Hi there, see comment below. I just did a quick compile test. Will take another look once I synthesized an image. On Mon, Aug 17, 2015 at 8:31 AM, Kedareswara rao Appana <appana.durga.rao@xxxxxxxxxx> wrote: > This is the driver for the AXI Direct Memory Access (AXI DMA) > core, which is a soft Xilinx IP core that provides high- > bandwidth direct memory access between memory and AXI4-Stream > type target peripherals. > > Signed-off-by: Srikanth Thokala <sthokal@xxxxxxxxxx> > Signed-off-by: Kedareswara rao Appana <appanad@xxxxxxxxxx> > --- > The deivce tree doc got applied in the slave-dmaengine.git. > > Forgot to include dmaengine@xxxxxxxxxxxxxxx in the cc list > resending the patch. > > Changes in v8: > - Updated the SG handling as suggested by Nicolae Rosia. > - Removed the unnecessary xilinx_dma_channel_set_config API the properties > in this API is not being used by the driver. > Changes in v7: > - Updated license in the driver as suggested by Paul. > - Corrected return value in is_idle funtion. > Changes in v6: > - Fixed Odd indention in the Kconfig. > - used GFP_NOWAIT instead of GFP_KERNEL during the desc allocation > - Calculated residue in the tx_status instead of complete_descriptor. > - Update copy right to 2015. > - Modified spin_lock handling moved the spin_lock to the appropriate functions > (instead of xilinx_dma_start_transfer doing it xilinx_dma_issue_pending api). > - device_control and declare slave caps updated as per newer APi's. > Changes in v5: > - Modified the xilinx_dma.h header file location to the > include/linux/dma/xilinx_dma.h > Changes in v4: > - Add direction field to DMA descriptor structure and removed from > channel structure to avoid duplication. > - Check for DMA idle condition before changing the configuration. > - Residue is being calculated in complete_descriptor() and is reported > to slave driver. > Changes in v3: > - Rebased on 3.16-rc7 > Changes in v2: > - Simplified the logic to set SOP and APP words in prep_slave_sg(). > - Corrected function description comments to match the return type. > - Fixed some minor comments as suggested by Andy. > > drivers/dma/Kconfig | 13 + > drivers/dma/xilinx/Makefile | 1 + > drivers/dma/xilinx/xilinx_dma.c | 1179 +++++++++++++++++++++++++++++++++++++++ > 3 files changed, 1193 insertions(+) > create mode 100644 drivers/dma/xilinx/xilinx_dma.c > > diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig > index 88d474b..5e95f07 100644 > --- a/drivers/dma/Kconfig > +++ b/drivers/dma/Kconfig > @@ -507,4 +507,17 @@ config QCOM_BAM_DMA > Enable support for the QCOM BAM DMA controller. This controller > provides DMA capabilities for a variety of on-chip devices. > > +config XILINX_DMA > + tristate "Xilinx AXI DMA Engine" > + depends on (ARCH_ZYNQ || MICROBLAZE) > + select DMA_ENGINE > + help > + Enable support for Xilinx AXI DMA Soft IP. > + > + This engine provides high-bandwidth direct memory access > + between memory and AXI4-Stream type target peripherals. > + It has two stream interfaces/channels, Memory Mapped to > + Stream (MM2S) and Stream to Memory Mapped (S2MM) for the > + data transfers. > + > endif > diff --git a/drivers/dma/xilinx/Makefile b/drivers/dma/xilinx/Makefile > index 3c4e9f2..6224a49 100644 > --- a/drivers/dma/xilinx/Makefile > +++ b/drivers/dma/xilinx/Makefile > @@ -1 +1,2 @@ > obj-$(CONFIG_XILINX_VDMA) += xilinx_vdma.o > +obj-$(CONFIG_XILINX_DMA) += xilinx_dma.o > diff --git a/drivers/dma/xilinx/xilinx_dma.c b/drivers/dma/xilinx/xilinx_dma.c > new file mode 100644 > index 0000000..a9be197 > --- /dev/null > +++ b/drivers/dma/xilinx/xilinx_dma.c > @@ -0,0 +1,1179 @@ > +/* > + * DMA driver for Xilinx DMA Engine > + * > + * Copyright (C) 2010 - 2015 Xilinx, Inc. All rights reserved. > + * > + * Based on the Freescale DMA driver. > + * > + * Description: > + * The AXI DMA, is a soft IP, which provides high-bandwidth Direct Memory > + * Access between memory and AXI4-Stream-type target peripherals. It can be > + * configured to have one channel or two channels and if configured as two > + * channels, one is to transmit data from memory to a device and another is > + * to receive from a device. > + * > + * 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. > + */ > + > +#include <linux/bitops.h> > +#include <linux/dma/xilinx_dma.