This driver adds support for the Altera / Intel modular Scatter-Gather
Direct Memory Access (mSGDMA) intellectual property (IP) to the Linux
DMAengine subsystem. Currently it supports the following op modes:
- DMA_MEMCPY
- DMA_SG
- DMA_SLAVE
This implementation has been tested on an Altera Cyclone FPGA connected
via PCIe, both on an ARM and an x86 platform.
Signed-off-by: Stefan Roese <sr@xxxxxxx>
Cc: Vinod Koul <vinod.koul@xxxxxxxxx>
---
v3:
- Use GENMASK for some macros as suggested by Vinod
- Simplify logic in descriptor loop in msgdma_prep_slave_sg() -
drop goto statement
- Use kcalloc instead of kzalloc
- Move submission of new desriptors in idle state from tasklet
to the interrupt handler
v2:
- Add support for 64bit DMA by using dma_set_mask_and_coherent()
- Use kernel-doc style comments for struct declatations
- Remove some unused macros
- Remove unused code in msgdma_tx_submit()
- Remove check for "len > MSGDMA_MAX_TRANS_LEN" as its not needed.
If the length is longer, the transfer is split up into multiple
parts already
- Chance indentation of function parameters as suggested by Vinod
- Add comments, why the last controler word is written seperately
in msgdma_copy_one() and add some memory write barriers
- Change GFP_KERNEL to GFP_NOWAIT
- Use dev_dbg instead of pr_debug()
- Add logic to detect idle controller state and submit next descriptor
in irq handler, if idle is detected
- Add MODULE_ALIAS
drivers/dma/Kconfig | 6 +
drivers/dma/Makefile | 1 +
drivers/dma/altera-msgdma.c | 1031 +++++++++++++++++++++++++++++++++++++++++++
3 files changed, 1038 insertions(+)
create mode 100644 drivers/dma/altera-msgdma.c
diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
index 24e8597b2c3e..1d26b5734369 100644
--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -56,6 +56,12 @@ config DMA_OF
select DMA_ENGINE
#devices
+config ALTERA_MSGDMA
+ tristate "Altera / Intel mSGDMA Engine"
+ select DMA_ENGINE
+ help
+ Enable support for Altera / Intel mSGDMA controller.
+
config AMBA_PL08X
bool "ARM PrimeCell PL080 or PL081 support"
depends on ARM_AMBA
diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
index 0b723e94d9e6..cf68b1dae0bf 100644
--- a/drivers/dma/Makefile
+++ b/drivers/dma/Makefile
@@ -12,6 +12,7 @@ obj-$(CONFIG_DMA_OF) += of-dma.o
obj-$(CONFIG_DMATEST) += dmatest.o
#devices
+obj-$(CONFIG_ALTERA_MSGDMA) += altera-msgdma.o
obj-$(CONFIG_AMBA_PL08X) += amba-pl08x.o
obj-$(CONFIG_AMCC_PPC440SPE_ADMA) += ppc4xx/
obj-$(CONFIG_AT_HDMAC) += at_hdmac.o
diff --git a/drivers/dma/altera-msgdma.c b/drivers/dma/altera-msgdma.c
new file mode 100644
index 000000000000..33b87b413793
--- /dev/null
+++ b/drivers/dma/altera-msgdma.c
@@ -0,0 +1,1031 @@
+/*
+ * DMA driver for Altera mSGDMA IP core
+ *
+ * Copyright (C) 2017 Stefan Roese <sr@xxxxxxx>
+ *
+ * Based on drivers/dma/xilinx/zynqmp_dma.c, which is:
+ * Copyright (C) 2016 Xilinx, Inc. All rights reserved.
+ *
+ * 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/bitops.h>
+#include <linux/delay.h>
+#include <linux/dma-mapping.h>
+#include <linux/dmapool.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+#include "dmaengine.h"
+
+#define MSGDMA_MAX_TRANS_LEN U32_MAX
+#define MSGDMA_DESC_NUM 1024
+
+/**
+ * struct msgdma_extended_desc - implements an extended descriptor
+ * @read_addr_lo: data buffer source address low bits
+ * @write_addr_lo: data buffer destination address low bits
+ * @len: the number of bytes to transfer per descriptor
+ * @burst_seq_num: bit 31:24 write burst
+ * bit 23:16 read burst
+ * bit 15:00 sequence number
+ * @stride: bit 31:16 write stride
+ * bit 15:00 read stride
+ * @read_addr_hi: data buffer source address high bits
+ * @write_addr_hi: data buffer destination address high bits
+ * @control: characteristics of the transfer
+ */
+struct msgdma_extended_desc {
+ u32 read_addr_lo;
+ u32 write_addr_lo;
+ u32 len;
+ u32 burst_seq_num;
+ u32 stride;
+ u32 read_addr_hi;
