[PATCH v8 1/2] dmaengine: 8250_mtk_dma: add MediaTek uart DMA support

Long Cheng
2018-12-29T10:30:45Z

In DMA engine framework, add 8250 uart dma to support MediaTek uart.
If MediaTek uart enabled(SERIAL_8250_MT6577), and want to improve
the performance, can enable the function.

Signed-off-by: Long Cheng <long.cheng@mediatek.com>
---
drivers/dma/mediatek/8250_mtk_dma.c | 694 +++++++++++++++++++++++++++++++++++
drivers/dma/mediatek/Kconfig | 11 +
drivers/dma/mediatek/Makefile | 1 +
3 files changed, 706 insertions(+)
create mode 100644 drivers/dma/mediatek/8250_mtk_dma.c

diff --git a/drivers/dma/mediatek/8250_mtk_dma.c b/drivers/dma/mediatek/8250_mtk_dma.c
new file mode 100644
index 0000000..c4090f2
--- /dev/null
+++ b/drivers/dma/mediatek/8250_mtk_dma.c
@@ -0,0 +1,694 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * MediaTek 8250 DMA driver.
+ *
+ * Copyright (c) 2018 MediaTek Inc.
+ * Author: Long Cheng <long.cheng@mediatek.com>
+ */
+
+#include <linux/clk.h>
+#include <linux/dmaengine.h>
+#include <linux/dma-mapping.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/list.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_dma.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/pm_runtime.h>
+#include <linux/iopoll.h>
+
+#include "../virt-dma.h"
+
+#define MTK_UART_APDMA_CHANNELS (CONFIG_SERIAL_8250_NR_UARTS * 2)
+
+#define VFF_EN_B BIT(0)
+#define VFF_STOP_B BIT(0)
+#define VFF_FLUSH_B BIT(0)
+#define VFF_4G_SUPPORT_B BIT(0)
+#define VFF_RX_INT_EN0_B BIT(0) /*rx valid size >= vff thre*/
+#define VFF_RX_INT_EN1_B BIT(1)
+#define VFF_TX_INT_EN_B BIT(0) /*tx left size >= vff thre*/
+#define VFF_WARM_RST_B BIT(0)
+#define VFF_RX_INT_FLAG_CLR_B (BIT(0) | BIT(1))
+#define VFF_TX_INT_FLAG_CLR_B 0
+#define VFF_STOP_CLR_B 0
+#define VFF_FLUSH_CLR_B 0
+#define VFF_INT_EN_CLR_B 0
+#define VFF_4G_SUPPORT_CLR_B 0
+
+/* interrupt trigger level for tx */
+#define VFF_TX_THRE(n) ((n) * 7 / 8)
+/* interrupt trigger level for rx */
+#define VFF_RX_THRE(n) ((n) * 3 / 4)
+
+#define MTK_UART_APDMA_RING_SIZE 0xffffU
+/* invert this bit when wrap ring head again*/
+#define MTK_UART_APDMA_RING_WRAP 0x10000U
+
+#define VFF_INT_FLAG 0x00
+#define VFF_INT_EN 0x04
+#define VFF_EN 0x08
+#define VFF_RST 0x0c
+#define VFF_STOP 0x10
+#define VFF_FLUSH 0x14
+#define VFF_ADDR 0x1c
+#define VFF_LEN 0x24
+#define VFF_THRE 0x28
+#define VFF_WPT 0x2c
+#define VFF_RPT 0x30
+/*TX: the buffer size HW can read. RX: the buffer size SW can read.*/
+#define VFF_VALID_SIZE 0x3c
+/*TX: the buffer size SW can write. RX: the buffer size HW can write.*/
+#define VFF_LEFT_SIZE 0x40
+#define VFF_DEBUG_STATUS 0x50
+#define VFF_4G_SUPPORT 0x54
+
+struct mtk_uart_apdmadev {
+ struct dma_device ddev;
+ struct clk *clk;
+ bool support_33bits;
