DMASR_DELAY_SHIFT 24
> +#define XILINX_VDMA_DMASR_FRAME_COUNT_SHIFT 16
> +#define XILINX_VDMA_DMASR_EOL_LATE_ERR BIT(15)
> +#define XILINX_VDMA_DMASR_ERR_IRQ BIT(14)
> +#define XILINX_VDMA_DMASR_DLY_CNT_IRQ BIT(13)
> +#define XILINX_VDMA_DMASR_FRM_CNT_IRQ BIT(12)
> +#define XILINX_VDMA_DMASR_SOF_LATE_ERR BIT(11)
> +#define XILINX_VDMA_DMASR_SG_DEC_ERR BIT(10)
> +#define XILINX_VDMA_DMASR_SG_SLV_ERR BIT(9)
> +#define XILINX_VDMA_DMASR_EOF_EARLY_ERR BIT(8)
> +#define XILINX_VDMA_DMASR_SOF_EARLY_ERR BIT(7)
> +#define XILINX_VDMA_DMASR_DMA_DEC_ERR BIT(6)
> +#define XILINX_VDMA_DMASR_DMA_SLAVE_ERR BIT(5)
> +#define XILINX_VDMA_DMASR_DMA_INT_ERR BIT(4)
> +#define XILINX_VDMA_DMASR_IDLE BIT(1)
> +#define XILINX_VDMA_DMASR_HALTED BIT(0)
> +
> +#define XILINX_VDMA_DMASR_DELAY_MASK \
> + (0xff << XILINX_VDMA_DMASR_DELAY_SHIFT)
> +#define XILINX_VDMA_DMASR_FRAME_COUNT_MASK \
> + (0xff << XILINX_VDMA_DMASR_FRAME_COUNT_SHIFT)
Does 0xff require to be a separate definition in both above cases?
> +
> +#define XILINX_VDMA_REG_CURDESC 0x0008
> +#define XILINX_VDMA_REG_TAILDESC 0x0010
> +#define XILINX_VDMA_REG_REG_INDEX 0x0014
> +#define XILINX_VDMA_REG_FRMSTORE 0x0018
> +#define XILINX_VDMA_REG_THRESHOLD 0x001c
> +#define XILINX_VDMA_REG_FRMPTR_STS 0x0024
> +#define XILINX_VDMA_REG_PARK_PTR 0x0028
> +#define XILINX_VDMA_PARK_PTR_WR_REF_SHIFT 8
> +#define XILINX_VDMA_PARK_PTR_RD_REF_SHIFT 0
> +#define XILINX_VDMA_REG_VDMA_VERSION 0x002c
> +
> +/* Register Direct Mode Registers */
> +#define XILINX_VDMA_REG_VSIZE 0x0000
> +#define XILINX_VDMA_REG_HSIZE 0x0004
> +
> +#define XILINX_VDMA_REG_FRMDLY_STRIDE 0x0008
> +#define XILINX_VDMA_FRMDLY_STRIDE_FRMDLY_SHIFT 24
> +#define XILINX_VDMA_FRMDLY_STRIDE_STRIDE_SHIFT 0
> +#define XILINX_VDMA_FRMDLY_STRIDE_FRMDLY_MASK \
> + (0x1f << \
> + XILINX_VDMA_FRMDLY_STRIDE_FRMDLY_SHIFT)
> +#define XILINX_VDMA_FRMDLY_STRIDE_STRIDE_MASK \
> + (0xffff << \
> + XILINX_VDMA_FRMDLY_STRIDE_STRIDE_MASK)
> +
> +#define XILINX_VDMA_REG_START_ADDRESS(n) (0x000c + 4 * (n))
> +
> +/* Hw specific definitions */
HW or Hardware
> +#define XILINX_VDMA_MAX_CHANS_PER_DEVICE 0x2
> +
> +#define XILINX_VDMA_DMAXR_ALL_IRQ_MASK (XILINX_VDMA_DMASR_FRM_CNT_IRQ | \
> + XILINX_VDMA_DMASR_DLY_CNT_IRQ | \
> + XILINX_VDMA_DMASR_ERR_IRQ)
> +
> +#define XILINX_VDMA_DMASR_ALL_ERR_MASK (XILINX_VDMA_DMASR_EOL_LATE_ERR | \
> + XILINX_VDMA_DMASR_SOF_LATE_ERR | \
> + XILINX_VDMA_DMASR_SG_DEC_ERR | \
> + XILINX_VDMA_DMASR_SG_SLV_ERR | \
> + XILINX_VDMA_DMASR_EOF_EARLY_ERR | \
> + XILINX_VDMA_DMASR_SOF_EARLY_ERR | \
> + XILINX_VDMA_DMASR_DMA_DEC_ERR | \
> + XILINX_VDMA_DMASR_DMA_SLAVE_ERR | \
> + XILINX_VDMA_DMASR_DMA_INT_ERR)
> +
> +/*
> + * Recoverable errors are DMA Internal error, SOF Early, EOF Early and SOF Late.
> + * They are only recoverable when C_FLUSH_ON_FSYNC is enabled in the h/w system.
> + */
> +#define XILINX_VDMA_DMASR_ERR_RECOVER_MASK \
> + (XILINX_VDMA_DMASR_SOF_LATE_ERR | \
Do you need so many tabs for an indentation here and in other places?
May be better to keep some style here (I mean on which line you start
the value of the definition).