+ u32 write_addr_hi;
+ u32 control;
+};
+
+/* mSGDMA descriptor control field bit definitions */
+#define MSGDMA_DESC_CTL_SET_CH(x) ((x) & 0xff)
+#define MSGDMA_DESC_CTL_GEN_SOP BIT(8)
+#define MSGDMA_DESC_CTL_GEN_EOP BIT(9)
+#define MSGDMA_DESC_CTL_PARK_READS BIT(10)
+#define MSGDMA_DESC_CTL_PARK_WRITES BIT(11)
+#define MSGDMA_DESC_CTL_END_ON_EOP BIT(12)
+#define MSGDMA_DESC_CTL_END_ON_LEN BIT(13)
+#define MSGDMA_DESC_CTL_TR_COMP_IRQ BIT(14)
+#define MSGDMA_DESC_CTL_EARLY_IRQ BIT(15)
+#define MSGDMA_DESC_CTL_TR_ERR_IRQ GENMASK(23, 16)
+#define MSGDMA_DESC_CTL_EARLY_DONE BIT(24)
+
+/*
+ * Writing "1" the "go" bit commits the entire descriptor into the
+ * descriptor FIFO(s)
+ */
+#define MSGDMA_DESC_CTL_GO BIT(31)
+
+/* Tx buffer control flags */
+#define MSGDMA_DESC_CTL_TX_FIRST (MSGDMA_DESC_CTL_GEN_SOP | \
+ MSGDMA_DESC_CTL_TR_ERR_IRQ | \
+ MSGDMA_DESC_CTL_GO)
+
+#define MSGDMA_DESC_CTL_TX_MIDDLE (MSGDMA_DESC_CTL_TR_ERR_IRQ | \
+ MSGDMA_DESC_CTL_GO)
+
+#define MSGDMA_DESC_CTL_TX_LAST (MSGDMA_DESC_CTL_GEN_EOP | \
+ MSGDMA_DESC_CTL_TR_COMP_IRQ | \
+ MSGDMA_DESC_CTL_TR_ERR_IRQ | \
+ MSGDMA_DESC_CTL_GO)
+
+#define MSGDMA_DESC_CTL_TX_SINGLE (MSGDMA_DESC_CTL_GEN_SOP | \
+ MSGDMA_DESC_CTL_GEN_EOP | \
+ MSGDMA_DESC_CTL_TR_COMP_IRQ | \
+ MSGDMA_DESC_CTL_TR_ERR_IRQ | \
+ MSGDMA_DESC_CTL_GO)
+
+#define MSGDMA_DESC_CTL_RX_SINGLE (MSGDMA_DESC_CTL_END_ON_EOP | \
+ MSGDMA_DESC_CTL_END_ON_LEN | \
+ MSGDMA_DESC_CTL_TR_COMP_IRQ | \
+ MSGDMA_DESC_CTL_EARLY_IRQ | \
+ MSGDMA_DESC_CTL_TR_ERR_IRQ | \
+ MSGDMA_DESC_CTL_GO)
+
+/* mSGDMA extended descriptor stride definitions */
+#define MSGDMA_DESC_STRIDE_RD 0x00000001
+#define MSGDMA_DESC_STRIDE_WR 0x00010000
+#define MSGDMA_DESC_STRIDE_RW 0x00010001
+
+/**
+ * struct msgdma_csr - mSGDMA dispatcher control and status register map
+ * @status: Read/Clear
+ * @control: Read/Write
+ * @rw_fill_level: bit 31:16 - write fill level
+ * bit 15:00 - read fill level
+ * @resp_fill_level: bit 15:00 - response FIFO fill level
+ * @rw_seq_num: bit 31:16 - write sequence number
+ * bit 15:00 - read sequence number
+ * @pad: reserved
+ */
+struct msgdma_csr {
+ u32 status;
+ u32 control;
+ u32 rw_fill_level;
+ u32 resp_fill_level;
+ u32 rw_seq_num;
+ u32 pad[3];
+};
+
+/* mSGDMA CSR status register bit definitions */
+#define MSGDMA_CSR_STAT_BUSY BIT(0)
+#define MSGDMA_CSR_STAT_DESC_BUF_EMPTY BIT(1)
+#define MSGDMA_CSR_STAT_DESC_BUF_FULL BIT(2)
+#define MSGDMA_CSR_STAT_RESP_BUF_EMPTY BIT(3)
+#define MSGDMA_CSR_STAT_RESP_BUF_FULL BIT(4)
+#define MSGDMA_CSR_STAT_STOPPED BIT(5)
+#define MSGDMA_CSR_STAT_RESETTING BIT(6)
+#define MSGDMA_CSR_STAT_STOPPED_ON_ERR BIT(7)
+#define MSGDMA_CSR_STAT_STOPPED_ON_EARLY BIT(8)
+#define MSGDMA_CSR_STAT_IRQ BIT(9)
+#define MSGDMA_CSR_STAT_MASK GENMASK(9, 0)
+#define MSGDMA_CSR_STAT_MASK_WITHOUT_IRQ GENMASK(8, 0)
+
+#define DESC_EMPTY (MSGDMA_CSR_STAT_DESC_BUF_EMPTY | \
+ MSGDMA_CSR_STAT_RESP_BUF_EMPTY)
+
+/* mSGDMA CSR control register bit definitions */
+#define MSGDMA_CSR_CTL_STOP BIT(0)
+#define MSGDMA_CSR_CTL_RESET BIT(1)
+#define MSGDMA_CSR_CTL_STOP_ON_ERR BIT(2)
+#define MSGDMA_CSR_CTL_STOP_ON_EARLY BIT(3)
+#define MSGDMA_CSR_CTL_GLOBAL_INTR BIT(4)
+#define MSGDMA_CSR_CTL_STOP_DESCS BIT(5)
+
+/* mSGDMA CSR fill level bits */
+#define MSGDMA_CSR_WR_FILL_LEVEL_GET(v) (((v) & 0xffff0000) >> 16)
+#define MSGDMA_CSR_RD_FILL_LEVEL_GET(v) ((v) & 0x0000ffff)
+#define MSGDMA_CSR_RESP_FILL_LEVEL_GET(v) ((v) & 0x0000ffff)
+
+#define MSGDMA_CSR_SEQ_NUM_GET(v) (((v) & 0xffff0000) >> 16)
+
+/* mSGDMA response register map */
+struct msgdma_response {
+ u32 bytes_transferred;
+ u32 status;
+};
+
+/* mSGDMA response register bit definitions */
+#define MSGDMA_RESP_EARLY_TERM BIT(8)
+#define MSGDMA_RESP_ERR_MASK 0xff
+
+/**
+ * struct msgdma_sw_desc - implements a sw descriptor
+ * @async_tx: support for the async_tx api
+ * @hw_desc: assosiated HW descriptor
+ * @free_list: node of the free SW descriprots list
+ */