+ unsigned int dma_irq[MTK_UART_APDMA_CHANNELS];
+};
+
+struct mtk_uart_apdma_desc {
+ struct virt_dma_desc vd;
+
+ unsigned int avail_len;
+};
+
+struct mtk_chan {
+ struct virt_dma_chan vc;
+ struct dma_slave_config cfg;
+ void __iomem *base;
+ struct mtk_uart_apdma_desc *desc;
+
+ bool requested;
+
+ unsigned int rx_status;
+};
+
+static inline struct mtk_uart_apdmadev *
+to_mtk_uart_apdma_dev(struct dma_device *d)
+{
+ return container_of(d, struct mtk_uart_apdmadev, ddev);
+}
+
+static inline struct mtk_chan *to_mtk_uart_apdma_chan(struct dma_chan *c)
+{
+ return container_of(c, struct mtk_chan, vc.chan);
+}
+
+static inline struct mtk_uart_apdma_desc *to_mtk_uart_apdma_desc
+ (struct dma_async_tx_descriptor *t)
+{
+ return container_of(t, struct mtk_uart_apdma_desc, vd.tx);
+}
+
+static void mtk_uart_apdma_chan_write(struct mtk_chan *c,
+ unsigned int reg, unsigned int val)
+{
+ writel(val, c->base + reg);
+}
+
+static unsigned int
+mtk_uart_apdma_chan_read(struct mtk_chan *c, unsigned int reg)
+{
+ return readl(c->base + reg);
+}
+
+static void mtk_uart_apdma_desc_free(struct virt_dma_desc *vd)
+{
+ struct dma_chan *chan = vd->tx.chan;
+ struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
+
+ kfree(c->desc);
+ c->desc = NULL;
+}
+
+static void mtk_uart_apdma_start_tx(struct mtk_chan *c)
+{
+ unsigned int txcount = c->desc->avail_len;
+ unsigned int len, send, left, wpt, wrap;
+
+ if (mtk_uart_apdma_chan_read(c, VFF_LEFT_SIZE) == 0U) {
+ mtk_uart_apdma_chan_write(c, VFF_INT_EN, VFF_TX_INT_EN_B);
+ } else {
+ len = mtk_uart_apdma_chan_read(c, VFF_LEN);
+
+ while (((left = mtk_uart_apdma_chan_read(c,
+ VFF_LEFT_SIZE)) > 0U)
+ && (c->desc->avail_len != 0U)) {
+ send = min_t(unsigned int, left, c->desc->avail_len);
+ wpt = mtk_uart_apdma_chan_read(c, VFF_WPT);
+ wrap = wpt & MTK_UART_APDMA_RING_WRAP ?
+ 0U : MTK_UART_APDMA_RING_WRAP;
+
+ if ((wpt & (len - 1U)) + send < len)
+ mtk_uart_apdma_chan_write(c,
+ VFF_WPT, wpt + send);
+ else
+ mtk_uart_apdma_chan_write(c, VFF_WPT,
+ ((wpt + send) & (len - 1U))
+ | wrap);
+
+ c->desc->avail_len -= send;
+ }
+
+ if (txcount != c->desc->avail_len) {
+ mtk_uart_apdma_chan_write(c,
+ VFF_INT_EN, VFF_TX_INT_EN_B);
+ if (mtk_uart_apdma_chan_read(c,
+ VFF_FLUSH) == 0U)
+ mtk_uart_apdma_chan_write(c,
+ VFF_FLUSH, VFF_FLUSH_B);
+ }
+ }
+}
+
+static void mtk_uart_apdma_start_rx(struct mtk_chan *c)
+{
+ struct mtk_uart_apdma_desc *d = c->desc;
+ unsigned int rx_len, wg, rg, count;
+
+ if (mtk_uart_apdma_chan_read(c, VFF_VALID_SIZE) == 0U)
+ return;
+
+ if (d && vchan_next_desc(&c->vc)) {
+ rx_len = mtk_uart_apdma_chan_read(c, VFF_LEN);
+ rg = mtk_uart_apdma_chan_read(c, VFF_RPT);
+ wg = mtk_uart_apdma_chan_read(c, VFF_WPT);
+ count = ((rg ^ wg) & MTK_UART_APDMA_RING_WRAP) ?
