[PATCH v1 4/5] dmaengine: Add driver for NVIDIA Tegra AHB DMA controller
From: Dmitry Osipenko
Date: Mon Sep 25 2017 - 19:25:17 EST
AHB DMA controller presents on Tegra20/30 SoC's, it supports transfers
memory <-> AHB bus peripherals as well as mem-to-mem transfers. Driver
doesn't yet implement transfers larger than 64K and scatter-gather
transfers that have NENT > 1, HW doesn't have native support for these
cases.
Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>
---
drivers/dma/Kconfig | 9 +
drivers/dma/Makefile | 1 +
drivers/dma/tegra20-ahb-dma.c | 679 ++++++++++++++++++++++++++++++++++++++++++
3 files changed, 689 insertions(+)
create mode 100644 drivers/dma/tegra20-ahb-dma.c
diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
index fadc4d8783bd..937c110a715b 100644
--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -503,6 +503,15 @@ config TXX9_DMAC
Support the TXx9 SoC internal DMA controller. This can be
integrated in chips such as the Toshiba TX4927/38/39.
+config TEGRA20_AHB_DMA
+ tristate "NVIDIA Tegra20 AHB DMA support"
+ depends on ARCH_TEGRA
+ select DMA_ENGINE
+ help
+ Enable support for the NVIDIA Tegra20 AHB DMA controller driver.
+ This DMA controller transfers data from memory to AHB peripherals
+ or vice versa, it supports memory to memory data transfer as well.
+
config TEGRA20_APB_DMA
bool "NVIDIA Tegra20 APB DMA support"
depends on ARCH_TEGRA
diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
index f08f8de1b567..82d5d36b0379 100644
--- a/drivers/dma/Makefile
+++ b/drivers/dma/Makefile
@@ -61,6 +61,7 @@ obj-$(CONFIG_STE_DMA40) += ste_dma40.o ste_dma40_ll.o
obj-$(CONFIG_STM32_DMA) += stm32-dma.o
obj-$(CONFIG_S3C24XX_DMAC) += s3c24xx-dma.o
obj-$(CONFIG_TXX9_DMAC) += txx9dmac.o
+obj-$(CONFIG_TEGRA20_AHB_DMA) += tegra20-ahb-dma.o
obj-$(CONFIG_TEGRA20_APB_DMA) += tegra20-apb-dma.o
obj-$(CONFIG_TEGRA210_ADMA) += tegra210-adma.o
obj-$(CONFIG_TIMB_DMA) += timb_dma.o
diff --git a/drivers/dma/tegra20-ahb-dma.c b/drivers/dma/tegra20-ahb-dma.c
new file mode 100644
index 000000000000..8316d64e35e1
--- /dev/null
+++ b/drivers/dma/tegra20-ahb-dma.c
@@ -0,0 +1,679 @@
+/*
+ * Copyright 2017 Dmitry Osipenko <digetx@xxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/of_dma.h>
+#include <linux/platform_device.h>
+#include <linux/reset.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+
+#include "dmaengine.h"
+
+#define TEGRA_AHBDMA_CMD 0x0
+#define TEGRA_AHBDMA_CMD_ENABLE BIT(31)
+
+#define TEGRA_AHBDMA_IRQ_ENB_MASK 0x20
+#define TEGRA_AHBDMA_IRQ_ENB_CH(ch) BIT(ch)
+
+#define TEGRA_AHBDMA_CHANNEL_BASE(ch) (0x1000 + (ch) * 0x20)
+
+#define TEGRA_AHBDMA_CHANNEL_CSR 0x0
+#define TEGRA_AHBDMA_CHANNEL_ADDR_WRAP BIT(18)
+#define TEGRA_AHBDMA_CHANNEL_FLOW BIT(24)