+struct msgdma_sw_desc {
+ struct dma_async_tx_descriptor async_tx;
+ struct msgdma_extended_desc hw_desc;
+ struct list_head node;
+ struct list_head tx_list;
+};
+
+/**
+ * struct msgdma_device - DMA device structure
+ */
+struct msgdma_device {
+ spinlock_t lock;
+ struct device *dev;
+ struct tasklet_struct irq_tasklet;
+ struct list_head pending_list;
+ struct list_head free_list;
+ struct list_head active_list;
+ struct list_head done_list;
+ u32 desc_free_cnt;
+ bool idle;
+
+ struct dma_device dmadev;
+ struct dma_chan dmachan;
+ dma_addr_t hw_desq;
+ struct msgdma_sw_desc *sw_desq;
+ unsigned int npendings;
+
+ struct dma_slave_config slave_cfg;
+
+ int irq;
+
+ /* mSGDMA controller */
+ struct msgdma_csr *csr;
+
+ /* mSGDMA descriptors */
+ struct msgdma_extended_desc *desc;
+
+ /* mSGDMA response */
+ struct msgdma_response *resp;
+};
+
+#define to_mdev(chan) container_of(chan, struct msgdma_device, dmachan)
+#define tx_to_desc(tx) container_of(tx, struct msgdma_sw_desc, async_tx)
+
+/**
+ * msgdma_get_descriptor - Get the sw descriptor from the pool
+ * @mdev: Pointer to the Altera mSGDMA device structure
+ *
+ * Return: The sw descriptor
+ */
+static struct msgdma_sw_desc *msgdma_get_descriptor(struct msgdma_device *mdev)
+{
+ struct msgdma_sw_desc *desc;
+
+ spin_lock_bh(&mdev->lock);
+ desc = list_first_entry(&mdev->free_list, struct msgdma_sw_desc, node);
+ list_del(&desc->node);
+ spin_unlock_bh(&mdev->lock);
+
+ INIT_LIST_HEAD(&desc->tx_list);
+
+ return desc;
+}
+
+/**
+ * msgdma_free_descriptor - Issue pending transactions
+ * @mdev: Pointer to the Altera mSGDMA device structure
+ * @desc: Transaction descriptor pointer
+ */
+static void msgdma_free_descriptor(struct msgdma_device *mdev,
+ struct msgdma_sw_desc *desc)
+{
+ struct msgdma_sw_desc *child, *next;
+
+ mdev->desc_free_cnt++;
+ list_add_tail(&desc->node, &mdev->free_list);
+ list_for_each_entry_safe(child, next, &desc->tx_list, node) {
+ mdev->desc_free_cnt++;
+ list_move_tail(&child->node, &mdev->free_list);
+ }
+}
+
+/**
+ * msgdma_free_desc_list - Free descriptors list
+ * @mdev: Pointer to the Altera mSGDMA device structure
+ * @list: List to parse and delete the descriptor
+ */
+static void msgdma_free_desc_list(struct msgdma_device *mdev,
+ struct list_head *list)
+{
+ struct msgdma_sw_desc *desc, *next;
+
+ list_for_each_entry_safe(desc, next, list, node)
+ msgdma_free_descriptor(mdev, desc);
+}
+
+/**
+ * msgdma_desc_config - Configure the descriptor
+ * @desc: Hw descriptor pointer
+ * @dst: Destination buffer address
+ * @src: Source buffer address
+ * @len: Transfer length
+ */
+static void msgdma_desc_config(struct msgdma_extended_desc *desc,
+ dma_addr_t dst, dma_addr_t src, size_t len,
+ u32 stride)
+{
+ /* Set lower 32bits of src & dst addresses in the descriptor */
+ desc->read_addr_lo = lower_32_bits(src);
+ desc->write_addr_lo = lower_32_bits(dst);
+
+ /* Set upper 32bits of src & dst addresses in the descriptor */
+ desc->read_addr_hi = upper_32_bits(src);
+ desc->write_addr_hi = upper_32_bits(dst);
+
+ desc->len = len;
+ desc->stride = stride;
+ desc->burst_seq_num = 0; /* 0 will result in max burst length */
+
+ /*
+ * Don't set interrupt on xfer end yet, this will be done later
+ * for the "last" descriptor
+ */
+ desc->control = MSGDMA_DESC_CTL_TR_ERR_IRQ | MSGDMA_DESC_CTL_GO |
+ MSGDMA_DESC_CTL_END_ON_LEN;
+}
+
+/**
+ * msgdma_desc_config_eod - Mark the descriptor as end descriptor
+ * @desc: Hw descriptor pointer
+ */
+static void msgdma_desc_config_eod(struct msgdma_extended_desc *desc)
+{
+ desc->control |= MSGDMA_DESC_CTL_TR_COMP_IRQ;
+}
+
+/**
+ * msgdma_tx_submit - Submit DMA transaction
+ * @tx: Async transaction descriptor pointer
+ *
+ * Return: cookie value
+ */
+static dma_cookie_t msgdma_tx_submit(struct dma_async_tx_descriptor *tx)
+{
+ struct msgdma_device *mdev = to_mdev(tx->chan);
+ struct msgdma_sw_desc *new;
+ dma_cookie_t cookie;
+