> + XILINX_VDMA_DMASR_EOF_EARLY_ERR | \
> + XILINX_VDMA_DMASR_SOF_EARLY_ERR | \
> + XILINX_VDMA_DMASR_DMA_INT_ERR)
> +
> +/* Axi VDMA Flush on Fsync bits */
> +#define XILINX_VDMA_FLUSH_S2MM 3
> +#define XILINX_VDMA_FLUSH_MM2S 2
> +#define XILINX_VDMA_FLUSH_BOTH 1
> +
> +/* Delay loop counter to prevent hardware failure */
> +#define XILINX_VDMA_LOOP_COUNT 1000000
> +
> +/**
> + * struct xilinx_vdma_desc_hw - Hardware Descriptor
> + * @next_desc: Next Descriptor Pointer @0x00
> + * @pad1: Reserved @0x04
> + * @buf_addr: Buffer address @0x08
> + * @pad2: Reserved @0x0C
> + * @vsize: Vertical Size @0x10
> + * @hsize: Horizontal Size @0x14
> + * @stride: Number of bytes between the first
> + * pixels of each horizontal line @0x18
> + */
> +struct xilinx_vdma_desc_hw {
> + u32 next_desc;
> + u32 pad1;
> + u32 buf_addr;
> + u32 pad2;
> + u32 vsize;
> + u32 hsize;
> + u32 stride;
> +} __aligned(64);
> +
> +/**
> + * struct xilinx_vdma_tx_segment - Descriptor segment
> + * @hw: Hardware descriptor
> + * @node: Node in the descriptor segments list
> + * @cookie: Segment cookie
> + * @phys: Physical address of segment
> + */
> +struct xilinx_vdma_tx_segment {
> + struct xilinx_vdma_desc_hw hw;
> + struct list_head node;
> + dma_cookie_t cookie;
> + dma_addr_t phys;
> +} __aligned(64);
> +
> +/**
> + * struct xilinx_vdma_tx_descriptor - Per Transaction structure
> + * @async_tx: Async transaction descriptor
> + * @segments: TX segments list
> + * @node: Node in the channel descriptors list
> + */
> +struct xilinx_vdma_tx_descriptor {
> + struct dma_async_tx_descriptor async_tx;
> + struct list_head segments;
> + struct list_head node;
> +};
> +
> +#define to_vdma_tx_descriptor(tx) \
> + container_of(tx, struct xilinx_vdma_tx_descriptor, async_tx)
> +
> +/**
> + * struct xilinx_vdma_chan - Driver specific VDMA channel structure
> + * @xdev: Driver specific device structure
> + * @ctrl_offset: Control registers offset
> + * @desc_offset: TX descriptor registers offset
> + * @completed_cookie: Maximum cookie completed
> + * @cookie: The current cookie
> + * @lock: Descriptor operation lock
> + * @pending_list: Descriptors waiting
> + * @active_desc: Active descriptor
> + * @done_list: Complete descriptors
> + * @common: DMA common channel
> + * @desc_pool: Descriptors pool
> + * @dev: The dma device
> + * @irq: Channel IRQ
> + * @id: Channel ID
> + * @direction: Transfer direction
> + * @num_frms: Number of frames
> + * @has_sg: Support scatter transfers
> + * @genlock: Support genlock mode
> + * @err: Channel has errors
> + * @tasklet: Cleanup work after irq
> + * @config: Device configuration info
> + * @flush_on_fsync: Flush on Frame sync
> + */
> +struct xilinx_vdma_chan {
> + struct xilinx_vdma_device *xdev;
> + u32 ctrl_offset;
> + u32 desc_offset;
> + dma_cookie_t completed_cookie;
> + dma_cookie_t cookie;
> + spinlock_t lock;
> + struct list_head pending_list;
> + struct xilinx_vdma_tx_descriptor *active_desc;
> + struct list_head done_list;
> + struct dma_chan common;
> + struct dma_pool *desc_pool;
> + struct device *dev;
> + int irq;
> + int id;
> + enum dma_transfer_direction direction;
> + int num_frms;
> + bool has_sg;
> + bool genlock;
> + bool err;
> + struct tasklet_struct tasklet;
> + struct xilinx_vdma_config config;
> + bool flush_on_fsync;
> +};
> +
> +/**
> + * struct xilinx_vdma_device - VDMA device structure
> + * @regs: I/O mapped base address
> + * @dev: Device Structure
> + * @common: DMA device structure
> + * @chan: Driver specific VDMA channel
> + * @has_sg: Specifies whether Scatter-Gather is present or not
> + * @flush_on_fsync: Flush on frame sync
> + */
> +struct xilinx_vdma_device {
> + void __iomem *regs;
> + struct device *dev;
> + struct dma_device common;
> + struct xilinx_vdma_chan *chan[XILINX_VDMA_MAX_CHANS_PER_DEVICE];
> + bool has_sg;
> + u32 flush_on_fsync;
> +};
> +
> +#define to_xilinx_chan(chan) \
> + container_of(chan, struct xilinx_vdma_chan, common)
> +
> +/* IO accessors */
> +static inline u32 vdma_read(struct xilinx_vdma_chan *chan, u32 reg)
> +{
> + return ioread32(chan->xdev->regs + reg);
> +}
> +
> +static inline void vdma_write(struct xilinx_vdma_chan *chan, u32 reg, u32 value)
> +{
> + iowrite32(value, chan->xdev->regs + reg);
> +}
> +
> +static inline void vdma_desc_write(struct xilinx_vdma_chan *chan, u32 reg,
> + u32 value)
> +{
> + vdma_write(chan, chan->desc_offset + reg, value);
> +}
> +
> +static inline u32 vdma_ctrl_read(struct xilinx_vdma_chan *chan, u32 reg)
> +{
> + return vdma_read(chan, chan->ctrl_offset + reg);
> +}
> +
> +static inline void vdma_ctrl_write(struct xilinx_vdma_chan *chan, u32 reg,
> + u32 value)
> +{
> + vdma_write(chan, chan->ctrl_offset + reg, value);
> +}
> +
> +static inline void vdma_ctrl_clr(struct xilinx_vdma_chan *chan, u32 reg,
> + u32 clr)
> +{
> + vdma_ctrl_write(chan, reg, vdma_ctrl_read(chan, reg) & ~clr);
> +}
> +
> +static inline void vdma_ctrl_set(struct xilinx_vdma_chan *chan, u32 reg,
> + u32 set)
> +{
> + vdma_ctrl_write(chan, reg, vdma_ctrl_read(chan, reg) | set);
> +}
> +
> +/* -----------------------------------------------------------------------------
> + * Descriptors and segments alloc and free
> + */
> +
> +/**
> + * xilinx_vdma_alloc_tx_segment - Allocate transaction segment
> + * @chan: Driver specific VDMA channel
> + *
> + * Return: The allocated segment on success and NULL on failure.
> + */
> +static struct xilinx_vdma_tx_segment *
> +xilinx_vdma_alloc_tx_segment(struct xilinx_vdma_chan *chan)
> +{
> + struct xilinx_vdma_tx_segment *segment;
> + dma_addr_t phys;
> +
> + segment = dma_pool_alloc(chan->desc_pool, GFP_ATOMIC, &phys);
> + if (!segment)
> + return NULL;
> +
> + memset(segment, 0, sizeof(*segment));
> + segment->phys = phys;
> +
> + return segment;
> +}
> +
> +/**
> + * xilinx_vdma_free_tx_segment - Free transaction segment
> + * @chan: Driver specific VDMA channel
> + * @segment: VDMA transaction segment
> + */
> +static void xilinx_vdma_free_tx_segment(struct xilinx_vdma_chan *chan,
> + struct xilinx_vdma_tx_segment *segment)
> +{
> + dma_pool_free(chan->desc_pool, segment, segment->phys);
> +}
> +
> +/**
> + * xilinx_vdma_tx_descriptor - Allocate transaction descriptor
> + * @chan: Driver specific VDMA channel
> + *
> + * Return: The allocated descriptor on success and NULL on failure.