+#define TEGRA_AHBDMA_CHANNEL_ONCE BIT(26)
+#define TEGRA_AHBDMA_CHANNEL_DIR_TO_XMB BIT(27)
+#define TEGRA_AHBDMA_CHANNEL_IE_EOC BIT(30)
+#define TEGRA_AHBDMA_CHANNEL_ENABLE BIT(31)
+#define TEGRA_AHBDMA_CHANNEL_REQ_SEL_SHIFT 16
+#define TEGRA_AHBDMA_CHANNEL_WCOUNT_MASK 0xFFFC
+
+#define TEGRA_AHBDMA_CHANNEL_STA 0x4
+#define TEGRA_AHBDMA_CHANNEL_IS_EOC BIT(30)
+
+#define TEGRA_AHBDMA_CHANNEL_AHB_PTR 0x10
+
+#define TEGRA_AHBDMA_CHANNEL_AHB_SEQ 0x14
+#define TEGRA_AHBDMA_CHANNEL_INTR_ENB BIT(31)
+#define TEGRA_AHBDMA_CHANNEL_AHB_BURST_SHIFT 24
+#define TEGRA_AHBDMA_CHANNEL_AHB_BURST_1 2
+#define TEGRA_AHBDMA_CHANNEL_AHB_BURST_4 3
+#define TEGRA_AHBDMA_CHANNEL_AHB_BURST_8 4
+
+#define TEGRA_AHBDMA_CHANNEL_XMB_PTR 0x18
+
+#define TEGRA_AHBDMA_BUS_WIDTH BIT(DMA_SLAVE_BUSWIDTH_4_BYTES)
+
+#define TEGRA_AHBDMA_DIRECTIONS BIT(DMA_DEV_TO_MEM) | \
+ BIT(DMA_MEM_TO_DEV)
+
+struct tegra_ahbdma_tx_desc {
+ struct dma_async_tx_descriptor desc;
+ struct tasklet_struct tasklet;
+ struct list_head node;
+ enum dma_transfer_direction dir;
+ dma_addr_t mem_paddr;
+ unsigned long flags;
+ size_t size;
+ bool in_fly;
+ bool cyclic;
+};
+
+struct tegra_ahbdma_chan {
+ struct dma_chan dma_chan;
+ struct list_head active_list;
+ struct list_head pending_list;
+ struct completion idling;
+ void __iomem *regs;
+ spinlock_t lock;
+ unsigned int id;
+};
+
+struct tegra_ahbdma {
+ struct tegra_ahbdma_chan channels[4];
+ struct dma_device dma_dev;
+ struct reset_control *rst;
+ struct clk *clk;
+ void __iomem *regs;
+};
+
+static inline struct tegra_ahbdma *to_ahbdma(struct dma_device *dev)
+{
+ return container_of(dev, struct tegra_ahbdma, dma_dev);
+}
+
+static inline struct tegra_ahbdma_chan *to_ahbdma_chan(struct dma_chan *chan)
+{
+ return container_of(chan, struct tegra_ahbdma_chan, dma_chan);
+}
+
+static inline struct tegra_ahbdma_tx_desc *to_ahbdma_tx_desc(
+ struct dma_async_tx_descriptor *tx)
+{
+ return container_of(tx, struct tegra_ahbdma_tx_desc, desc);
+}
+
+static void tegra_ahbdma_submit_tx(struct tegra_ahbdma_chan *chan,
+ struct tegra_ahbdma_tx_desc *tx)
+{
+ u32 csr;
+
+ writel_relaxed(tx->mem_paddr,
+ chan->regs + TEGRA_AHBDMA_CHANNEL_XMB_PTR);
+
+ csr = readl_relaxed(chan->regs + TEGRA_AHBDMA_CHANNEL_CSR);
+
+ csr &= ~TEGRA_AHBDMA_CHANNEL_WCOUNT_MASK;
+ csr &= ~TEGRA_AHBDMA_CHANNEL_DIR_TO_XMB;
+ csr |= TEGRA_AHBDMA_CHANNEL_ENABLE;
+ csr |= TEGRA_AHBDMA_CHANNEL_IE_EOC;
+ csr |= tx->size - sizeof(u32);
+
+ if (tx->dir == DMA_DEV_TO_MEM)
+ csr |= TEGRA_AHBDMA_CHANNEL_DIR_TO_XMB;
+
+ if (!tx->cyclic)
+ csr |= TEGRA_AHBDMA_CHANNEL_ONCE;
+
+ writel_relaxed(csr, chan->regs + TEGRA_AHBDMA_CHANNEL_CSR);
+
+ tx->in_fly = true;
+}
+
+static void tegra_ahbdma_tasklet(unsigned long data)
+{
+ struct tegra_ahbdma_tx_desc *tx = (struct tegra_ahbdma_tx_desc *)data;