+ new = tx_to_desc(tx);
+ spin_lock_bh(&mdev->lock);
+ cookie = dma_cookie_assign(tx);
+
+ list_add_tail(&new->node, &mdev->pending_list);
+ spin_unlock_bh(&mdev->lock);
+
+ return cookie;
+}
+
+/**
+ * msgdma_prep_memcpy - prepare descriptors for memcpy transaction
+ * @dchan: DMA channel
+ * @dma_dst: Destination buffer address
+ * @dma_src: Source buffer address
+ * @len: Transfer length
+ * @flags: transfer ack flags
+ *
+ * Return: Async transaction descriptor on success and NULL on failure
+ */
+static struct dma_async_tx_descriptor *
+msgdma_prep_memcpy(struct dma_chan *dchan, dma_addr_t dma_dst,
+ dma_addr_t dma_src, size_t len, ulong flags)
+{
+ struct msgdma_device *mdev = to_mdev(dchan);
+ struct msgdma_sw_desc *new, *first = NULL;
+ struct msgdma_extended_desc *desc;
+ size_t copy;
+ u32 desc_cnt;
+
+ desc_cnt = DIV_ROUND_UP(len, MSGDMA_MAX_TRANS_LEN);
+
+ spin_lock_bh(&mdev->lock);
+ if (desc_cnt > mdev->desc_free_cnt) {
+ spin_unlock_bh(&mdev->lock);
+ dev_dbg(mdev->dev, "mdev %p descs are not available\n", mdev);
+ return NULL;
+ }
+ mdev->desc_free_cnt -= desc_cnt;
+ spin_unlock_bh(&mdev->lock);
+
+ do {
+ /* Allocate and populate the descriptor */
+ new = msgdma_get_descriptor(mdev);
+
+ copy = min_t(size_t, len, MSGDMA_MAX_TRANS_LEN);
+ desc = &new->hw_desc;
+ msgdma_desc_config(desc, dma_dst, dma_src, copy,
+ MSGDMA_DESC_STRIDE_RW);
+ len -= copy;
+ dma_src += copy;
+ dma_dst += copy;
+ if (!first)
+ first = new;
+ else
+ list_add_tail(&new->node, &first->tx_list);
+ } while (len);
+
+ msgdma_desc_config_eod(desc);
+ async_tx_ack(&first->async_tx);
+ first->async_tx.flags = flags;
+
+ return &first->async_tx;
+}
+
+/**
+ * msgdma_prep_sg - prepare descriptors for a memory sg transaction
+ * @dchan: DMA channel
+ * @dst_sg: Destination scatter list
+ * @dst_sg_len: Number of entries in destination scatter list
+ * @src_sg: Source scatter list
+ * @src_sg_len: Number of entries in source scatter list
+ * @flags: transfer ack flags
+ *
+ * Return: Async transaction descriptor on success and NULL on failure
+ */
+static struct dma_async_tx_descriptor *
+msgdma_prep_sg(struct dma_chan *dchan, struct scatterlist *dst_sg,
+ unsigned int dst_sg_len, struct scatterlist *src_sg,
+ unsigned int src_sg_len, unsigned long flags)
+{
+ struct msgdma_device *mdev = to_mdev(dchan);
+ struct msgdma_sw_desc *new, *first = NULL;
+ void *desc = NULL;
+ size_t len, dst_avail, src_avail;
+ dma_addr_t dma_dst, dma_src;
+ u32 desc_cnt = 0, i;
+ struct scatterlist *sg;
+
+ for_each_sg(src_sg, sg, src_sg_len, i)
+ desc_cnt += DIV_ROUND_UP(sg_dma_len(sg), MSGDMA_MAX_TRANS_LEN);
+
+ spin_lock_bh(&mdev->lock);
+ if (desc_cnt > mdev->desc_free_cnt) {
+ spin_unlock_bh(&mdev->lock);
+ dev_dbg(mdev->dev, "mdev %p descs are not available\n", mdev);
+ return NULL;
+ }
+ mdev->desc_free_cnt -= desc_cnt;
+ spin_unlock_bh(&mdev->lock);
+
+ dst_avail = sg_dma_len(dst_sg);
+ src_avail = sg_dma_len(src_sg);
+
+ /* Run until we are out of scatterlist entries */
+ while (true) {
+ /* Allocate and populate the descriptor */
+ new = msgdma_get_descriptor(mdev);
+
+ desc = &new->hw_desc;
+ len = min_t(size_t, src_avail, dst_avail);
+ len = min_t(size_t, len, MSGDMA_MAX_TRANS_LEN);
+ if (len == 0)
+ goto fetch;
+ dma_dst = sg_dma_address(dst_sg) + sg_dma_len(dst_sg) -
+ dst_avail;
+ dma_src = sg_dma_address(src_sg) + sg_dma_len(src_sg) -
+ src_avail;
+
+ msgdma_desc_config(desc, dma_dst, dma_src, len,
+ MSGDMA_DESC_STRIDE_RW);
+ dst_avail -= len;
+ src_avail -= len;
+
+ if (!first)
+ first = new;
+ else
+ list_add_tail(&new->node, &first->tx_list);
+fetch:
+ /* Fetch the next dst scatterlist entry */
+ if (dst_avail == 0) {
+ if (dst_sg_len == 0)
+ break;
+ dst_sg = sg_next(dst_sg);
+ if (dst_sg == NULL)
+ break;
+ dst_sg_len--;
+ dst_avail = sg_dma_len(dst_sg);
+ }
+ /* Fetch the next src scatterlist entry */
+ if (src_avail == 0) {
+ if (src_sg_len == 0)
+ break;
+ src_sg = sg_next(src_sg);