> + */
> +static struct xilinx_vdma_tx_descriptor *
> +xilinx_vdma_alloc_tx_descriptor(struct xilinx_vdma_chan *chan)
> +{
> + struct xilinx_vdma_tx_descriptor *desc;
> +
> + desc = kzalloc(sizeof(*desc), GFP_KERNEL);
> + if (!desc)
> + return NULL;
> +
> + INIT_LIST_HEAD(&desc->segments);
> +
> + return desc;
> +}
> +
> +/**
> + * xilinx_vdma_free_tx_descriptor - Free transaction descriptor
> + * @chan: Driver specific VDMA channel
> + * @desc: VDMA transaction descriptor
> + */
> +static void
> +xilinx_vdma_free_tx_descriptor(struct xilinx_vdma_chan *chan,
> + struct xilinx_vdma_tx_descriptor *desc)
> +{
> + struct xilinx_vdma_tx_segment *segment, *next;
> +
> + if (!desc)
> + return;
> +
> + list_for_each_entry_safe(segment, next, &desc->segments, node) {
> + list_del(&segment->node);
> + xilinx_vdma_free_tx_segment(chan, segment);
> + }
> +
> + kfree(desc);
> +}
> +
> +/* Required functions */
> +
> +/**
> + * xilinx_vdma_free_descriptors - Free descriptors list
> + * @chan: Driver specific VDMA channel
> + * @list: List to parse and delete the descriptor
> + */
> +static void xilinx_vdma_free_desc_list(struct xilinx_vdma_chan *chan,
> + struct list_head *list)
> +{
> + struct xilinx_vdma_tx_descriptor *desc, *next;
> +
> + list_for_each_entry_safe(desc, next, list, node) {
> + list_del(&desc->node);
> + xilinx_vdma_free_tx_descriptor(chan, desc);
> + }
> +}
> +
> +/**
> + * xilinx_vdma_free_descriptors - Free channel descriptors
> + * @chan: Driver specific VDMA channel
> + */
> +static void xilinx_vdma_free_descriptors(struct xilinx_vdma_chan *chan)
> +{
> + unsigned long flags;
> +
> + spin_lock_irqsave(&chan->lock, flags);
> +
> + xilinx_vdma_free_desc_list(chan, &chan->pending_list);
> + xilinx_vdma_free_desc_list(chan, &chan->done_list);
> +
> + xilinx_vdma_free_tx_descriptor(chan, chan->active_desc);
> + chan->active_desc = NULL;
> +
> + spin_unlock_irqrestore(&chan->lock, flags);
> +}
> +
> +/**
> + * xilinx_vdma_free_chan_resources - Free channel resources
> + * @dchan: DMA channel
> + */
> +static void xilinx_vdma_free_chan_resources(struct dma_chan *dchan)
> +{
> + struct xilinx_vdma_chan *chan = to_xilinx_chan(dchan);
> +
> + dev_dbg(chan->dev, "Free all channel resources.\n");
> +
> + tasklet_kill(&chan->tasklet);
> + xilinx_vdma_free_descriptors(chan);
> + dma_pool_destroy(chan->desc_pool);
> + chan->desc_pool = NULL;
> +}
> +
> +/**
> + * xilinx_vdma_chan_desc_cleanup - Clean channel descriptors
> + * @chan: Driver specific VDMA channel
> + */
> +static void xilinx_vdma_chan_desc_cleanup(struct xilinx_vdma_chan *chan)
> +{
> + struct xilinx_vdma_tx_descriptor *desc, *next;
> + unsigned long flags;
> +
> + spin_lock_irqsave(&chan->lock, flags);
> +
> + list_for_each_entry_safe(desc, next, &chan->done_list, node) {
> + dma_async_tx_callback callback;
> + void *callback_param;
> +
> + /* Remove from the list of running transactions */
> + list_del(&desc->node);
> +
> + /* Run the link descriptor callback function */
> + callback = desc->async_tx.callback;
> + callback_param = desc->async_tx.callback_param;
> + if (callback) {
> + spin_unlock_irqrestore(&chan->lock, flags);
> + callback(callback_param);
> + spin_lock_irqsave(&chan->lock, flags);
> + }
> +
> + /* Run any dependencies, then free the descriptor */
> + dma_run_dependencies(&desc->async_tx);
> + xilinx_vdma_free_tx_descriptor(chan, desc);
> + }
> +
> + spin_unlock_irqrestore(&chan->lock, flags);
> +}
> +
> +/**
> + * xilinx_vdma_do_tasklet - Schedule completion tasklet
> + * @data: Pointer to the Xilinx VDMA channel structure
> + */
> +static void xilinx_vdma_do_tasklet(unsigned long data)
> +{
> + struct xilinx_vdma_chan *chan = (struct xilinx_vdma_chan *)data;
> +
> + xilinx_vdma_chan_desc_cleanup(chan);
> +}
> +
> +/**
> + * xilinx_vdma_alloc_chan_resources - Allocate channel resources
> + * @dchan: DMA channel
> + *
> + * Return: '1' on success and failure value on error
May be return 0 on success as it usual practice? Here and in the other
places as well.
> + */
> +static int xilinx_vdma_alloc_chan_resources(struct dma_chan *dchan)
> +{
> + struct xilinx_vdma_chan *chan = to_xilinx_chan(dchan);
> +
> + /* Has this channel already been allocated? */
> + if (chan->desc_pool)
> + return 1;
> +
> + /*
> + * We need the descriptor to be aligned to 64bytes
> + * for meeting Xilinx VDMA specification requirement.
> + */
> + chan->desc_pool = dma_pool_create("xilinx_vdma_desc_pool",
> + chan->dev,
> + sizeof(struct xilinx_vdma_tx_segment),
> + __alignof__(struct xilinx_vdma_tx_segment), 0);
> + if (!chan->desc_pool) {
> + dev_err(chan->dev,
> + "unable to allocate channel %d descriptor pool\n",
> + chan->id);
> + return -ENOMEM;
> + }
> +
> + tasklet_init(&chan->tasklet, xilinx_vdma_do_tasklet,
> + (unsigned long)chan);
> +
> + chan->completed_cookie = DMA_MIN_COOKIE;
> + chan->cookie = DMA_MIN_COOKIE;
> +
> + /* There is at least one descriptor free to be allocated */
> + return 1;
> +}
> +
> +/**
> + * xilinx_vdma_tx_status - Get VDMA transaction status
> + * @dchan: DMA channel
> + * @cookie: Transaction identifier
> + * @txstate: Transaction state
> + *
> + * Return: DMA transaction status
> + */
> +static enum dma_status xilinx_vdma_tx_status(struct dma_chan *dchan,
> + dma_cookie_t cookie,
> + struct dma_tx_state *txstate)
> +{
> + struct xilinx_vdma_chan *chan = to_xilinx_chan(dchan);
> + dma_cookie_t last_used;
> + dma_cookie_t last_complete;
> +
> + xilinx_vdma_chan_desc_cleanup(chan);
> +
> + last_used = dchan->cookie;
> + last_complete = chan->completed_cookie;
> +
> + dma_set_tx_state(txstate, last_complete, last_used, 0);
> +
> + return dma_async_is_complete(cookie, last_complete, last_used);
> +}
> +
> +/**
> + * xilinx_vdma_is_running - Check if VDMA channel is running
> + * @chan: Driver specific VDMA channel
> + *
> + * Return: '1' if running, '0' if not.
> + */
> +static int xilinx_vdma_is_running(struct xilinx_vdma_chan *chan)
> +{
> + return !(vdma_ctrl_read(chan, XILINX_VDMA_REG_DMASR) &
> + XILINX_VDMA_DMASR_HALTED) &&
> + (vdma_ctrl_read(chan, XILINX_VDMA_REG_DMACR) &
> + XILINX_VDMA_DMACR_RUNSTOP);
> +}
> +
> +/**
> + * xilinx_vdma_is_idle - Check if VDMA channel is idle
> + * @chan: Driver specific VDMA channel
> + *
> + * Return: '1' if idle, '0' if not.