+ struct dma_async_tx_descriptor *desc = &tx->desc;
+
+ dmaengine_desc_get_callback_invoke(desc, NULL);
+
+ if (!tx->cyclic && !dmaengine_desc_test_reuse(desc))
+ kfree(tx);
+}
+
+static bool tegra_ahbdma_tx_completed(struct tegra_ahbdma_chan *chan,
+ struct tegra_ahbdma_tx_desc *tx)
+{
+ struct dma_async_tx_descriptor *desc = &tx->desc;
+ bool reuse = dmaengine_desc_test_reuse(desc);
+ bool interrupt = tx->flags & DMA_PREP_INTERRUPT;
+ bool completed = !tx->cyclic;
+
+ if (completed)
+ dma_cookie_complete(desc);
+
+ if (interrupt)
+ tasklet_schedule(&tx->tasklet);
+
+ if (completed) {
+ list_del(&tx->node);
+
+ if (reuse)
+ tx->in_fly = false;
+
+ if (!interrupt && !reuse)
+ kfree(tx);
+ }
+
+ return completed;
+}
+
+static bool tegra_ahbdma_next_tx_issued(struct tegra_ahbdma_chan *chan)
+{
+ struct tegra_ahbdma_tx_desc *tx;
+
+ tx = list_first_entry_or_null(&chan->active_list,
+ struct tegra_ahbdma_tx_desc,
+ node);
+ if (tx)
+ tegra_ahbdma_submit_tx(chan, tx);
+
+ return !!tx;
+}
+
+static void tegra_ahbdma_handle_channel(struct tegra_ahbdma_chan *chan)
+{
+ struct tegra_ahbdma_tx_desc *tx;
+ unsigned long flags;
+ u32 status;
+
+ status = readl_relaxed(chan->regs + TEGRA_AHBDMA_CHANNEL_STA);
+ if (!(status & TEGRA_AHBDMA_CHANNEL_IS_EOC))
+ return;
+
+ writel_relaxed(TEGRA_AHBDMA_CHANNEL_IS_EOC,
+ chan->regs + TEGRA_AHBDMA_CHANNEL_STA);
+
+ spin_lock_irqsave(&chan->lock, flags);
+
+ if (!completion_done(&chan->idling)) {
+ tx = list_first_entry(&chan->active_list,
+ struct tegra_ahbdma_tx_desc,
+ node);
+
+ if (tegra_ahbdma_tx_completed(chan, tx) &&
+ !tegra_ahbdma_next_tx_issued(chan))
+ complete_all(&chan->idling);
+ }
+
+ spin_unlock_irqrestore(&chan->lock, flags);
+}
+
+static irqreturn_t tegra_ahbdma_isr(int irq, void *dev_id)
+{
+ struct tegra_ahbdma *tdma = dev_id;
+ unsigned int i;
+
+ for (i = 0; i < ARRAY_SIZE(tdma->channels); i++)
+ tegra_ahbdma_handle_channel(&tdma->channels[i]);
+
+ return IRQ_HANDLED;
+}
+
+static dma_cookie_t tegra_ahbdma_tx_submit(struct dma_async_tx_descriptor *desc)
+{
+ struct tegra_ahbdma_tx_desc *tx = to_ahbdma_tx_desc(desc);
+ struct tegra_ahbdma_chan *chan = to_ahbdma_chan(desc->chan);
+ dma_cookie_t cookie;
+
+ cookie = dma_cookie_assign(desc);
+
+ spin_lock_irq(&chan->lock);
+ list_add_tail(&tx->node, &chan->pending_list);
+ spin_unlock_irq(&chan->lock);
+
+ return cookie;
+}
+
+static int tegra_ahbdma_tx_desc_free(struct dma_async_tx_descriptor *desc)
+{
+ kfree(to_ahbdma_tx_desc(desc));
+
+ return 0;
+}
+
+static struct dma_async_tx_descriptor *tegra_ahbdma_prep_slave_sg(
+ struct dma_chan *chan,
+ struct scatterlist *sgl,
+ unsigned int sg_len,
+ enum dma_transfer_direction dir,
+ unsigned long flags,
+ void *context)
+{