+ if (src_sg == NULL)
+ break;
+ src_sg_len--;
+ src_avail = sg_dma_len(src_sg);
+ }
+ }
+
+ msgdma_desc_config_eod(desc);
+ first->async_tx.flags = flags;
+
+ return &first->async_tx;
+}
+
+/**
+ * msgdma_prep_slave_sg - prepare descriptors for a slave sg transaction
+ *
+ * @dchan: DMA channel
+ * @sgl: Destination scatter list
+ * @sg_len: Number of entries in destination scatter list
+ * @dir: DMA transfer direction
+ * @flags: transfer ack flags
+ * @context: transfer context (unused)
+ */
+static struct dma_async_tx_descriptor *
+msgdma_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 msgdma_device *mdev = to_mdev(dchan);
+ struct dma_slave_config *cfg = &mdev->slave_cfg;
+ struct msgdma_sw_desc *new, *first = NULL;
+ void *desc = NULL;
+ size_t len, avail;
+ dma_addr_t dma_dst, dma_src;
+ u32 desc_cnt = 0, i;
+ struct scatterlist *sg;
+ u32 stride;
+
+ for_each_sg(sgl, sg, sg_len, i)
+ desc_cnt += DIV_ROUND_UP(sg_dma_len(sg), MSGDMA_MAX_TRANS_LEN);
+
+ spin_lock_bh(&mdev->lock);
+ if (desc_cnt > mdev->desc_free_cnt) {
+ spin_unlock_bh(&mdev->lock);
+ dev_dbg(mdev->dev, "mdev %p descs are not available\n", mdev);
+ return NULL;
+ }
+ mdev->desc_free_cnt -= desc_cnt;
+ spin_unlock_bh(&mdev->lock);
+
+ avail = sg_dma_len(sgl);
+
+ /* Run until we are out of scatterlist entries */
+ while (true) {
+ /* Allocate and populate the descriptor */
+ new = msgdma_get_descriptor(mdev);
+
+ desc = &new->hw_desc;
+ len = min_t(size_t, avail, MSGDMA_MAX_TRANS_LEN);
+
+ if (dir == DMA_MEM_TO_DEV) {
+ dma_src = sg_dma_address(sgl) + sg_dma_len(sgl) - avail;
+ dma_dst = cfg->dst_addr;
+ stride = MSGDMA_DESC_STRIDE_RD;
+ } else {
+ dma_src = cfg->src_addr;
+ dma_dst = sg_dma_address(sgl) + sg_dma_len(sgl) - avail;
+ stride = MSGDMA_DESC_STRIDE_WR;
+ }
+ msgdma_desc_config(desc, dma_dst, dma_src, len, stride);
+ avail -= len;
+
+ if (!first)
+ first = new;
+ else
+ list_add_tail(&new->node, &first->tx_list);
+
+ /* Fetch the next scatterlist entry */
+ if (avail == 0) {
+ if (sg_len == 0)
+ break;
+ sgl = sg_next(sgl);
+ if (sgl == NULL)
+ break;
+ sg_len--;
+ avail = sg_dma_len(sgl);
+ }
+ }
+
+ msgdma_desc_config_eod(desc);
+ first->async_tx.flags = flags;
+
+ return &first->async_tx;
+}
+
+static int msgdma_dma_config(struct dma_chan *dchan,
+ struct dma_slave_config *config)
+{
+ struct msgdma_device *mdev = to_mdev(dchan);
+
+ memcpy(&mdev->slave_cfg, config, sizeof(*config));
+
+ return 0;
+}
+
+static void msgdma_reset(struct msgdma_device *mdev)
+{
+ u32 val;
+ int ret;
+
+ /* Reset mSGDMA */
+ iowrite32(MSGDMA_CSR_STAT_MASK, &mdev->csr->status);
+ iowrite32(MSGDMA_CSR_CTL_RESET, &mdev->csr->control);
+
+ ret = readl_poll_timeout(&mdev->csr->status, val,
+ (val & MSGDMA_CSR_STAT_RESETTING) == 0,
+ 1, 10000);
+ if (ret)
+ dev_err(mdev->dev, "DMA channel did not reset\n");
+
+ /* Clear all status bits */
+ iowrite32(MSGDMA_CSR_STAT_MASK, &mdev->csr->status);
+
+ /* Enable the DMA controller including interrupts */
+ iowrite32(MSGDMA_CSR_CTL_STOP_ON_ERR | MSGDMA_CSR_CTL_STOP_ON_EARLY |
+ MSGDMA_CSR_CTL_GLOBAL_INTR, &mdev->csr->control);
+
+ mdev->idle = true;
+};
+
+static void msgdma_copy_one(struct msgdma_device *mdev,
+ struct msgdma_sw_desc *desc)
+{
+ struct msgdma_extended_desc *hw_desc = mdev->desc;
+
+ /*
+ * Check if the DESC FIFO it not full. If its full, we need to wait
+ * for at least one entry to become free again
+ */
+ while (ioread32(&mdev->csr->status) & MSGDMA_CSR_STAT_DESC_BUF_FULL)
+ mdelay(1);
+
+ /*
+ * The descriptor needs to get copied into the descriptor FIFO
+ * of the DMA controller. The descriptor will get flushed to the
+ * FIFO, once the last word (control word) is written. Since we
+ * are not 100% sure that memcpy() writes all word in the "correct"
+ * oder (address from low to high) on all architectures, we make
+ * sure this control word is written last by single coding it and
+ * adding some write-barriers here.