> + */
> +static int xilinx_vdma_is_idle(struct xilinx_vdma_chan *chan)
> +{
> + return vdma_ctrl_read(chan, XILINX_VDMA_REG_DMASR) &
> + XILINX_VDMA_DMASR_IDLE;
> +}
> +
> +/**
> + * xilinx_vdma_halt - Halt VDMA channel
> + * @chan: Driver specific VDMA channel
> + */
> +static void xilinx_vdma_halt(struct xilinx_vdma_chan *chan)
> +{
> + int loop = XILINX_VDMA_LOOP_COUNT + 1;
> +
> + vdma_ctrl_clr(chan, XILINX_VDMA_REG_DMACR, XILINX_VDMA_DMACR_RUNSTOP);
> +
> + /* Wait for the hardware to halt */
> + while (loop--)
> + if (vdma_ctrl_read(chan, XILINX_VDMA_REG_DMASR) &
> + XILINX_VDMA_DMASR_HALTED)
> + break;
> +
> + if (!loop) {
> + dev_err(chan->dev, "Cannot stop channel %p: %x\n",
> + chan, vdma_ctrl_read(chan, XILINX_VDMA_REG_DMASR));
> + chan->err = true;
> + }
> +
> + return;
> +}
> +
> +/**
> + * xilinx_vdma_start - Start VDMA channel
> + * @chan: Driver specific VDMA channel
> + */
> +static void xilinx_vdma_start(struct xilinx_vdma_chan *chan)
> +{
> + int loop = XILINX_VDMA_LOOP_COUNT + 1;
> +
> + vdma_ctrl_set(chan, XILINX_VDMA_REG_DMACR, XILINX_VDMA_DMACR_RUNSTOP);
> +
> + /* Wait for the hardware to start */
> + while (loop--)
> + if (!(vdma_ctrl_read(chan, XILINX_VDMA_REG_DMASR) &
> + XILINX_VDMA_DMASR_HALTED))
> + break;
> +
> + if (!loop) {
> + dev_err(chan->dev, "Cannot start channel %p: %x\n",
> + chan, vdma_ctrl_read(chan, XILINX_VDMA_REG_DMASR));
> +
> + chan->err = true;
> + }
> +
> + return;
> +}
> +
> +/**
> + * xilinx_vdma_start_transfer - Starts VDMA transfer
> + * @chan: Driver specific channel struct pointer
> + */
> +static void xilinx_vdma_start_transfer(struct xilinx_vdma_chan *chan)
> +{
> + struct xilinx_vdma_config *config = &chan->config;
> + struct xilinx_vdma_tx_descriptor *desc;
> + unsigned long flags;
> + u32 reg;
> + struct xilinx_vdma_tx_segment *head, *tail = NULL;
> +
> + if (chan->err)
> + return;
> +
> + spin_lock_irqsave(&chan->lock, flags);
> +
> + /* There's already an active descriptor, bail out. */
> + if (chan->active_desc)
> + goto out_unlock;
> +
> + if (list_empty(&chan->pending_list))
> + goto out_unlock;
> +
> + desc = list_first_entry(&chan->pending_list,
> + struct xilinx_vdma_tx_descriptor, node);
> +
> + /* If it is SG mode and hardware is busy, cannot submit */
> + if (chan->has_sg && xilinx_vdma_is_running(chan) &&
> + !xilinx_vdma_is_idle(chan)) {
> + dev_dbg(chan->dev, "DMA controller still busy\n");
> + goto out_unlock;
> + }
> +
> + if (chan->err)
> + goto out_unlock;
> +
> + /*
> + * If hardware is idle, then all descriptors on the running lists are
> + * done, start new transfers
> + */
> + if (chan->has_sg) {
> + head = list_first_entry(&desc->segments,
> + struct xilinx_vdma_tx_segment, node);
> + tail = list_entry(desc->segments.prev,
> + struct xilinx_vdma_tx_segment, node);
> +
> + vdma_ctrl_write(chan, XILINX_VDMA_REG_CURDESC, head->phys);
> + }
> +
> + /* Configure the hardware using info in the config structure */
> + reg = vdma_ctrl_read(chan, XILINX_VDMA_REG_DMACR);
> +
> + if (config->frm_cnt_en)
> + reg |= XILINX_VDMA_DMACR_FRAMECNT_EN;
> + else
> + reg &= ~XILINX_VDMA_DMACR_FRAMECNT_EN;
> +
> + /*
> + * With SG, start with circular mode, so that BDs can be fetched.
> + * In direct register mode, if not parking, enable circular mode
> + */
> + if (chan->has_sg || !config->park)
> + reg |= XILINX_VDMA_DMACR_CIRC_EN;
> +
> + if (config->park)
> + reg &= ~XILINX_VDMA_DMACR_CIRC_EN;
> +
> + vdma_ctrl_write(chan, XILINX_VDMA_REG_DMACR, reg);
> +
> + if (config->park && (config->park_frm >= 0) &&
> + (config->park_frm < chan->num_frms)) {
> + if (chan->direction == DMA_MEM_TO_DEV)
> + vdma_write(chan, XILINX_VDMA_REG_PARK_PTR,
> + config->park_frm <<
> + XILINX_VDMA_PARK_PTR_RD_REF_SHIFT);
> + else
> + vdma_write(chan, XILINX_VDMA_REG_PARK_PTR,
> + config->park_frm <<
> + XILINX_VDMA_PARK_PTR_WR_REF_SHIFT);
> + }
> +
> + /* Start the hardware */
> + xilinx_vdma_start(chan);
> +
> + if (chan->err)
> + goto out_unlock;
> +
> + /* Start the transfer */
> + if (chan->has_sg) {
> + vdma_ctrl_write(chan, XILINX_VDMA_REG_TAILDESC, tail->phys);
> + } else {
> + struct xilinx_vdma_tx_segment *segment;
> + int i = 0;
> +
> + list_for_each_entry(segment, &desc->segments, node)
> + vdma_desc_write(chan,
> + XILINX_VDMA_REG_START_ADDRESS(i++),
> + segment->hw.buf_addr);
> +
> + vdma_desc_write(chan, XILINX_VDMA_REG_HSIZE, config->hsize);
> + vdma_desc_write(chan, XILINX_VDMA_REG_FRMDLY_STRIDE,
> + (config->frm_dly <<
> + XILINX_VDMA_FRMDLY_STRIDE_FRMDLY_SHIFT) |
> + (config->stride <<
> + XILINX_VDMA_FRMDLY_STRIDE_STRIDE_SHIFT));
> + vdma_desc_write(chan, XILINX_VDMA_REG_VSIZE, config->vsize);
> + }
> +
> + list_del(&desc->node);
> + chan->active_desc = desc;
> +
> +out_unlock:
> + spin_unlock_irqrestore(&chan->lock, flags);
> +}
> +
> +/**
> + * xilinx_vdma_issue_pending - Issue pending transactions
> + * @dchan: DMA channel
> + */
> +static void xilinx_vdma_issue_pending(struct dma_chan *dchan)
> +{
> + struct xilinx_vdma_chan *chan = to_xilinx_chan(dchan);