+ struct tegra_ahbdma_tx_desc *tx;
+
+ /* unimplemented */
+ if (sg_len != 1 || sg_dma_len(sgl) > SZ_64K)
+ return NULL;
+
+ tx = kzalloc(sizeof(*tx), GFP_KERNEL);
+ if (!tx)
+ return NULL;
+
+ dma_async_tx_descriptor_init(&tx->desc, chan);
+
+ tx->desc.tx_submit = tegra_ahbdma_tx_submit;
+ tx->desc.desc_free = tegra_ahbdma_tx_desc_free;
+ tx->mem_paddr = sg_dma_address(sgl);
+ tx->size = sg_dma_len(sgl);
+ tx->flags = flags;
+ tx->dir = dir;
+
+ tasklet_init(&tx->tasklet, tegra_ahbdma_tasklet, (unsigned long)tx);
+
+ return &tx->desc;
+}
+
+static struct dma_async_tx_descriptor *tegra_ahbdma_prep_dma_cyclic(
+ struct dma_chan *chan,
+ dma_addr_t buf_addr,
+ size_t buf_len,
+ size_t period_len,
+ enum dma_transfer_direction dir,
+ unsigned long flags)
+{
+ struct tegra_ahbdma_tx_desc *tx;
+
+ /* unimplemented */
+ if (buf_len != period_len || buf_len > SZ_64K)
+ return NULL;
+
+ tx = kzalloc(sizeof(*tx), GFP_KERNEL);
+ if (!tx)
+ return NULL;
+
+ dma_async_tx_descriptor_init(&tx->desc, chan);
+
+ tx->desc.tx_submit = tegra_ahbdma_tx_submit;
+ tx->mem_paddr = buf_addr;
+ tx->size = buf_len;
+ tx->flags = flags;
+ tx->cyclic = true;
+ tx->dir = dir;
+
+ tasklet_init(&tx->tasklet, tegra_ahbdma_tasklet, (unsigned long)tx);
+
+ return &tx->desc;
+}
+
+static void tegra_ahbdma_issue_pending(struct dma_chan *chan)
+{
+ struct tegra_ahbdma_chan *ahbdma_chan = to_ahbdma_chan(chan);
+ struct tegra_ahbdma_tx_desc *tx;
+ struct list_head *entry, *tmp;
+ unsigned long flags;
+
+ spin_lock_irqsave(&ahbdma_chan->lock, flags);
+
+ list_for_each_safe(entry, tmp, &ahbdma_chan->pending_list)
+ list_move_tail(entry, &ahbdma_chan->active_list);
+
+ if (completion_done(&ahbdma_chan->idling)) {
+ tx = list_first_entry_or_null(&ahbdma_chan->active_list,
+ struct tegra_ahbdma_tx_desc,
+ node);
+ if (tx) {
+ tegra_ahbdma_submit_tx(ahbdma_chan, tx);
+ reinit_completion(&ahbdma_chan->idling);
+ }
+ }
+
+ spin_unlock_irqrestore(&ahbdma_chan->lock, flags);
+}
+
+static enum dma_status tegra_ahbdma_tx_status(struct dma_chan *chan,
+ dma_cookie_t cookie,
+ struct dma_tx_state *state)
+{
+ struct tegra_ahbdma_chan *ahbdma_chan = to_ahbdma_chan(chan);
+ struct tegra_ahbdma_tx_desc *tx;
+ enum dma_status cookie_status;
+ unsigned long flags;
+ size_t residual;
+ u32 status;
+
+ spin_lock_irqsave(&ahbdma_chan->lock, flags);
+
+ cookie_status = dma_cookie_status(chan, cookie, state);
+ if (cookie_status != DMA_COMPLETE) {
+ list_for_each_entry(tx, &ahbdma_chan->active_list, node) {
+ if (tx->desc.cookie == cookie)
+ goto found;
+ }
+ }
+
+ goto unlock;
+
+found:
+ if (tx->in_fly) {
+ status = readl_relaxed(
+ ahbdma_chan->regs + TEGRA_AHBDMA_CHANNEL_STA);
+ status &= TEGRA_AHBDMA_CHANNEL_WCOUNT_MASK;
+
+ residual = status;
+ } else
+ residual = tx->size;
+