+ */
+ memcpy(hw_desc, &desc->hw_desc, sizeof(desc->hw_desc) - sizeof(u32));
+
+ /* Write control word last to flush this descriptor into the FIFO */
+ mdev->idle = false;
+ wmb();
+ iowrite32(desc->hw_desc.control, &hw_desc->control);
+ wmb();
+}
+
+/**
+ * msgdma_copy_desc_to_fifo - copy descriptor(s) into controller FIFO
+ * @mdev: Pointer to the Altera mSGDMA device structure
+ * @desc: Transaction descriptor pointer
+ */
+static void msgdma_copy_desc_to_fifo(struct msgdma_device *mdev,
+ struct msgdma_sw_desc *desc)
+{
+ struct msgdma_sw_desc *sdesc, *next;
+
+ msgdma_copy_one(mdev, desc);
+
+ list_for_each_entry_safe(sdesc, next, &desc->tx_list, node)
+ msgdma_copy_one(mdev, sdesc);
+}
+
+/**
+ * msgdma_start_transfer - Initiate the new transfer
+ * @mdev: Pointer to the Altera mSGDMA device structure
+ */
+static void msgdma_start_transfer(struct msgdma_device *mdev)
+{
+ struct msgdma_sw_desc *desc;
+
+ if (!mdev->idle)
+ return;
+
+ desc = list_first_entry_or_null(&mdev->pending_list,
+ struct msgdma_sw_desc, node);
+ if (!desc)
+ return;
+
+ list_splice_tail_init(&mdev->pending_list, &mdev->active_list);
+ msgdma_copy_desc_to_fifo(mdev, desc);
+}
+
+/**
+ * msgdma_issue_pending - Issue pending transactions
+ * @chan: DMA channel pointer
+ */
+static void msgdma_issue_pending(struct dma_chan *chan)
+{
+ struct msgdma_device *mdev = to_mdev(chan);
+
+ spin_lock_bh(&mdev->lock);
+ msgdma_start_transfer(mdev);
+ spin_unlock_bh(&mdev->lock);
+}
+
+/**
+ * msgdma_chan_desc_cleanup - Cleanup the completed descriptors
+ * @mdev: Pointer to the Altera mSGDMA device structure
+ */
+static void msgdma_chan_desc_cleanup(struct msgdma_device *mdev)
+{
+ struct msgdma_sw_desc *desc, *next;
+
+ list_for_each_entry_safe(desc, next, &mdev->done_list, node) {
+ dma_async_tx_callback callback;
+ void *callback_param;
+
+ list_del(&desc->node);
+
+ callback = desc->async_tx.callback;
+ callback_param = desc->async_tx.callback_param;
+ if (callback) {
+ spin_unlock(&mdev->lock);
+ callback(callback_param);
+ spin_lock(&mdev->lock);
+ }
+
+ /* Run any dependencies, then free the descriptor */
+ msgdma_free_descriptor(mdev, desc);
+ }
+}
+
+/**
+ * msgdma_complete_descriptor - Mark the active descriptor as complete
+ * @mdev: Pointer to the Altera mSGDMA device structure
+ */
+static void msgdma_complete_descriptor(struct msgdma_device *mdev)
+{
+ struct msgdma_sw_desc *desc;
+
+ desc = list_first_entry_or_null(&mdev->active_list,
+ struct msgdma_sw_desc, node);
+ if (!desc)
+ return;
+ list_del(&desc->node);
+ dma_cookie_complete(&desc->async_tx);
+ list_add_tail(&desc->node, &mdev->done_list);
+}
+
+/**
+ * msgdma_free_descriptors - Free channel descriptors
+ * @mdev: Pointer to the Altera mSGDMA device structure
+ */
+static void msgdma_free_descriptors(struct msgdma_device *mdev)
+{
+ msgdma_free_desc_list(mdev, &mdev->active_list);
+ msgdma_free_desc_list(mdev, &mdev->pending_list);
+ msgdma_free_desc_list(mdev, &mdev->done_list);
+}
+
+/**
+ * msgdma_free_chan_resources - Free channel resources
+ * @dchan: DMA channel pointer
+ */
+static void msgdma_free_chan_resources(struct dma_chan *dchan)
+{
+ struct msgdma_device *mdev = to_mdev(dchan);
+
+ spin_lock_bh(&mdev->lock);
+ msgdma_free_descriptors(mdev);
+ spin_unlock_bh(&mdev->lock);
+ kfree(mdev->sw_desq);
+}
+
+/**
+ * msgdma_alloc_chan_resources - Allocate channel resources
+ * @dchan: DMA channel
+ *
+ * Return: Number of descriptors on success and failure value on error
+ */
+static int msgdma_alloc_chan_resources(struct dma_chan *dchan)
+{
+ struct msgdma_device *mdev = to_mdev(dchan);
+ struct msgdma_sw_desc *desc;