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_irq.h> > +#include <linux/of_platform.h> > +#include <linux/slab.h> > + > +#include "../dmaengine.h" > + > +/* Register Offsets */ > +#define XILINX_DMA_REG_CONTROL 0x00 > +#define XILINX_DMA_REG_STATUS 0x04 > +#define XILINX_DMA_REG_CURDESC 0x08 > +#define XILINX_DMA_REG_TAILDESC 0x10 > +#define XILINX_DMA_REG_SRCADDR 0x18 > +#define XILINX_DMA_REG_DSTADDR 0x20 > +#define XILINX_DMA_REG_BTT 0x28 > + > +/* Channel/Descriptor Offsets */ > +#define XILINX_DMA_MM2S_CTRL_OFFSET 0x00 > +#define XILINX_DMA_S2MM_CTRL_OFFSET 0x30 > + > +/* General register bits definitions */ > +#define XILINX_DMA_CR_RUNSTOP_MASK BIT(0) > +#define XILINX_DMA_CR_RESET_MASK BIT(2) > + > +#define XILINX_DMA_CR_DELAY_SHIFT 24 > +#define XILINX_DMA_CR_COALESCE_SHIFT 16 > + > +#define XILINX_DMA_CR_DELAY_MAX GENMASK(7, 0) > +#define XILINX_DMA_CR_COALESCE_MAX GENMASK(7, 0) > + > +#define XILINX_DMA_SR_HALTED_MASK BIT(0) > +#define XILINX_DMA_SR_IDLE_MASK BIT(1) > + > +#define XILINX_DMA_XR_IRQ_IOC_MASK BIT(12) > +#define XILINX_DMA_XR_IRQ_DELAY_MASK BIT(13) > +#define XILINX_DMA_XR_IRQ_ERROR_MASK BIT(14) > +#define XILINX_DMA_XR_IRQ_ALL_MASK GENMASK(14, 12) > + > +/* BD definitions */ > +#define XILINX_DMA_BD_STS_ALL_MASK GENMASK(31, 28) > +#define XILINX_DMA_BD_SOP BIT(27) > +#define XILINX_DMA_BD_EOP BIT(26) > + > +/* Hw specific definitions */ > +#define XILINX_DMA_MAX_CHANS_PER_DEVICE 0x2 > +#define XILINX_DMA_MAX_TRANS_LEN GENMASK(22, 0) > + > +/* Delay loop counter to prevent hardware failure */ > +#define XILINX_DMA_LOOP_COUNT 1000000 > + > +/* Maximum number of Descriptors */ > +#define XILINX_DMA_NUM_DESCS 255 > +#define XILINX_DMA_COALESCE_MAX 255 > +#define XILINX_DMA_NUM_APP_WORDS 5 > + > +/** > + * struct xilinx_dma_desc_hw - Hardware Descriptor > + * @next_desc: Next Descriptor Pointer @0x00 > + * @pad1: Reserved @0x04 > + * @buf_addr: Buffer address @0x08 > + * @pad2: Reserved @0x0C > + * @pad3: Reserved @0x10 > + * @pad4: Reserved @0x14 > + * @control: Control field @0x18 > + * @status: Status field @0x1C > + * @app: APP Fields @0x20 - 0x30 > + */ > +struct xilinx_dma_desc_hw { > + u32 next_desc; > + u32 pad1; > + u32 buf_addr; > + u32 pad2; > + u32 pad3; > + u32 pad4; > + u32 control; > + u32 status; > + u32 app[XILINX_DMA_NUM_APP_WORDS]; > +} __aligned(64); > + > +/** > + * struct xilinx_dma_tx_segment - Descriptor segment > + * @hw: Hardware descriptor > + * @node: Node in the descriptor segments list > + * @phys: Physical address of segment > + */ > +struct xilinx_dma_tx_segment { > + struct xilinx_dma_desc_hw hw; > + struct list_head node; > + dma_addr_t phys; > +} __aligned(64); > + > +/** > + * struct xilinx_dma_tx_descriptor - Per Transaction structure > + * @async_tx: Async transaction descriptor > + * @segments: TX segments list > + * @node: Node in the channel descriptors list > + * @direction: Transfer direction > + */ > +struct xilinx_dma_tx_descriptor { > + struct dma_async_tx_descriptor async_tx; > + struct list_head segments; > + struct list_head node; > + enum dma_transfer_direction direction; > +}; > + > +/** > + * struct xilinx_dma_chan - Driver specific DMA channel structure > + * @xdev: Driver specific device structure > + * @ctrl_offset: Control registers offset > + * @ctrl_reg: Control register value > + * @lock: Descriptor operation lock > + * @pending_list: Descriptors waiting > + * @active_list: Descriptors ready to submit > + * @done_list: Complete descriptors > + * @free_seg_list: Free descriptors > + * @common: DMA common channel > + * @seg_v: Statically allocated segments base > + * @seg_p: Physical allocated segments base > + * @dev: The dma device > + * @irq: Channel IRQ > + * @id: Channel ID > + * @has_sg: Support scatter transfers > + * @idle: Check for channel idle > + * @err: Channel has errors > + * @tasklet: Cleanup work after irq > + * @residue: Residue > + * @desc_pendingcount: Descriptor pending count > + */ > +struct xilinx_dma_chan { > + struct xilinx_dma_device *xdev; > + u32 ctrl_offset; > + u32 ctrl_reg; > + spinlock_t lock; > + struct list_head pending_list; > + struct list_head done_list; > + struct list_head active_list; > + struct list_head free_seg_list; > + struct dma_chan common; > + struct xilinx_dma_tx_segment *seg_v; > + dma_addr_t seg_p; > + struct device *dev; > + int irq; > + int id; > + bool has_sg; > + bool idle; > + int err; > + struct tasklet_struct tasklet; > + u32 residue; > + u32 desc_pendingcount; > +}; > + > +/** > + * struct xilinx_dma_device - DMA device structure > + * @regs: I/O mapped base address > + * @dev: Device Structure > + * @common: DMA device structure > + * @chan: Driver specific DMA channel > + * @has_sg: Specifies whether