> +
> + xilinx_vdma_start_transfer(chan);
> +}
> +
> +/**
> + * xilinx_vdma_complete_descriptor - Mark the active descriptor as complete
> + * @chan : xilinx DMA channel
> + *
> + * CONTEXT: hardirq
> + */
> +static void xilinx_vdma_complete_descriptor(struct xilinx_vdma_chan *chan)
> +{
> + struct xilinx_vdma_tx_descriptor *desc;
> + unsigned long flags;
> +
> + spin_lock_irqsave(&chan->lock, flags);
> +
> + desc = chan->active_desc;
> + if (!desc) {
> + dev_dbg(chan->dev, "no running descriptors\n");
> + goto out_unlock;
> + }
> +
> + list_add_tail(&desc->node, &chan->done_list);
> +
> + /* Update the completed cookie and reset the active descriptor. */
> + chan->completed_cookie = desc->async_tx.cookie;
> + chan->active_desc = NULL;
> +
> +out_unlock:
> + spin_unlock_irqrestore(&chan->lock, flags);
> +}
> +
> +/**
> + * xilinx_vdma_reset - Reset VDMA channel
> + * @chan: Driver specific VDMA channel
> + *
> + * Return: '0' on success and failure value on error
> + */
> +static int xilinx_vdma_reset(struct xilinx_vdma_chan *chan)
> +{
> + int loop = XILINX_VDMA_LOOP_COUNT + 1;
> + u32 tmp;
> +
> + vdma_ctrl_set(chan, XILINX_VDMA_REG_DMACR, XILINX_VDMA_DMACR_RESET);
> +
> + tmp = vdma_ctrl_read(chan, XILINX_VDMA_REG_DMACR) &
> + XILINX_VDMA_DMACR_RESET;
> +
> + /* Wait for the hardware to finish reset */
> + while (loop-- && tmp)
> + tmp = vdma_ctrl_read(chan, XILINX_VDMA_REG_DMACR) &
> + XILINX_VDMA_DMACR_RESET;
> +
> + if (!loop) {
> + dev_err(chan->dev, "reset timeout, cr %x, sr %x\n",
> + vdma_ctrl_read(chan, XILINX_VDMA_REG_DMACR),
> + vdma_ctrl_read(chan, XILINX_VDMA_REG_DMASR));
> + return -ETIMEDOUT;
> + }
> +
> + chan->err = false;
> +
> + return 0;
> +}
> +
> +/**
> + * xilinx_vdma_chan_reset - Reset VDMA channel and enable interrupts
> + * @chan: Driver specific VDMA channel
> + *
> + * Return: '0' on success and failure value on error
> + */
> +static int xilinx_vdma_chan_reset(struct xilinx_vdma_chan *chan)
> +{
> + int err;
> +
> + /* Reset VDMA */
> + err = xilinx_vdma_reset(chan);
> + if (err)
> + return err;
> +
> + /* Enable interrupts */
> + vdma_ctrl_set(chan, XILINX_VDMA_REG_DMACR,
> + XILINX_VDMA_DMAXR_ALL_IRQ_MASK);
> +
> + return 0;
> +}
> +
> +/**
> + * xilinx_vdma_irq_handler - VDMA Interrupt handler
> + * @irq: IRQ number
> + * @data: Pointer to the Xilinx VDMA channel structure
> + *
> + * Return: IRQ_HANDLED/IRQ_NONE
> + */
> +static irqreturn_t xilinx_vdma_irq_handler(int irq, void *data)
> +{
> + struct xilinx_vdma_chan *chan = data;
> + u32 status;
> +
> + /* Read the status and ack the interrupts. */
> + status = vdma_ctrl_read(chan, XILINX_VDMA_REG_DMASR);
> + if (!(status & XILINX_VDMA_DMAXR_ALL_IRQ_MASK))
> + return IRQ_NONE;
> +
> + vdma_ctrl_write(chan, XILINX_VDMA_REG_DMASR,
> + status & XILINX_VDMA_DMAXR_ALL_IRQ_MASK);
> +
> + if (status & XILINX_VDMA_DMASR_ERR_IRQ) {
> + /*
> + * An error occurred. If C_FLUSH_ON_FSYNC is enabled and the
> + * error is recoverable, ignore it. Otherwise flag the error.
> + *
> + * Only recoverable errors can be cleared in the DMASR register,
> + * make sure not to write to other error bits to 1.
> + */
> + u32 errors = status & XILINX_VDMA_DMASR_ALL_ERR_MASK;
> + vdma_ctrl_write(chan, XILINX_VDMA_REG_DMASR,
> + errors & XILINX_VDMA_DMASR_ERR_RECOVER_MASK);
> +
> + if (!chan->flush_on_fsync ||
> + (errors & ~XILINX_VDMA_DMASR_ERR_RECOVER_MASK)) {
> + dev_err(chan->dev,
> + "Channel %p has errors %x, cdr %x tdr %x\n",
> + chan, errors,
> + vdma_ctrl_read(chan, XILINX_VDMA_REG_CURDESC),
> + vdma_ctrl_read(chan, XILINX_VDMA_REG_TAILDESC));
> + chan->err = true;
> + }
> + }
> +
> + if (status & XILINX_VDMA_DMASR_DLY_CNT_IRQ) {
> + /*
> + * Device takes too long to do the transfer when user requires
> + * responsiveness.
> + */
> + dev_dbg(chan->dev, "Inter-packet latency too long\n");
> + }
> +
> + if (status & XILINX_VDMA_DMASR_FRM_CNT_IRQ) {
> + xilinx_vdma_complete_descriptor(chan);
> + xilinx_vdma_start_transfer(chan);
> + }
> +
> + tasklet_schedule(&chan->tasklet);
> + return IRQ_HANDLED;
> +}
> +
> +/**
> + * xilinx_vdma_tx_submit - Submit DMA transaction
> + * @tx: Async transaction descriptor
> + *
> + * Return: cookie value on success and failure value on error
> + */
> +static dma_cookie_t xilinx_vdma_tx_submit(struct dma_async_tx_descriptor *tx)
> +{
> + struct xilinx_vdma_tx_descriptor *desc = to_vdma_tx_descriptor(tx);
> + struct xilinx_vdma_chan *chan = to_xilinx_chan(tx->chan);
> + struct xilinx_vdma_tx_segment *segment;
> + dma_cookie_t cookie;
> + unsigned long flags;
> + int err;
> +
> + if (chan->err) {
> + /*
> + * If reset fails, need to hard reset the system.
> + * Channel is no longer functional
> + */
> + err = xilinx_vdma_chan_reset(chan);
> + if (err < 0)
> + return err;
> + }
> +
> + spin_lock_irqsave(&chan->lock, flags);
> +
> + /* Assign cookies to all of the segments that make up this transaction.
> + * Use the cookie of the last segment as the transaction cookie.
> + */
Keep style of multiline comment the same over the code.