+ int i;
+
+ mdev->sw_desq = kcalloc(MSGDMA_DESC_NUM, sizeof(*desc), GFP_NOWAIT);
+ if (!mdev->sw_desq)
+ return -ENOMEM;
+
+ mdev->idle = true;
+ mdev->desc_free_cnt = MSGDMA_DESC_NUM;
+
+ INIT_LIST_HEAD(&mdev->free_list);
+
+ for (i = 0; i < MSGDMA_DESC_NUM; i++) {
+ desc = mdev->sw_desq + i;
+ dma_async_tx_descriptor_init(&desc->async_tx, &mdev->dmachan);
+ desc->async_tx.tx_submit = msgdma_tx_submit;
+ list_add_tail(&desc->node, &mdev->free_list);
+ }
+
+ return MSGDMA_DESC_NUM;
+}
+
+/**
+ * msgdma_tasklet - Schedule completion tasklet
+ * @data: Pointer to the Altera sSGDMA channel structure
+ */
+static void msgdma_tasklet(unsigned long data)
+{
+ struct msgdma_device *mdev = (struct msgdma_device *)data;
+ u32 count;
+ u32 size;
+ u32 status;
+
+ spin_lock(&mdev->lock);
+
+ /* Read number of responses that are available */
+ count = ioread32(&mdev->csr->resp_fill_level);
+ dev_dbg(mdev->dev, "%s (%d): response count=%d\n",
+ __func__, __LINE__, count);
+
+ while (count--) {
+ /*
+ * Read both longwords to purge this response from the FIFO
+ * On Avalon-MM implementations, size and status do not
+ * have any real values, like transferred bytes or error
+ * bits. So we need to just drop these values.
+ */
+ size = ioread32(&mdev->resp->bytes_transferred);
+ status = ioread32(&mdev->resp->status);
+
+ msgdma_complete_descriptor(mdev);
+ msgdma_chan_desc_cleanup(mdev);
+ }
+
+ spin_unlock(&mdev->lock);
+}
+
+/**
+ * msgdma_irq_handler - Altera mSGDMA Interrupt handler
+ * @irq: IRQ number
+ * @data: Pointer to the Altera mSGDMA device structure
+ *
+ * Return: IRQ_HANDLED/IRQ_NONE
+ */
+static irqreturn_t msgdma_irq_handler(int irq, void *data)
+{
+ struct msgdma_device *mdev = data;
+ u32 status;
+
+ status = ioread32(&mdev->csr->status);
+ if ((status & MSGDMA_CSR_STAT_BUSY) == 0) {
+ /* Start next transfer if the DMA controller is idle */
+ spin_lock(&mdev->lock);
+ mdev->idle = true;
+ msgdma_start_transfer(mdev);
+ spin_unlock(&mdev->lock);
+ }
+
+ tasklet_schedule(&mdev->irq_tasklet);
+
+ /* Clear interrupt in mSGDMA controller */
+ iowrite32(MSGDMA_CSR_STAT_IRQ, &mdev->csr->status);
+
+ return IRQ_HANDLED;
+}
+
+/**
+ * msgdma_chan_remove - Channel remove function
+ * @mdev: Pointer to the Altera mSGDMA device structure
+ */
+static void msgdma_dev_remove(struct msgdma_device *mdev)
+{
+ if (!mdev)
+ return;
+
+ devm_free_irq(mdev->dev, mdev->irq, mdev);
+ tasklet_kill(&mdev->irq_tasklet);
+ list_del(&mdev->dmachan.device_node);
+}
+
+static int request_and_map(struct platform_device *pdev, const char *name,
+ struct resource **res, void __iomem **ptr)
+{
+ struct resource *region;
+ struct device *device = &pdev->dev;
+
+ *res = platform_get_resource_byname(pdev, IORESOURCE_MEM, name);
+ if (*res == NULL) {
+ dev_err(device, "resource %s not defined\n", name);
+ return -ENODEV;
+ }
+
+ region = devm_request_mem_region(device, (*res)->start,
+ resource_size(*res), dev_name(device));
+ if (region == NULL) {
+ dev_err(device, "unable to request %s\n", name);
+ return -EBUSY;
+ }
+
+ *ptr = devm_ioremap_nocache(device, region->start,
+ resource_size(region));
+ if (*ptr == NULL) {
+ dev_err(device, "ioremap_nocache of %s failed!", name);
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+/**
+ * msgdma_probe - Driver probe function
+ * @pdev: Pointer to the platform_device structure
+ *
+ * Return: '0' on success and failure value on error
+ */
+static int msgdma_probe(struct platform_device *pdev)
+{
+ struct msgdma_device *mdev;
+ struct dma_device *dma_dev;
+ struct resource *dma_res;
+ int ret;
+