+ dma_set_residue(state, residual);
+
+unlock:
+ spin_unlock_irqrestore(&ahbdma_chan->lock, flags);
+
+ return cookie_status;
+}
+
+static int tegra_ahbdma_terminate_all(struct dma_chan *chan)
+{
+ struct tegra_ahbdma_chan *ahbdma_chan = to_ahbdma_chan(chan);
+ struct tegra_ahbdma_tx_desc *tx;
+ struct list_head *entry, *tmp;
+ u32 csr;
+
+ spin_lock_irq(&ahbdma_chan->lock);
+
+ csr = readl_relaxed(ahbdma_chan->regs + TEGRA_AHBDMA_CHANNEL_CSR);
+ csr &= ~TEGRA_AHBDMA_CHANNEL_ENABLE;
+
+ writel_relaxed(csr, ahbdma_chan->regs + TEGRA_AHBDMA_CHANNEL_CSR);
+
+ list_for_each_safe(entry, tmp, &ahbdma_chan->active_list) {
+ tx = list_entry(entry, struct tegra_ahbdma_tx_desc, node);
+ list_del(entry);
+ kfree(tx);
+ }
+
+ list_for_each_safe(entry, tmp, &ahbdma_chan->pending_list) {
+ tx = list_entry(entry, struct tegra_ahbdma_tx_desc, node);
+ list_del(entry);
+ kfree(tx);
+ }
+
+ complete_all(&ahbdma_chan->idling);
+
+ spin_unlock_irq(&ahbdma_chan->lock);
+
+ return 0;
+}
+
+static int tegra_ahbdma_config(struct dma_chan *chan,
+ struct dma_slave_config *sconfig)
+{
+ struct tegra_ahbdma_chan *ahbdma_chan = to_ahbdma_chan(chan);
+ enum dma_transfer_direction dir = sconfig->direction;
+ u32 burst, ahb_seq, ahb_addr;
+
+ if (sconfig->src_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES ||
+ sconfig->dst_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES)
+ return -EINVAL;
+
+ if (dir == DMA_DEV_TO_MEM) {
+ burst = sconfig->src_maxburst;
+ ahb_addr = sconfig->src_addr;
+ } else {
+ burst = sconfig->dst_maxburst;
+ ahb_addr = sconfig->dst_addr;
+ }
+
+ switch (burst) {
+ case 1: burst = TEGRA_AHBDMA_CHANNEL_AHB_BURST_1; break;
+ case 4: burst = TEGRA_AHBDMA_CHANNEL_AHB_BURST_4; break;
+ case 8: burst = TEGRA_AHBDMA_CHANNEL_AHB_BURST_8; break;
+ default:
+ return -EINVAL;
+ }
+
+ ahb_seq = burst << TEGRA_AHBDMA_CHANNEL_AHB_BURST_SHIFT;
+ ahb_seq |= TEGRA_AHBDMA_CHANNEL_ADDR_WRAP;
+ ahb_seq |= TEGRA_AHBDMA_CHANNEL_INTR_ENB;
+
+ writel_relaxed(ahb_seq,
+ ahbdma_chan->regs + TEGRA_AHBDMA_CHANNEL_AHB_SEQ);
+
+ writel_relaxed(ahb_addr,
+ ahbdma_chan->regs + TEGRA_AHBDMA_CHANNEL_AHB_PTR);
+
+ return 0;
+}
+
+static void tegra_ahbdma_synchronize(struct dma_chan *chan)
+{
+ wait_for_completion(&to_ahbdma_chan(chan)->idling);
+}
+
+static void tegra_ahbdma_free_chan_resources(struct dma_chan *chan)
+{
+ struct tegra_ahbdma_chan *ahbdma_chan = to_ahbdma_chan(chan);
+ struct tegra_ahbdma_tx_desc *tx;
+ struct list_head *entry, *tmp;
+
+ list_for_each_safe(entry, tmp, &ahbdma_chan->pending_list) {
+ tx = list_entry(entry, struct tegra_ahbdma_tx_desc, node);
+ list_del(entry);
+ kfree(tx);
+ }
+}
+
+static void tegra_ahbdma_init_channel(struct tegra_ahbdma *tdma,
+ unsigned int chan_id)
+{