> + cookie = chan->cookie;
> +
> + list_for_each_entry(segment, &desc->segments, node) {
> + if (cookie < DMA_MAX_COOKIE)
> + cookie++;
> + else
> + cookie = DMA_MIN_COOKIE;
> +
> + segment->cookie = cookie;
> + }
> +
> + tx->cookie = cookie;
> + chan->cookie = cookie;
> +
> + /* Append the transaction to the pending transactions queue. */
> + list_add_tail(&desc->node, &chan->pending_list);
> +
> + spin_unlock_irqrestore(&chan->lock, flags);
> +
> + return cookie;
> +}
> +
> +/**
> + * xilinx_vdma_prep_slave_sg - prepare a descriptor for a DMA_SLAVE transaction
> + * @dchan: DMA channel
> + * @sgl: scatterlist to transfer to/from
> + * @sg_len: number of entries in @sgl
> + * @dir: DMA direction
> + * @flags: transfer ack flags
> + * @context: unused
> + *
> + * Return: Async transaction descriptor on success and NULL on failure
> + */
> +static struct dma_async_tx_descriptor *
> +xilinx_vdma_prep_slave_sg(struct dma_chan *dchan, struct scatterlist *sgl,
> + unsigned int sg_len, enum dma_transfer_direction dir,
> + unsigned long flags, void *context)
> +{
> + struct xilinx_vdma_chan *chan = to_xilinx_chan(dchan);
> + struct xilinx_vdma_tx_descriptor *desc;
> + struct xilinx_vdma_tx_segment *segment;
> + struct xilinx_vdma_tx_segment *prev = NULL;
> + struct scatterlist *sg;
> + int i;
> +
> + if (chan->direction != dir || sg_len == 0)
> + return NULL;
> +
> + /* Enforce one sg entry for one frame. */
> + if (sg_len != chan->num_frms) {
> + dev_err(chan->dev,
> + "number of entries %d not the same as num stores %d\n",
> + sg_len, chan->num_frms);
> + return NULL;
> + }
> +
> + /* Allocate a transaction descriptor. */
> + desc = xilinx_vdma_alloc_tx_descriptor(chan);
> + if (!desc)
> + return NULL;
> +
> + dma_async_tx_descriptor_init(&desc->async_tx, &chan->common);
> + desc->async_tx.tx_submit = xilinx_vdma_tx_submit;
> + desc->async_tx.cookie = 0;
> + async_tx_ack(&desc->async_tx);
> +
> + /* Build the list of transaction segments. */
> + for_each_sg(sgl, sg, sg_len, i) {
> + struct xilinx_vdma_desc_hw *hw;
> +
> + /* Allocate the link descriptor from DMA pool */
> + segment = xilinx_vdma_alloc_tx_segment(chan);
> + if (!segment)
> + goto error;
> +
> + /* Fill in the hardware descriptor */
> + hw = &segment->hw;
> + hw->buf_addr = sg_dma_address(sg);
> + hw->vsize = chan->config.vsize;
> + hw->hsize = chan->config.hsize;
> + hw->stride = (chan->config.frm_dly <<
> + XILINX_VDMA_FRMDLY_STRIDE_FRMDLY_SHIFT) |
> + (chan->config.stride <<
> + XILINX_VDMA_FRMDLY_STRIDE_STRIDE_SHIFT);
> + if (prev)
> + prev->hw.next_desc = segment->phys;
> +
> + /* Insert the segment into the descriptor segments list. */
> + list_add_tail(&segment->node, &desc->segments);
> +
> + prev = segment;
> + }
> +
> + /* Link the last hardware descriptor with the first. */
> + segment = list_first_entry(&desc->segments,
> + struct xilinx_vdma_tx_segment, node);
> + prev->hw.next_desc = segment->phys;
> +
> + return &desc->async_tx;
> +
> +error:
> + xilinx_vdma_free_tx_descriptor(chan, desc);
> + return NULL;
> +}
> +
> +/**
> + * xilinx_vdma_terminate_all - Halt the channel and free descriptors
> + * @chan: Driver specific VDMA Channel pointer
> + */
> +static void xilinx_vdma_terminate_all(struct xilinx_vdma_chan *chan)
> +{
> + /* Halt the DMA engine */
> + xilinx_vdma_halt(chan);
> +
> + /* Remove and free all of the descriptors in the lists */
> + xilinx_vdma_free_descriptors(chan);
> +}
> +
> +/**
> + * xilinx_vdma_slave_config - Configure VDMA channel
> + * Run-time configuration for Axi VDMA, supports:
> + * . halt the channel
> + * . configure interrupt coalescing and inter-packet delay threshold
> + * . start/stop parking
> + * . enable genlock
> + * . set transfer information using config struct
> + *
> + * @chan: Driver specific VDMA Channel pointer
> + * @cfg: Channel configuration pointer
> + *
> + * Return: '0' on success and failure value on error
> + */
> +static int xilinx_vdma_slave_config(struct xilinx_vdma_chan *chan,
> + struct xilinx_vdma_config *cfg)
> +{
> + u32 dmacr;
> +
> + if (cfg->reset)
> + return xilinx_vdma_chan_reset(chan);
> +
> + dmacr = vdma_ctrl_read(chan, XILINX_VDMA_REG_DMACR);
> +
> + /* If vsize is -1, it is park-related operations */
> + if (cfg->vsize == -1) {
> + if (cfg->park)
> + dmacr &= ~XILINX_VDMA_DMACR_CIRC_EN;
> + else
> + dmacr |= XILINX_VDMA_DMACR_CIRC_EN;
> +
> + vdma_ctrl_write(chan, XILINX_VDMA_REG_DMACR, dmacr);
> + return 0;
> + }
> +
> + /* If hsize is -1, it is interrupt threshold settings */
> + if (cfg->hsize == -1) {
> + if (cfg->coalesc <= XILINX_VDMA_DMACR_FRAME_COUNT_MAX) {
> + dmacr &= ~XILINX_VDMA_DMACR_FRAME_COUNT_MASK;
> + dmacr |= cfg->coalesc <<
> + XILINX_VDMA_DMACR_FRAME_COUNT_SHIFT;
> + chan->config.coalesc = cfg->coalesc;
> + }
> +
> + if (cfg->delay <= XILINX_VDMA_DMACR_DELAY_MAX) {
> + dmacr &= ~XILINX_VDMA_DMACR_DELAY_MASK;
> + dmacr |= cfg->delay << XILINX_VDMA_DMACR_DELAY_SHIFT;
> + chan->config.delay = cfg->delay;
> + }
> +
> + vdma_ctrl_write(chan, XILINX_VDMA_REG_DMACR, dmacr);
> + return 0;
> + }
> +
> + /* Transfer information */
> + chan->config.vsize = cfg->vsize;