+ mdev = devm_kzalloc(&pdev->dev, sizeof(*mdev), GFP_NOWAIT);
+ if (!mdev)
+ return -ENOMEM;
+
+ mdev->dev = &pdev->dev;
+
+ /* Map CSR space */
+ ret = request_and_map(pdev, "csr", &dma_res, (void **)&mdev->csr);
+ if (ret)
+ return ret;
+
+ /* Map (extended) descriptor space */
+ ret = request_and_map(pdev, "desc", &dma_res, (void **)&mdev->desc);
+ if (ret)
+ return ret;
+
+ /* Map response space */
+ ret = request_and_map(pdev, "resp", &dma_res, (void **)&mdev->resp);
+ if (ret)
+ return ret;
+
+ platform_set_drvdata(pdev, mdev);
+
+ /* Get interrupt nr from platform data */
+ mdev->irq = platform_get_irq(pdev, 0);
+ if (mdev->irq < 0)
+ return -ENXIO;
+
+ ret = devm_request_irq(&pdev->dev, mdev->irq, msgdma_irq_handler,
+ 0, dev_name(&pdev->dev), mdev);
+ if (ret)
+ return ret;
+
+ tasklet_init(&mdev->irq_tasklet, msgdma_tasklet, (unsigned long)mdev);
+
+ dma_cookie_init(&mdev->dmachan);
+
+ spin_lock_init(&mdev->lock);
+
+ INIT_LIST_HEAD(&mdev->active_list);
+ INIT_LIST_HEAD(&mdev->pending_list);
+ INIT_LIST_HEAD(&mdev->done_list);
+ INIT_LIST_HEAD(&mdev->free_list);
+
+ dma_dev = &mdev->dmadev;
+
+ /* Set DMA capabilities */
+ dma_cap_zero(dma_dev->cap_mask);
+ dma_cap_set(DMA_MEMCPY, dma_dev->cap_mask);
+ dma_cap_set(DMA_SG, dma_dev->cap_mask);
+ dma_cap_set(DMA_SLAVE, dma_dev->cap_mask);
+
+ dma_dev->src_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
+ dma_dev->dst_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
+ dma_dev->directions = BIT(DMA_MEM_TO_DEV) | BIT(DMA_DEV_TO_MEM) |
+ BIT(DMA_MEM_TO_MEM);
+ dma_dev->residue_granularity = DMA_RESIDUE_GRANULARITY_DESCRIPTOR;
+
+ /* Init DMA link list */
+ INIT_LIST_HEAD(&dma_dev->channels);
+
+ /* Set base routines */
+ dma_dev->device_tx_status = dma_cookie_status;
+ dma_dev->device_issue_pending = msgdma_issue_pending;
+ dma_dev->dev = &pdev->dev;
+
+ dma_dev->copy_align = DMAENGINE_ALIGN_4_BYTES;
+ dma_dev->device_prep_dma_memcpy = msgdma_prep_memcpy;
+ dma_dev->device_prep_dma_sg = msgdma_prep_sg;
+ dma_dev->device_prep_slave_sg = msgdma_prep_slave_sg;
+ dma_dev->device_config = msgdma_dma_config;
+
+ dma_dev->device_alloc_chan_resources = msgdma_alloc_chan_resources;
+ dma_dev->device_free_chan_resources = msgdma_free_chan_resources;
+
+ mdev->dmachan.device = dma_dev;
+ list_add_tail(&mdev->dmachan.device_node, &dma_dev->channels);
+
+ /* Set DMA mask to 64 bits */
+ ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));
+ if (ret) {
+ dev_warn(&pdev->dev, "unable to set coherent mask to 64");
+ ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
+ if (ret)
+ goto fail;
+ }
+
+ msgdma_reset(mdev);
+
+ ret = dma_async_device_register(dma_dev);
+ if (ret)
+ goto fail;
+
+ dev_notice(&pdev->dev, "Altera mSGDMA driver probe success\n");
+
+ return 0;
+
+fail:
+ msgdma_dev_remove(mdev);
+
+ return ret;
+}
+
+/**
+ * msgdma_dma_remove - Driver remove function
+ * @pdev: Pointer to the platform_device structure
+ *
+ * Return: Always '0'
+ */
+static int msgdma_remove(struct platform_device *pdev)
+{
+ struct msgdma_device *mdev = platform_get_drvdata(pdev);
+
+ dma_async_device_unregister(&mdev->dmadev);
+ msgdma_dev_remove(mdev);
+
+ dev_notice(&pdev->dev, "Altera mSGDMA driver removed\n");
+
+ return 0;
+}
+
+static struct platform_driver msgdma_driver = {
+ .driver = {
+ .name = "altera-msgdma",
+ },
+ .probe = msgdma_probe,
+ .remove = msgdma_remove,
+};
+
+module_platform_driver(msgdma_driver);
+
+MODULE_ALIAS("platform:altera-msgdma");
+MODULE_DESCRIPTION("Altera mSGDMA driver");
+MODULE_AUTHOR("Stefan Roese <sr@xxxxxxx>");
+MODULE_LICENSE("GPL");
--
2.13.2
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