Scatter-Gather is present or not > + */ > +struct xilinx_dma_device { > + void __iomem *regs; > + struct device *dev; > + struct dma_device common; > + struct xilinx_dma_chan *chan[XILINX_DMA_MAX_CHANS_PER_DEVICE]; > + bool has_sg; > +}; > + > +/* Macros */ > +#define to_xilinx_chan(chan) \ > + container_of(chan, struct xilinx_dma_chan, common) > +#define to_dma_tx_descriptor(tx) \ > + container_of(tx, struct xilinx_dma_tx_descriptor, async_tx) > + > +/* IO accessors */ > +static inline void dma_write(struct xilinx_dma_chan *chan, u32 reg, u32 value) > +{ > + iowrite32(value, chan->xdev->regs + reg); Any reason to not use write here? > +} > + > +static inline u32 dma_read(struct xilinx_dma_chan *chan, u32 reg) > +{ > + return ioread32(chan->xdev->regs + reg); Any reason to not use readl here? > +} > + > +static inline u32 dma_ctrl_read(struct xilinx_dma_chan *chan, u32 reg) > +{ > + return dma_read(chan, chan->ctrl_offset + reg); > +} > + > +static inline void dma_ctrl_write(struct xilinx_dma_chan *chan, u32 reg, > + u32 value) > +{ > + dma_write(chan, chan->ctrl_offset + reg, value); > +} > + > +/* ----------------------------------------------------------------------------- > + * Descriptors and segments alloc and free > + */ > + > +/** > + * xilinx_dma_alloc_tx_segment - Allocate transaction segment > + * @chan: Driver specific dma channel > + * > + * Return: The allocated segment on success and NULL on failure. > + */ > +static struct xilinx_dma_tx_segment * > +xilinx_dma_alloc_tx_segment(struct xilinx_dma_chan *chan) > +{ > + struct xilinx_dma_tx_segment *segment = NULL; > + unsigned long flags; > + > + spin_lock_irqsave(&chan->lock, flags); > + if (!list_empty(&chan->free_seg_list)) { > + segment = list_first_entry(&chan->free_seg_list, > + struct xilinx_dma_tx_segment, > + node); > + list_del(&segment->node); > + } > + spin_unlock_irqrestore(&chan->lock, flags); > + > + return segment; > +} > + > +/** > + * xilinx_dma_clean_hw_desc - Clean hardware descriptor > + * @hw: HW descriptor to clean > + */ > +static void xilinx_dma_clean_hw_desc(struct xilinx_dma_desc_hw *hw) > +{ > + u32 next_desc = hw->next_desc; > + > + memset(hw, 0, sizeof(struct xilinx_dma_desc_hw)); > + > + hw->next_desc = next_desc; > +} > + > +/** > + * xilinx_dma_free_tx_segment - Free transaction segment > + * @chan: Driver specific dma channel > + * @segment: dma transaction segment > + */ > +static void xilinx_dma_free_tx_segment(struct xilinx_dma_chan *chan, > + struct xilinx_dma_tx_segment *segment) > +{ > + xilinx_dma_clean_hw_desc(&segment->hw); > + > + list_add_tail(&segment->node, &chan->free_seg_list); > +} > + > +/** > + * xilinx_dma_tx_descriptor - Allocate transaction descriptor > + * @chan: Driver specific dma channel > + * > + * Return: The allocated descriptor on success and NULL on failure. > + */ > +static struct xilinx_dma_tx_descriptor * > +xilinx_dma_alloc_tx_descriptor(struct xilinx_dma_chan *chan) > +{ > + struct xilinx_dma_tx_descriptor *desc; > + > + desc = kzalloc(sizeof(*desc), GFP_NOWAIT); > + if (!desc) > + return NULL; > + > + INIT_LIST_HEAD(&desc->segments); > + > + return desc; > +} > + > +/** > + * xilinx_dma_free_tx_descriptor - Free transaction descriptor > + * @chan: Driver specific dma channel > + * @desc: dma transaction descriptor > + */ > +static void > +xilinx_dma_free_tx_descriptor(struct xilinx_dma_chan *chan, > + struct xilinx_dma_tx_descriptor *desc) > +{ > + struct xilinx_dma_tx_segment *segment, *next; > + > + if (!desc) > + return; > + > + list_for_each_entry_safe(segment, next, &desc->segments, node) { > + list_del(&segment->node); > + xilinx_dma_free_tx_segment(chan, segment); > + } > + > + kfree(desc); > +} > + > +/** > + * xilinx_dma_alloc_chan_resources - Allocate channel resources > + * @dchan: DMA channel > + * > + * Return: '0' on success and failure value on error > + */ > +static int xilinx_dma_alloc_chan_resources(struct dma_chan *dchan) > +{ > + struct xilinx_dma_chan *chan = to_xilinx_chan(dchan); > + int i; > + > + /* Allocate the buffer descriptors. */ > + chan->seg_v = dma_zalloc_coherent(chan->dev, > + sizeof(*chan->seg_v) * > + XILINX_DMA_NUM_DESCS, > + &chan->seg_p, GFP_KERNEL); > + if (!chan->seg_v) { > + dev_err(chan->dev, > + "unable to allocate channel %d descriptors\n", > + chan->id); > + return -ENOMEM; > + } > + > + for (i = 0; i < XILINX_DMA_NUM_DESCS; i++) { > + chan->seg_v[i].hw.next_desc = > + chan->seg_p + sizeof(*chan->seg_v) * > + ((i + 1) % XILINX_DMA_NUM_DESCS); > + chan->seg_v[i].phys = > + chan->seg_p + sizeof(*chan->seg_v) * i; > + list_add_tail(&chan->seg_v[i].node, &chan->free_seg_list); > + } > + > + dma_cookie_init(dchan); > + > + /* Enable interrupts */ > + chan->ctrl_reg |= XILINX_DMA_XR_IRQ_ALL_MASK; > + dma_ctrl_write(chan, XILINX_DMA_REG_CONTROL, chan->ctrl_reg); > + > + return 0; > +} > + > +/** > + * xilinx_dma_free_desc_list - Free descriptors list > + * @chan: Driver specific dma channel > + * @list: List to parse and delete the descriptor > + */ > +static void xilinx_dma_free_desc_list(struct xilinx_dma_chan *chan, > + struct list_head *list) > +{ > + struct xilinx_dma_tx_descriptor *desc, *next; > + > + list_for_each_entry_safe(desc, next, list, node) { > + list_del(&desc->node); > + xilinx_dma_free_tx_descriptor(chan, desc); > + } > +} > + > +/** > + * xilinx_dma_free_descriptors - Free channel descriptors > + * @chan: Driver specific dma channel > + */ > +static void xilinx_dma_free_descriptors(struct xilinx_dma_chan *chan) > +{ > + unsigned long flags; > + > + spin_lock_irqsave(&chan->lock, flags); > + > + xilinx_dma_free_desc_list(chan, &chan->pending_list); > + xilinx_dma_free_desc_list(chan, &chan->done_list); > + xilinx_dma_free_desc_list(chan, &chan->active_list); > + > + spin_unlock_irqrestore(&chan->lock, flags); > +} > + > +/** > + * xilinx_dma_free_chan_resources - Free channel resources > + * @dchan: DMA channel > + */ > +static void xilinx_dma_free_chan_resources(struct dma_chan *dchan) > +{ > + struct xilinx_dma_chan *chan = to_xilinx_chan(dchan); > + > + xilinx_dma_free_descriptors(chan); > + > + dma_free_coherent(chan->dev, > + sizeof(*chan->seg_v) * XILINX_DMA_NUM_DESCS, > + chan->seg_v, chan->seg_p); > +} > + > +/** > + * xilinx_dma_chan_desc_cleanup - Clean channel descriptors > + * @chan: Driver specific dma channel > + */ > +static void xilinx_dma_chan_desc_cleanup(struct xilinx_dma_chan *chan) > +{ > + struct xilinx_dma_tx_descriptor *desc; > + unsigned long flags; > + > + spin_lock_irqsave(&chan->lock, flags); > + > + while (!list_empty(&chan->done_list)) { > + dma_async_tx_callback callback; > + void *callback_param; > + > + desc = list_first_entry(&chan->done_list, > + struct xilinx_dma_tx_descriptor, node); > + > + /* 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_dma_free_tx_descriptor(chan, desc); > + } > + > + spin_unlock_irqrestore(&chan->lock, flags); > +} > + > +/** > + * xilinx_dma_tx_status - Get dma transaction status > + * @dchan: DMA channel > + * @cookie: Transaction identifier > + * @txstate: Transaction state > + * > + * Return: DMA transaction status > + */ > +static enum dma_status xilinx_dma_tx_status(struct dma_chan *dchan, > + dma_cookie_t cookie, > + struct dma_tx_state *txstate) > +{ > + struct xilinx_dma_chan *chan = to_xilinx_chan(dchan); > + struct xilinx_dma_tx_descriptor *desc; > + struct xilinx_dma_tx_segment *segment; > + struct xilinx_dma_desc_hw *hw; > + enum dma_status ret; > + unsigned long flags; > + u32 residue; While compiling this threw a residue may be used uninitialized warning, I suppose 0 would be a sensible default value? > + > + ret = dma_cookie_status(dchan, cookie, txstate); > + if (ret == DMA_COMPLETE || !txstate) > + return ret; > + > + desc = list_last_entry(&chan->active_list, > + struct xilinx_dma_tx_descriptor, node); > + > + spin_lock_irqsave(&chan->lock, flags); > + if (chan->has_sg) { > + while (!list_empty(&desc->segments)) { > + segment = list_first_entry(&desc->segments, > + struct xilinx_dma_tx_segment, node); > + hw = &segment->hw; > + residue += (hw->control - hw->status) & > + XILINX_DMA_MAX_TRANS_LEN; > + } > + } > + > + chan->residue = residue; > + dma_set_residue(txstate, chan->residue); > + spin_unlock_irqrestore(&chan->lock, flags); > + > + return ret; > +} > + > +/** > + * xilinx_dma_halt - Halt DMA channel > + * @chan: Driver specific DMA channel > + */ > +static void xilinx_dma_halt(struct xilinx_dma_chan *chan) > +{ > + int loop = XILINX_DMA_LOOP_COUNT; > + > + chan->ctrl_reg &= ~XILINX_DMA_CR_RUNSTOP_MASK; > + dma_ctrl_write(chan, XILINX_DMA_REG_CONTROL, chan->ctrl_reg); > + > + /* Wait for the hardware to halt */ > + do { > + if (dma_ctrl_read(chan, XILINX_DMA_REG_STATUS) & > + XILINX_DMA_SR_HALTED_MASK) > + break; > + } while (loop--); > + > + if (!loop) { > + dev_err(chan->dev, "Cannot stop channel %p: %x\n", > + chan, dma_ctrl_read(chan, XILINX_DMA_REG_STATUS)); > + chan->err = true; > + } > +} > + > +/** > + * xilinx_dma_start - Start DMA channel > + * @chan: Driver specific DMA channel > + */ > +static void xilinx_dma_start(struct xilinx_dma_chan *chan) > +{ > + int loop = XILINX_DMA_LOOP_COUNT; > + > + chan->ctrl_reg |= XILINX_DMA_CR_RUNSTOP_MASK; > + dma_ctrl_write(chan, XILINX_DMA_REG_CONTROL, chan->ctrl_reg); > + > + /* Wait for the hardware to start */ > + do { > + if (!dma_ctrl_read(chan, XILINX_DMA_REG_STATUS) & > + XILINX_DMA_SR_HALTED_MASK) > + break; > + } while (loop--); Maybe use one of the readx_poll_timeout functions? > + > + if (!loop) { > + dev_err(chan->dev, "Cannot start channel %p: %x\n", > + chan, dma_ctrl_read(chan, XILINX_DMA_REG_STATUS)); > + chan->err = true; > + } > +} > + > +/** > + * xilinx_dma_start_transfer - Starts DMA transfer > + * @chan: Driver specific channel struct pointer > + */ > +static void xilinx_dma_start_transfer(struct xilinx_dma_chan *chan) > +{ > + struct xilinx_dma_tx_descriptor *head_desc, *tail_desc; > + struct xilinx_dma_tx_segment *tail_segment; > + > + if (chan->err) > + return; > + > + if (list_empty(&chan->pending_list)) > + return; > + > + if (!chan->idle) > + return; > + > + head_desc = list_first_entry(&chan->pending_list, > + struct xilinx_dma_tx_descriptor, node); > + tail_desc = list_last_entry(&chan->pending_list, > + struct xilinx_dma_tx_descriptor, node); > + tail_segment = list_last_entry(&tail_desc->segments, > + struct xilinx_dma_tx_segment, node); > + > + if (chan->desc_pendingcount <= XILINX_DMA_COALESCE_MAX) { > + chan->ctrl_reg &= ~XILINX_DMA_CR_COALESCE_MAX; > + chan->ctrl_reg |= chan->desc_pendingcount << > + XILINX_DMA_CR_COALESCE_SHIFT; > + dma_ctrl_write(chan, XILINX_DMA_REG_CONTROL, chan->ctrl_reg); > + } > + > + if (chan->has_sg) > + dma_ctrl_write(chan, XILINX_DMA_REG_CURDESC, > + head_desc->async_tx.phys); > + > + xilinx_dma_start(chan); > + > + if (chan->err) > + return; > + > + /* Start the transfer */ > + if (chan->has_sg) { > + dma_ctrl_write(chan, XILINX_DMA_REG_TAILDESC, > + tail_segment->phys); > + } else { > + struct xilinx_dma_tx_segment *segment; > + struct xilinx_dma_desc_hw *hw; > + > + segment = list_first_entry(&head_desc->segments, > + struct xilinx_dma_tx_segment, node); > + hw = &segment->hw; > + > + if (head_desc->direction == DMA_MEM_TO_DEV) > + dma_ctrl_write(chan, XILINX_DMA_REG_SRCADDR, > + hw->buf_addr); > + else > + dma_ctrl_write(chan, XILINX_DMA_REG_DSTADDR, > + hw->buf_addr); > + > + /* Start the transfer */ > + dma_ctrl_write(chan, XILINX_DMA_REG_BTT, > + hw->control & XILINX_DMA_MAX_TRANS_LEN); > + } > + > + list_splice_tail_init(&chan->pending_list, &chan->active_list); > + chan->desc_pendingcount = 0; > + chan->idle = false; > +} > + > +/** > + * xilinx_dma_issue_pending - Issue pending transactions > + * @dchan: DMA channel > + */ > +static void xilinx_dma_issue_pending(struct dma_chan *dchan) > +{ > + struct xilinx_dma_chan *chan = to_xilinx_chan(dchan); > + unsigned long flags; > + > + spin_lock_irqsave(&chan->lock, flags); > + xilinx_dma_start_transfer(chan); > + spin_unlock_irqrestore(&chan->lock, flags); > +} > + > +/** > + * xilinx_dma_complete_descriptor - Mark the active descriptor as complete > + * @chan : xilinx DMA channel > + */ > +static void xilinx_dma_complete_descriptor(struct xilinx_dma_chan *chan) > +{ > + struct xilinx_dma_tx_descriptor *desc, *next; > + > + if (list_empty(&chan->active_list)) > + return; > + > + list_for_each_entry_safe(desc, next, &chan->active_list, node) { > + list_del(&desc->node); > + dma_cookie_complete(&desc->async_tx); > + list_add_tail(&desc->node, &chan->done_list); > + } > +} > + > +/** > + * xilinx_dma_reset - Reset DMA channel > + * @chan: Driver specific DMA channel > + * > + * Return: '0' on success and failure value on error > + */ > +static int xilinx_dma_chan_reset(struct xilinx_dma_chan *chan) > +{ > + int loop = XILINX_DMA_LOOP_COUNT; > + u32 tmp; > + > + chan->ctrl_reg = dma_ctrl_read(chan, XILINX_DMA_REG_CONTROL); > + dma_ctrl_write(chan, XILINX_DMA_REG_CONTROL, chan->ctrl_reg | > + XILINX_DMA_CR_RESET_MASK); > + > + tmp = dma_ctrl_read(chan, XILINX_DMA_REG_CONTROL) & > + XILINX_DMA_CR_RESET_MASK; > + > + /* Wait for the hardware to finish reset */ > + do { > + tmp = dma_ctrl_read(chan, XILINX_DMA_REG_CONTROL) & > + XILINX_DMA_CR_RESET_MASK; > + } while (loop-- && tmp); See above > + > + if (!loop) { > + dev_err(chan->dev, "reset timeout, cr %x, sr %x\n", > + dma_ctrl_read(chan, XILINX_DMA_REG_CONTROL), > + dma_ctrl_read(chan, XILINX_DMA_REG_STATUS)); > + return -EBUSY; > + } > + > + chan->err = false; > + > + return 0; > +} > + > +/** > + * xilinx_dma_irq_handler - DMA Interrupt handler > + * @irq: IRQ number > + * @data: Pointer to the Xilinx DMA channel structure > + * > + * Return: IRQ_HANDLED/IRQ_NONE > + */ > +static irqreturn_t xilinx_dma_irq_handler(int irq, void *data) > +{ > + struct xilinx_dma_chan *chan = data; > + u32 status; > + > + /* Read the status and ack the interrupts. */ > + status = dma_ctrl_read(chan, XILINX_DMA_REG_STATUS); > + if (!