+ struct tegra_ahbdma_chan *ahbdma_chan = &tdma->channels[chan_id];
+ struct dma_chan *dma_chan = &ahbdma_chan->dma_chan;
+ struct dma_device *dma_dev = &tdma->dma_dev;
+
+ INIT_LIST_HEAD(&ahbdma_chan->active_list);
+ INIT_LIST_HEAD(&ahbdma_chan->pending_list);
+ init_completion(&ahbdma_chan->idling);
+ spin_lock_init(&ahbdma_chan->lock);
+ complete(&ahbdma_chan->idling);
+
+ ahbdma_chan->regs = tdma->regs + TEGRA_AHBDMA_CHANNEL_BASE(chan_id);
+ ahbdma_chan->id = chan_id;
+
+ dma_cookie_init(dma_chan);
+ dma_chan->device = dma_dev;
+
+ list_add_tail(&dma_chan->device_node, &dma_dev->channels);
+}
+
+static struct dma_chan *tegra_ahbdma_of_xlate(struct of_phandle_args *dma_spec,
+ struct of_dma *ofdma)
+{
+ struct tegra_ahbdma *tdma = ofdma->of_dma_data;
+ struct dma_chan *chan;
+ u32 csr;
+
+ chan = dma_get_any_slave_channel(&tdma->dma_dev);
+ if (!chan)
+ return NULL;
+
+ /* enable channels flow control */
+ if (dma_spec->args_count == 1) {
+ csr = TEGRA_AHBDMA_CHANNEL_FLOW;
+ csr |= dma_spec->args[0] << TEGRA_AHBDMA_CHANNEL_REQ_SEL_SHIFT;
+
+ writel_relaxed(csr,
+ to_ahbdma_chan(chan)->regs + TEGRA_AHBDMA_CHANNEL_CSR);
+ }
+
+ return chan;
+}
+
+static int tegra_ahbdma_init_hw(struct tegra_ahbdma *tdma, struct device *dev)
+{
+ int err;
+
+ err = reset_control_assert(tdma->rst);
+ if (err) {
+ dev_err(dev, "Failed to assert reset: %d\n", err);
+ return err;
+ }
+
+ err = clk_prepare_enable(tdma->clk);
+ if (err) {
+ dev_err(dev, "Failed to enable clock: %d\n", err);
+ return err;
+ }
+
+ usleep_range(1000, 2000);
+
+ err = reset_control_deassert(tdma->rst);
+ if (err) {
+ dev_err(dev, "Failed to deassert reset: %d\n", err);
+ return err;
+ }
+
+ writel_relaxed(TEGRA_AHBDMA_CMD_ENABLE, tdma->regs + TEGRA_AHBDMA_CMD);
+
+ writel_relaxed(TEGRA_AHBDMA_IRQ_ENB_CH(0) |
+ TEGRA_AHBDMA_IRQ_ENB_CH(1) |
+ TEGRA_AHBDMA_IRQ_ENB_CH(2) |
+ TEGRA_AHBDMA_IRQ_ENB_CH(3),
+ tdma->regs + TEGRA_AHBDMA_IRQ_ENB_MASK);
+
+ return 0;
+}
+
+static int tegra_ahbdma_probe(struct platform_device *pdev)
+{
+ struct dma_device *dma_dev;
+ struct tegra_ahbdma *tdma;
+ struct resource *res_regs;
+ unsigned int i;
+ int irq;
+ int err;
+
+ tdma = devm_kzalloc(&pdev->dev, sizeof(*tdma), GFP_KERNEL);
+ if (!tdma)
+ return -ENOMEM;
+
+ irq = platform_get_irq(pdev, 0);
+ if (irq < 0) {
+ dev_err(&pdev->dev, "Failed to get IRQ\n");
+ return irq;
+ }
+
+ err = devm_request_irq(&pdev->dev, irq, tegra_ahbdma_isr, 0,
+ dev_name(&pdev->dev), tdma);
+ if (err) {
+ dev_err(&pdev->dev, "Failed to request IRQ\n");
+ return -ENODEV;
+ }
+
+ res_regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res_regs)
+ return -ENODEV;
+
+ tdma->regs = devm_ioremap_resource(&pdev->dev, res_regs);
+ if (IS_ERR(tdma->regs))
+ return PTR_ERR(tdma->regs);
+