> + chan->config.hsize = cfg->hsize;
> + chan->config.stride = cfg->stride;
> + chan->config.frm_dly = cfg->frm_dly;
> + chan->config.park = cfg->park;
> +
> + /* genlock settings */
> + chan->config.gen_lock = cfg->gen_lock;
> + chan->config.master = cfg->master;
> +
> + if (cfg->gen_lock && chan->genlock) {
> + dmacr |= XILINX_VDMA_DMACR_GENLOCK_EN;
> + dmacr |= cfg->master << XILINX_VDMA_DMACR_MASTER_SHIFT;
> + }
> +
> + chan->config.frm_cnt_en = cfg->frm_cnt_en;
> + if (cfg->park)
> + chan->config.park_frm = cfg->park_frm;
> + else
> + chan->config.park_frm = -1;
> +
> + chan->config.coalesc = cfg->coalesc;
> + chan->config.delay = cfg->delay;
> + if (cfg->coalesc <= XILINX_VDMA_DMACR_FRAME_COUNT_MAX) {
> + dmacr |= cfg->coalesc << XILINX_VDMA_DMACR_FRAME_COUNT_SHIFT;
> + chan->config.coalesc = cfg->coalesc;
> + }
> +
> + if (cfg->delay <= XILINX_VDMA_DMACR_DELAY_MAX) {
> + dmacr |= cfg->delay << XILINX_VDMA_DMACR_DELAY_SHIFT;
> + chan->config.delay = cfg->delay;
> + }
> +
> + /* FSync Source selection */
> + dmacr &= ~XILINX_VDMA_DMACR_FSYNCSRC_MASK;
> + dmacr |= cfg->ext_fsync << XILINX_VDMA_DMACR_FSYNCSRC_SHIFT;
> +
> + vdma_ctrl_write(chan, XILINX_VDMA_REG_DMACR, dmacr);
> + return 0;
> +}
> +
> +/**
> + * xilinx_vdma_device_control - Configure DMA channel of the device
> + * @dchan: DMA Channel pointer
> + * @cmd: DMA control command
> + * @arg: Channel configuration
> + *
> + * Return: '0' on success and failure value on error
> + */
> +static int xilinx_vdma_device_control(struct dma_chan *dchan,
> + enum dma_ctrl_cmd cmd, unsigned long arg)
> +{
> + struct xilinx_vdma_chan *chan = to_xilinx_chan(dchan);
> +
> + switch (cmd) {
> + case DMA_TERMINATE_ALL:
> + xilinx_vdma_terminate_all(chan);
> + return 0;
> + case DMA_SLAVE_CONFIG:
> + return xilinx_vdma_slave_config(chan,
> + (struct xilinx_vdma_config *)arg);
> + default:
> + return -ENXIO;
> + }
> +}
> +
> +/* -----------------------------------------------------------------------------
> + * Probe and remove
> + */
> +
> +/**
> + * xilinx_vdma_chan_remove - Per Channel remove function
> + * @chan: Driver specific VDMA channel
> + */
> +static void xilinx_vdma_chan_remove(struct xilinx_vdma_chan *chan)
> +{
> + /* Disable all interrupts */
> + vdma_ctrl_clr(chan, XILINX_VDMA_REG_DMACR,
> + XILINX_VDMA_DMAXR_ALL_IRQ_MASK);
> +
> + list_del(&chan->common.device_node);
> +}
> +
> +/**
> + * xilinx_vdma_chan_probe - Per Channel Probing
> + * It get channel features from the device tree entry and
> + * initialize special channel handling routines
> + *
> + * @xdev: Driver specific device structure
> + * @node: Device node
> + *
> + * Return: '0' on success and failure value on error
> + */
> +static int xilinx_vdma_chan_probe(struct xilinx_vdma_device *xdev,
> + struct device_node *node)
> +{
> + struct xilinx_vdma_chan *chan;
> + bool has_dre = false;
> + u32 value;
> + int err;
> +
> + /* Allocate and initialize the channel structure */
> + chan = devm_kzalloc(xdev->dev, sizeof(*chan), GFP_KERNEL);
> + if (!chan)
> + return -ENOMEM;
> +
> + chan->dev = xdev->dev;
> + chan->xdev = xdev;
> + chan->has_sg = xdev->has_sg;
> +
> + spin_lock_init(&chan->lock);
> + INIT_LIST_HEAD(&chan->pending_list);
> + INIT_LIST_HEAD(&chan->done_list);
> +
> + /* Retrieve the channel properties from the device tree */
> + has_dre = of_property_read_bool(node, "xlnx,include-dre");
> +
> + chan->genlock = of_property_read_bool(node, "xlnx,genlock-mode");
> +
> + err = of_property_read_u32(node, "xlnx,datawidth", &value);
> + if (!err) {
> + u32 width = value >> 3; /* Convert bits to bytes */
> +
> + /* If data width is greater than 8 bytes, DRE is not in hw */
> + if (width > 8)
> + has_dre = false;
> +
> + if (!has_dre)
> + xdev->common.copy_align = fls(width - 1);
> + } else {
> + dev_err(xdev->dev, "missing xlnx,datawidth property\n");
> + return err;
> + }
> +
> + if (of_device_is_compatible(node, "xlnx,axi-vdma-mm2s-channel")) {
> + chan->direction = DMA_MEM_TO_DEV;
> + chan->id = 0;
> +
> + chan->ctrl_offset = XILINX_VDMA_MM2S_CTRL_OFFSET;
> + chan->desc_offset = XILINX_VDMA_MM2S_DESC_OFFSET;
> +
> + if (xdev->flush_on_fsync == XILINX_VDMA_FLUSH_BOTH ||
> + xdev->flush_on_fsync == XILINX_VDMA_FLUSH_MM2S)
> + chan->flush_on_fsync = true;
> + } else if (of_device_is_compatible(node,
> + "xlnx,axi-vdma-s2mm-channel")) {
> + chan->direction = DMA_DEV_TO_MEM;
> + chan->id = 1;
> +
> + chan->ctrl_offset = XILINX_VDMA_S2MM_CTRL_OFFSET;
> + chan->desc_offset = XILINX_VDMA_S2MM_DESC_OFFSET;
> +
> + if (xdev->flush_on_fsync == XILINX_VDMA_FLUSH_BOTH ||
> + xdev->flush_on_fsync == XILINX_VDMA_FLUSH_S2MM)
> + chan->flush_on_fsync = true;
> + } else {
> + dev_err(xdev->dev, "Invalid channel compatible node\n");
> + return -EINVAL;
> + }
> +
> + /* Request the interrupt */
> + chan->irq = irq_of_parse_and_map(node, 0);
> + err = devm_request_irq(xdev->dev, chan->irq, xilinx_vdma_irq_handler,
> + IRQF_SHARED, "xilinx-vdma-controller", chan);
> + if (err) {
> + dev_err(xdev->dev, "unable to request IRQ\n");
> + return err;
> + }
> +
> + /* Initialize the DMA channel and add it to the DMA engine channels
> + * list.