(status & XILINX_DMA_XR_IRQ_ALL_MASK)) > + return IRQ_NONE; > + > + dma_ctrl_write(chan, XILINX_DMA_REG_STATUS, > + status & XILINX_DMA_XR_IRQ_ALL_MASK); > + > + if (status & XILINX_DMA_XR_IRQ_ERROR_MASK) { > + dev_err(chan->dev, > + "Channel %p has errors %x, cdr %x tdr %x\n", > + chan, dma_ctrl_read(chan, XILINX_DMA_REG_STATUS), > + dma_ctrl_read(chan, XILINX_DMA_REG_CURDESC), > + dma_ctrl_read(chan, XILINX_DMA_REG_TAILDESC)); > + chan->err = true; > + } > + > + /* > + * Device takes too long to do the transfer when user requires > + * responsiveness > + */ > + if (status & XILINX_DMA_XR_IRQ_DELAY_MASK) > + dev_dbg(chan->dev, "Inter-packet latency too long\n"); > + > + if (status & XILINX_DMA_XR_IRQ_IOC_MASK) { > + spin_lock(&chan->lock); > + xilinx_dma_complete_descriptor(chan); > + chan->idle = true; > + xilinx_dma_start_transfer(chan); > + spin_unlock(&chan->lock); > + } > + > + tasklet_schedule(&chan->tasklet); > + return IRQ_HANDLED; > +} > + > +/** > + * xilinx_dma_do_tasklet - Schedule completion tasklet > + * @data: Pointer to the Xilinx dma channel structure > + */ > +static void xilinx_dma_do_tasklet(unsigned long data) > +{ > + struct xilinx_dma_chan *chan = (struct xilinx_dma_chan *)data; > + > + xilinx_dma_chan_desc_cleanup(chan); > +} > + > +/** > + * append_desc_queue - Queuing descriptor > + * @chan: Driver specific dma channel > + * @desc: dma transaction descriptor > + */ > +static void append_desc_queue(struct xilinx_dma_chan *chan, > + struct xilinx_dma_tx_descriptor *desc) > +{ > + struct xilinx_dma_tx_segment *tail_segment; > + struct xilinx_dma_tx_descriptor *tail_desc; > + > + if (list_empty(&chan->pending_list)) > + goto append; > + > + /* > + * Add the hardware descriptor to the chain of hardware descriptors > + * that already exists in memory. > + */ > + tail_desc = list_last_entry(&chan->pending_list, > + struct xilinx_dma_tx_descriptor, node); > + tail_segment = list_last_entry(&tail_desc->segments, > + struct xilinx_dma_tx_segment, node); > + tail_segment->hw.next_desc = (u32)desc->async_tx.phys; > + > + /* > + * Add the software descriptor and all children to the list > + * of pending transactions > + */ > +append: > + list_add_tail(&desc->node, &chan->pending_list); > + chan->desc_pendingcount++; > + > + if (unlikely(chan->desc_pendingcount > XILINX_DMA_COALESCE_MAX)) { > + dev_dbg(chan->dev, "desc pendingcount is too high\n"); > + chan->desc_pendingcount = XILINX_DMA_COALESCE_MAX; > + BUG(); > + } > +} > + > +/** > + * xilinx_dma_tx_submit - Submit DMA transaction > + * @tx: Async transaction descriptor > + * > + * Return: cookie value on success and failure value on error > + */ > +static dma_cookie_t xilinx_dma_tx_submit(struct dma_async_tx_descriptor *tx) > +{ > + struct xilinx_dma_tx_descriptor *desc = to_dma_tx_descriptor(tx); > + struct xilinx_dma_chan *chan = to_xilinx_chan(tx->chan); > + 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_dma_chan_reset(chan); > + if (err < 0) > + return err; > + } > + > + spin_lock_irqsave(&chan->lock, flags); > + > + cookie = dma_cookie_assign(tx); > + > + /* Put this transaction onto the tail of the pending queue */ > + append_desc_queue(chan, desc); > + > + spin_unlock_irqrestore(&chan->lock, flags); > + > + return cookie; > +} > + > +/** > + * xilinx_dma_prep_slave_sg - prepare descriptors for a DMA_SLAVE transaction > + * @dchan: DMA channel > + * @sgl: scatterlist to transfer to/from > + * @sg_len: number of entries in @scatterlist > + * @direction: DMA direction > + * @flags: transfer ack flags > + * @context: APP words of the descriptor > + * > + * Return: Async transaction descriptor on success and NULL on failure > + */ > +static struct dma_async_tx_descriptor *xilinx_dma_prep_slave_sg( > + struct dma_chan *dchan, struct scatterlist *sgl, unsigned int sg_len, > + enum dma_transfer_direction direction, unsigned long flags, > + void *context) > +{ > + struct xilinx_dma_chan *chan = to_xilinx_chan(dchan); > + struct xilinx_dma_tx_descriptor *desc; > + struct xilinx_dma_tx_segment *segment; > + u32 *app_w = (u32 *)context; > + struct