+ tdma->clk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(tdma->clk)) {
+ dev_err(&pdev->dev, "Failed to get AHB-DMA clock\n");
+ return PTR_ERR(tdma->clk);
+ }
+
+ tdma->rst = devm_reset_control_get(&pdev->dev, NULL);
+ if (IS_ERR(tdma->rst)) {
+ dev_err(&pdev->dev, "Failed to get AHB-DMA reset\n");
+ return PTR_ERR(tdma->rst);
+ }
+
+ err = tegra_ahbdma_init_hw(tdma, &pdev->dev);
+ if (err)
+ return err;
+
+ dma_dev = &tdma->dma_dev;
+
+ INIT_LIST_HEAD(&dma_dev->channels);
+
+ for (i = 0; i < ARRAY_SIZE(tdma->channels); i++)
+ tegra_ahbdma_init_channel(tdma, i);
+
+ dma_cap_set(DMA_PRIVATE, dma_dev->cap_mask);
+ dma_cap_set(DMA_CYCLIC, dma_dev->cap_mask);
+ dma_cap_set(DMA_SLAVE, dma_dev->cap_mask);
+
+ dma_dev->max_burst = 8;
+ dma_dev->directions = TEGRA_AHBDMA_DIRECTIONS;
+ dma_dev->src_addr_widths = TEGRA_AHBDMA_BUS_WIDTH;
+ dma_dev->dst_addr_widths = TEGRA_AHBDMA_BUS_WIDTH;
+ dma_dev->descriptor_reuse = true;
+ dma_dev->residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
+ dma_dev->device_free_chan_resources = tegra_ahbdma_free_chan_resources;
+ dma_dev->device_prep_slave_sg = tegra_ahbdma_prep_slave_sg;
+ dma_dev->device_prep_dma_cyclic = tegra_ahbdma_prep_dma_cyclic;
+ dma_dev->device_terminate_all = tegra_ahbdma_terminate_all;
+ dma_dev->device_issue_pending = tegra_ahbdma_issue_pending;
+ dma_dev->device_tx_status = tegra_ahbdma_tx_status;
+ dma_dev->device_config = tegra_ahbdma_config;
+ dma_dev->device_synchronize = tegra_ahbdma_synchronize;
+ dma_dev->dev = &pdev->dev;
+
+ err = dma_async_device_register(dma_dev);
+ if (err) {
+ dev_err(&pdev->dev, "Device registration failed %d\n", err);
+ return err;
+ }
+
+ err = of_dma_controller_register(pdev->dev.of_node,
+ tegra_ahbdma_of_xlate, tdma);
+ if (err) {
+ dev_err(&pdev->dev, "OF registration failed %d\n", err);
+ dma_async_device_unregister(dma_dev);
+ return err;
+ }
+
+ platform_set_drvdata(pdev, tdma);
+
+ return 0;
+}
+
+static int tegra_ahbdma_remove(struct platform_device *pdev)
+{
+ struct tegra_ahbdma *tdma = platform_get_drvdata(pdev);
+
+ of_dma_controller_free(pdev->dev.of_node);
+ dma_async_device_unregister(&tdma->dma_dev);
+ clk_disable_unprepare(tdma->clk);
+
+ return 0;
+}
+
+static const struct of_device_id tegra_ahbdma_of_match[] = {
+ { .compatible = "nvidia,tegra20-ahbdma" },
+ { },
+};
+MODULE_DEVICE_TABLE(of, tegra_ahbdma_of_match);
+
+static struct platform_driver tegra_ahbdma_driver = {
+ .driver = {
+ .name = "tegra-ahbdma",
+ .of_match_table = tegra_ahbdma_of_match,
+ },
+ .probe = tegra_ahbdma_probe,
+ .remove = tegra_ahbdma_remove,
+};
+module_platform_driver(tegra_ahbdma_driver);
+
+MODULE_DESCRIPTION("NVIDIA Tegra AHB DMA Controller driver");
+MODULE_AUTHOR("Dmitry Osipenko <digetx@xxxxxxxxx>");
+MODULE_LICENSE("GPL");
--
2.14.1