> + */
> + chan->common.device = &xdev->common;
> +
> + list_add_tail(&chan->common.device_node, &xdev->common.channels);
> + xdev->chan[chan->id] = chan;
> +
> + /* Reset the channel */
> + err = xilinx_vdma_chan_reset(chan);
> + if (err < 0) {
> + dev_err(xdev->dev, "Reset channel failed\n");
> + return err;
> + }
> +
> + return 0;
> +}
> +
> +/**
> + * struct of_dma_filter_xilinx_args - Channel filter args
> + * @dev: DMA device structure
> + * @chan_id: Channel id
> + */
> +struct of_dma_filter_xilinx_args {
> + struct dma_device *dev;
> + u32 chan_id;
> +};
> +
> +/**
> + * xilinx_vdma_dt_filter - VDMA channel filter function
> + * @chan: DMA channel pointer
> + * @param: Filter match value
> + *
> + * Return: true/false based on the result
> + */
> +static bool xilinx_vdma_dt_filter(struct dma_chan *chan, void *param)
> +{
> + struct of_dma_filter_xilinx_args *args = param;
> +
> + return chan->device == args->dev && chan->chan_id == args->chan_id;
> +}
> +
> +/**
> + * of_dma_xilinx_xlate - Translation function
> + * @dma_spec: Pointer to DMA specifier as found in the device tree
> + * @ofdma: Pointer to DMA controller data
> + *
> + * Return: DMA channel pointer on success and NULL on error
> + */
> +static struct dma_chan *of_dma_xilinx_xlate(struct of_phandle_args *dma_spec,
> + struct of_dma *ofdma)
> +{
> + struct of_dma_filter_xilinx_args args;
> + dma_cap_mask_t cap;
> +
> + args.dev = ofdma->of_dma_data;
> + if (!args.dev)
> + return NULL;
> +
> + if (dma_spec->args_count != 1)
> + return NULL;
> +
> + dma_cap_zero(cap);
> + dma_cap_set(DMA_SLAVE, cap);
> +
> + args.chan_id = dma_spec->args[0];
> +
> + return dma_request_channel(cap, xilinx_vdma_dt_filter, &args);
> +}
> +
> +/**
> + * xilinx_vdma_probe - Driver probe function
> + * @pdev: Pointer to the platform_device structure
> + *
> + * Return: '0' on success and failure value on error
> + */
> +static int xilinx_vdma_probe(struct platform_device *pdev)
> +{
> + struct device_node *node = pdev->dev.of_node;
> + struct xilinx_vdma_device *xdev;
> + struct device_node *child;
> + struct resource *io;
> + u32 num_frames;
> + int i, err;
> +
> + dev_info(&pdev->dev, "Probing xilinx axi vdma engine\n");
> +
> + /* Allocate and initialize the DMA engine structure */
> + xdev = devm_kzalloc(&pdev->dev, sizeof(*xdev), GFP_KERNEL);
> + if (!xdev)
> + return -ENOMEM;
> +
> + xdev->dev = &pdev->dev;
> +
> + /* Request and map I/O memory */
> + io = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + xdev->regs = devm_ioremap_resource(&pdev->dev, io);
> + if (IS_ERR(xdev->regs))
> + return PTR_ERR(xdev->regs);
> +
> + /* Retrieve the DMA engine properties from the device tree */
> + xdev->has_sg = of_property_read_bool(node, "xlnx,include-sg");
> +
> + err = of_property_read_u32(node, "xlnx,num-fstores", &num_frames);
> + if (err < 0) {
> + dev_err(xdev->dev, "missing xlnx,num-fstores property\n");
> + return err;
> + }
> +
> + of_property_read_u32(node, "xlnx,flush-fsync", &xdev->flush_on_fsync);
> +
> + /* Initialize the DMA engine */
> + xdev->common.dev = &pdev->dev;
> +
> + INIT_LIST_HEAD(&xdev->common.channels);
> + dma_cap_set(DMA_SLAVE, xdev->common.cap_mask);
> + dma_cap_set(DMA_PRIVATE, xdev->common.cap_mask);
> +
> + xdev->common.device_alloc_chan_resources =
> + xilinx_vdma_alloc_chan_resources;
> + xdev->common.device_free_chan_resources =
> + xilinx_vdma_free_chan_resources;
> + xdev->common.device_prep_slave_sg = xilinx_vdma_prep_slave_sg;
> + xdev->common.device_control = xilinx_vdma_device_control;
> + xdev->common.device_tx_status = xilinx_vdma_tx_status;
> + xdev->common.device_issue_pending = xilinx_vdma_issue_pending;
> +
> + platform_set_drvdata(pdev, xdev);
> +
> + /* Initialize the channels */
> + for_each_child_of_node(node, child) {
> + err = xilinx_vdma_chan_probe(xdev, child);
> + if (err < 0)
> + goto error;
> + }
> +
> + for (i = 0; i < XILINX_VDMA_MAX_CHANS_PER_DEVICE; i++) {
> + if (xdev->chan[i])
> + xdev->chan[i]->num_frms = num_frames;
> + }
> +
> + /* Register the DMA engine with the core */
> + dma_async_device_register(&xdev->common);
> +
> + err = of_dma_controller_register(node, of_dma_xilinx_xlate,
> + &xdev->common);
> + if (err < 0) {
> + dev_err(&pdev->dev, "Unable to register DMA to DT\n");
> + dma_async_device_unregister(&xdev->common);
> + goto error;
> + }
> +
> + return 0;
> +
> +error:
> + for (i = 0; i < XILINX_VDMA_MAX_CHANS_PER_DEVICE; i++) {
> + if (xdev->chan[i])
> + xilinx_vdma_chan_remove(xdev->chan[i]);
> + }
> +
> + return err;
> +}
> +
> +/**
> + * xilinx_vdma_remove - Driver remove function
> + * @pdev: Pointer to the platform_device structure
> + *
> + * Return: Always '0'
> + */
> +static int xilinx_vdma_remove(struct platform_device *pdev)
> +{
> + struct xilinx_vdma_device *xdev;
> + int i;
> +
> + of_dma_controller_free(pdev->dev.of_node);
> +
> + xdev = platform_get_drvdata(pdev);
You could move this assignment to a variables block, it's normal
practice.
> + dma_async_device_unregister(&xdev->common);
> +
> + for (i = 0; i < XILINX_VDMA_MAX_CHANS_PER_DEVICE; i++) {
> + if (xdev->chan[i])
> + xilinx_vdma_chan_remove(xdev->chan[i]);
> + }
> +
> + return 0;
> +}
> +
> +static const struct of_device_id xilinx_vdma_of_ids[] = {
> + { .compatible = "xlnx,axi-vdma-1.00.a",},
> + {}
> +};
> +
> +static struct platform_driver xilinx_vdma_driver = {
> + .driver = {
> + .name = "xilinx-vdma",
> + .owner = THIS_MODULE,
> + .of_match_table = xilinx_vdma_of_ids,
> + },
> + .probe = xilinx_vdma_probe,
> + .remove = xilinx_vdma_remove,
> +};
> +
> +module_platform_driver(xilinx_vdma_driver);
> +
> +MODULE_AUTHOR("Xilinx, Inc.");
> +MODULE_DESCRIPTION("Xilinx VDMA driver");
> +MODULE_LICENSE("GPL v2");
> diff --git a/include/linux/amba/xilinx_dma.h b/include/linux/amba/xilinx_dma.h
> new file mode 100644
> index 0000000..48a8c8b
> --- /dev/null
> +++ b/include/linux/amba/xilinx_dma.h
> @@ -0,0 +1,50 @@
> +/*
> + * Xilinx DMA Engine drivers support header file
> + *
> + * Copyright (C) 2010-2014 Xilinx, Inc. All rights reserved.
> + *
> + * This is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + */
> +
> +#ifndef __DMA_XILINX_DMA_H
> +#define __DMA_XILINX_DMA_H
> +
> +#include <linux/dma-mapping.h>
> +#include <linux/dmaengine.h>
> +
> +/**
> + * struct xilinx_vdma_config - VDMA Configuration structure
> + * @vsize: Vertical size
> + * @hsize: Horizontal size
> + * @stride: Stride
> + * @frm_dly: Frame delay
> + * @gen_lock: Whether in gen-lock mode
> + * @master: Master that it syncs to
> + * @frm_cnt_en: Enable frame count enable
> + * @park: Whether wants to park
> + * @park_frm: Frame to park on
> + * @coalesc: Interrupt coalescing threshold
> + * @delay: Delay counter
> + * @reset: Reset Channel
> + * @ext_fsync: External Frame Sync source
> + */
> +struct xilinx_vdma_config {
> + int vsize;
> + int hsize;
> + int stride;
> + int frm_dly;
> + int gen_lock;
> + int master;
> + int frm_cnt_en;
> + int park;
> + int park_frm;
> + int coalesc;
> + int delay;
> + int reset;
> + int ext_fsync;
> +};
> +
> +#endif
--
Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Intel Finland Oy
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