scatterlist *sg; > + size_t copy, sg_used; > + int i; > + > + if (!is_slave_direction(direction)) > + return NULL; > + > + /* Allocate a transaction descriptor. */ > + desc = xilinx_dma_alloc_tx_descriptor(chan); > + if (!desc) > + return NULL; > + > + desc->direction = direction; > + dma_async_tx_descriptor_init(&desc->async_tx, &chan->common); > + desc->async_tx.tx_submit = xilinx_dma_tx_submit; > + > + /* Build transactions using information in the scatter gather list */ > + for_each_sg(sgl, sg, sg_len, i) { > + sg_used = 0; > + > + /* Loop until the entire scatterlist entry is used */ > + while (sg_used < sg_dma_len(sg)) { > + struct xilinx_dma_desc_hw *hw; > + > + /* Get a free segment */ > + segment = xilinx_dma_alloc_tx_segment(chan); > + if (!segment) > + goto error; > + > + /* > + * Calculate the maximum number of bytes to transfer, > + * making sure it is less than the hw limit > + */ > + copy = min_t(size_t, sg_dma_len(sg) - sg_used, > + XILINX_DMA_MAX_TRANS_LEN); > + hw = &segment->hw; > + > + /* Fill in the descriptor */ > + hw->buf_addr = sg_dma_address(sg) + sg_used; > + > + hw->control = copy; > + > + if (direction == DMA_MEM_TO_DEV) { > + if (app_w) > + memcpy(hw->app, app_w, sizeof(u32) * > + XILINX_DMA_NUM_APP_WORDS); > + } > + > + sg_used += copy; > + > + /* > + * Insert the segment into the descriptor segments > + * list. > + */ > + list_add_tail(&segment->node, &desc->segments); > + } > + } > + > + segment = list_first_entry(&desc->segments, > + struct xilinx_dma_tx_segment, node); > + desc->async_tx.phys = segment->phys; > + > + /* For the last DMA_MEM_TO_DEV transfer, set EOP */ > + if (direction == DMA_MEM_TO_DEV) { > + segment->hw.control |= XILINX_DMA_BD_SOP; > + segment = list_last_entry(&desc->segments, > + struct xilinx_dma_tx_segment, > + node); > + segment->hw.control |= XILINX_DMA_BD_EOP; > + } > + > + return &desc->async_tx; > + > +error: > + xilinx_dma_free_tx_descriptor(chan, desc); > + return NULL; > +} > + > +/** > + * xilinx_dma_terminate_all - Halt the channel and free descriptors > + * @dchan: DMA Channel pointer > + * > + * Return: '0' always > + */ > +static int xilinx_dma_terminate_all(struct dma_chan *dchan) > +{ > + struct xilinx_dma_chan *chan = to_xilinx_chan(dchan); > + > + /* Halt the DMA engine */ > + xilinx_dma_halt(chan); > + > + /* Remove and free all of the descriptors in the lists */ > + xilinx_dma_free_descriptors(chan); > + > + return 0; > +} > + > +/** > + * xilinx_dma_chan_remove - Per Channel remove function > + * @chan: Driver specific DMA channel > + */ > +static void xilinx_dma_chan_remove(struct xilinx_dma_chan *chan) > +{ > + /* Disable interrupts */ > + chan->ctrl_reg &= ~XILINX_DMA_XR_IRQ_ALL_MASK; > + dma_ctrl_write(chan, XILINX_DMA_REG_CONTROL, chan->ctrl_reg); > + > + if (chan->irq > 0) > + free_irq(chan->irq, chan); > + > + tasklet_kill(&chan->tasklet); > + > + list_del(&chan->common.device_node); > +} > + > +/** > + * xilinx_dma_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_dma_chan_probe(struct xilinx_dma_device *xdev, > + struct device_node *node) > +{ > + struct xilinx_dma_chan *chan; > + int err; > + bool has_dre; > + u32 value, width = 0; > + > + /* alloc channel */ > + 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; > + chan->desc_pendingcount = 0x0; > + > + has_dre = of_property_read_bool(node, "xlnx,include-dre"); > + > + err = of_property_read_u32(node, "xlnx,datawidth", &value); > + if (err) { > + dev_err(xdev->dev, "unable to read datawidth property"); > + return err; > + } > + > + 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); > + > + if (of_device_is_compatible(node, "xlnx,axi-dma-mm2s-channel")) { > + chan->id = 0; > + chan->ctrl_offset = XILINX_DMA_MM2S_CTRL_OFFSET; > + } else if (of_device_is_compatible(node, "xlnx,axi-dma-s2mm-channel")) { > + chan->id = 1; > + chan->ctrl_offset = XILINX_DMA_S2MM_CTRL_OFFSET; > + } else { > + dev_err(xdev->dev, "Invalid channel compatible node\n"); > + return -EINVAL; > + } > + > + xdev->chan[chan->id] = chan; > + > + /* Initialize the channel */ > + err = xilinx_dma_chan_reset(chan); > + if (err) { > + dev_err(xdev->dev, "Reset channel failed\n"); > + return err; > + } > + > + spin_lock_init(&chan->lock); > + INIT_LIST_HEAD(&chan->pending_list); > + INIT_LIST_HEAD(&chan->done_list); > + INIT_LIST_HEAD(&chan->active_list); > + INIT_LIST_HEAD(&chan->free_seg_list); > + > + chan->common.device = &xdev->common; > + > + /* find the IRQ line, if it exists in the device tree */ > + chan->irq = irq_of_parse_and_map(node, 0); > + err = request_irq(chan->irq, xilinx_dma_irq_handler, > + IRQF_SHARED, > + "xilinx-dma-controller", chan); > + if (err) { > + dev_err(xdev->dev, "unable to request IRQ %d\n", chan->irq); > + return err; > + } > + > + /* Initialize the tasklet */ > + tasklet_init(&chan->tasklet, xilinx_dma_do_tasklet, > + (unsigned long)chan); > + > + /* Add the channel to DMA device channel list */ > + list_add_tail(&chan->common.device_node, &xdev->common.channels); > + > + chan->idle = true; > + > + return 0; > +} > + > +/** > + * 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 xilinx_dma_device *xdev = ofdma->of_dma_data; > + int chan_id = dma_spec->args[0]; > + > + if (chan_id >= XILINX_DMA_MAX_CHANS_PER_DEVICE) > + return NULL; > + > + return dma_get_slave_channel(&xdev->chan[chan_id]->common); > +} > + > +/** > + * xilinx_dma_probe - Driver probe function > + * @pdev: Pointer to the platform_device structure > + * > + * Return: '0' on success and failure value on error > + */ > +static int xilinx_dma_probe(struct platform_device *pdev) > +{ > + struct xilinx_dma_device *xdev; > + struct device_node *child, *node; > + struct resource *res; > + int i, ret; > + > + xdev = devm_kzalloc(&pdev->dev, sizeof(*xdev), GFP_KERNEL); > + if (!xdev) > + return -ENOMEM; > + > + xdev->dev = &(pdev->dev); > + INIT_LIST_HEAD(&xdev->common.channels); > + > + node = pdev->dev.of_node; > + > + /* Map the registers */ > + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); > + xdev->regs = devm_ioremap_resource(&pdev->dev, res); > + if (IS_ERR(xdev->regs)) > + return PTR_ERR(xdev->regs); > + > + /* Check if SG is enabled */ > + xdev->has_sg = of_property_read_bool(node, "xlnx,include-sg"); > + > + /* Axi DMA only do slave transfers */ > + dma_cap_set(DMA_SLAVE, xdev->common.cap_mask); > + dma_cap_set(DMA_PRIVATE, xdev->common.cap_mask); > + xdev->common.device_prep_slave_sg = xilinx_dma_prep_slave_sg; > + xdev->common.device_terminate_all = xilinx_dma_terminate_all; > + xdev->common.device_issue_pending = xilinx_dma_issue_pending; > + xdev->common.device_alloc_chan_resources = > + xilinx_dma_alloc_chan_resources; > + xdev->common.device_free_chan_resources = > + xilinx_dma_free_chan_resources; > + xdev->common.device_tx_status = xilinx_dma_tx_status; > + xdev->common.directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV); > + xdev->common.residue_granularity = DMA_RESIDUE_GRANULARITY_SEGMENT; > + xdev->common.dev = &pdev->dev; > + > + platform_set_drvdata(pdev, xdev); > + > + for_each_child_of_node(node, child) { > + ret = xilinx_dma_chan_probe(xdev, child); > + if (ret) { > + dev_err(&pdev->dev, "Probing channels failed\n"); > + goto free_chan_resources; > + } > + } > + > + dma_async_device_register(&xdev->common); > + > + ret = of_dma_controller_register(node, of_dma_xilinx_xlate, xdev); > + if (ret) { > + dev_err(&pdev->dev, "Unable to register DMA to DT\n"); > + dma_async_device_unregister(&xdev->common); > + goto free_chan_resources; > + } > + > + dev_info(&pdev->dev, "Xilinx AXI DMA Engine driver Probed!!\n"); > + > + return 0; > + > +free_chan_resources: > + for (i = 0; i < XILINX_DMA_MAX_CHANS_PER_DEVICE; i++) > + if (xdev->chan[i]) > + xilinx_dma_chan_remove(xdev->chan[i]); > + > + return ret; > +} > + > +/** > + * xilinx_dma_remove - Driver remove function > + * @pdev: Pointer to the platform_device structure > + * > + * Return: Always '0' > + */ > +static int xilinx_dma_remove(struct platform_device *pdev) > +{ > + struct xilinx_dma_device *xdev = platform_get_drvdata(pdev); > + int i; > + > + of_dma_controller_free(pdev->dev.of_node); > + dma_async_device_unregister(&xdev->common); > + > + for (i = 0; i < XILINX_DMA_MAX_CHANS_PER_DEVICE; i++) > + if (xdev->chan[i]) > + xilinx_dma_chan_remove(xdev->chan[i]); > + > + return 0; > +} > + > +static const struct of_device_id xilinx_dma_of_match[] = { > + { .compatible = "xlnx,axi-dma-1.00.a",}, > + {} > +}; > +MODULE_DEVICE_TABLE(of, xilinx_dma_of_match); > + > +static struct platform_driver xilinx_dma_driver = { > + .driver = { > + .name = "xilinx-dma", > + .of_match_table = xilinx_dma_of_match, > + }, > + .probe = xilinx_dma_probe, > + .remove = xilinx_dma_remove, > +}; > + > +module_platform_driver(xilinx_dma_driver); > + > +MODULE_AUTHOR("Xilinx, Inc."); > +MODULE_DESCRIPTION("Xilinx DMA driver"); > +MODULE_LICENSE("GPL"); > -- > 2.1.2 > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel Cheers, Moritz -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html