+ ((wg & MTK_UART_APDMA_RING_SIZE) +
+ rx_len - (rg & MTK_UART_APDMA_RING_SIZE)) :
+ ((wg & MTK_UART_APDMA_RING_SIZE) -
+ (rg & MTK_UART_APDMA_RING_SIZE));
+
+ c->rx_status = count;
+ mtk_uart_apdma_chan_write(c, VFF_RPT, wg);
+
+ list_del(&d->vd.node);
+ vchan_cookie_complete(&d->vd);
+ }
+}
+
+static irqreturn_t mtk_uart_apdma_irq_handler(int irq, void *dev_id)
+{
+ struct dma_chan *chan = (struct dma_chan *)dev_id;
+ struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
+ struct mtk_uart_apdma_desc *d;
+ unsigned long flags;
+
+ spin_lock_irqsave(&c->vc.lock, flags);
+ switch (c->cfg.direction) {
+ case DMA_DEV_TO_MEM:
+ mtk_uart_apdma_chan_write(c,
+ VFF_INT_FLAG, VFF_RX_INT_FLAG_CLR_B);
+ mtk_uart_apdma_start_rx(c);
+ break;
+ case DMA_MEM_TO_DEV:
+ d = c->desc;
+
+ mtk_uart_apdma_chan_write(c,
+ VFF_INT_FLAG, VFF_TX_INT_FLAG_CLR_B);
+
+ if (d->avail_len != 0U) {
+ mtk_uart_apdma_start_tx(c);
+ } else {
+ list_del(&d->vd.node);
+ vchan_cookie_complete(&d->vd);
+ }
+ break;
+ default:
+ break;
+ }
+ spin_unlock_irqrestore(&c->vc.lock, flags);
+
+ return IRQ_HANDLED;
+}
+
+static int mtk_uart_apdma_alloc_chan_resources(struct dma_chan *chan)
+{
+ struct mtk_uart_apdmadev *mtkd = to_mtk_uart_apdma_dev(chan->device);
+ struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
+ u32 status;
+ int ret = -EBUSY;
+
+ pm_runtime_get_sync(mtkd->ddev.dev);
+
+ mtk_uart_apdma_chan_write(c, VFF_ADDR, 0);
+ mtk_uart_apdma_chan_write(c, VFF_THRE, 0);
+ mtk_uart_apdma_chan_write(c, VFF_LEN, 0);
+ mtk_uart_apdma_chan_write(c, VFF_RST, VFF_WARM_RST_B);
+
+ ret = readx_poll_timeout(readl,
+ c->base + VFF_EN,
+ status, status == 0, 10, 100);
+ if (ret) {
+ dev_err(c->vc.chan.device->dev,
+ "dma reset: fail, timeout\n");
+ goto exit;
+ }
+
+ if (!c->requested) {
+ c->requested = true;
+ ret = request_irq(mtkd->dma_irq[chan->chan_id],
+ mtk_uart_apdma_irq_handler,
+ IRQF_TRIGGER_NONE,
+ KBUILD_MODNAME, chan);
+ if (ret < 0) {
+ dev_err(chan->device->dev, "Can't request dma IRQ\n");
+ return -EINVAL;
+ }
+ }
+
+ if (mtkd->support_33bits)
+ mtk_uart_apdma_chan_write(c,
+ VFF_4G_SUPPORT, VFF_4G_SUPPORT_CLR_B);
+
+exit:
+ return ret;
+}
+
+static void mtk_uart_apdma_free_chan_resources(struct dma_chan *chan)
+{
+ struct mtk_uart_apdmadev *mtkd = to_mtk_uart_apdma_dev(chan->device);
+ struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
+
+ if (c->requested) {
+ c->requested = false;
+ free_irq(mtkd->dma_irq[chan->chan_id], chan);
+ }
+
+ tasklet_kill(&c->vc.task);
+
+ vchan_free_chan_resources(&c->vc);
+
+ pm_runtime_put_sync(mtkd->ddev.dev);
+}
+
+static enum dma_status mtk_uart_apdma_tx_status(struct dma_chan *chan,
+ dma_cookie_t cookie,
+ struct dma_tx_state *txstate)
+{
+ struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
+ enum dma_status ret;
+ unsigned long flags;
+
+ if (!txstate)
+ return DMA_ERROR;
+
+ ret = dma_cookie_status(chan, cookie, txstate);
+ spin_lock_irqsave(&c->vc.lock, flags);
+ if (ret == DMA_IN_PROGRESS) {
+ c->rx_status = mtk_uart_apdma_chan_read(c, VFF_RPT)
+ & MTK_UART_APDMA_RING_SIZE;
+ dma_set_residue(txstate, c->rx_status);
+ } else if (ret == DMA_COMPLETE && c->cfg.direction == DMA_DEV_TO_MEM) {
+ dma_set_residue(txstate, c->rx_status);
+ } else {
+ dma_set_residue(txstate, 0);
+ }
+ spin_unlock_irqrestore(&c->vc.lock, flags);
+
+ return ret;
+}
+
+/*
+ * dmaengine_prep_slave_single will call the function. and sglen is 1.
+ * 8250 uart using one ring buffer, and deal with one sg.
+ */
+static struct dma_async_tx_descriptor *mtk_uart_apdma_prep_slave_sg
+ (struct dma_chan *chan, struct scatterlist *sgl,
+ unsigned int sglen, enum dma_transfer_direction dir,
+ unsigned long tx_flags, void *context)
+{
+ struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
+ struct mtk_uart_apdma_desc *d;
+
+ if ((dir != DMA_DEV_TO_MEM) &&
+ (dir != DMA_MEM_TO_DEV)) {
+ dev_err(chan->device->dev, "bad direction\n");
+ return NULL;
+ }
+
+ /* Now allocate and setup the descriptor */
+ d = kzalloc(sizeof(*d), GFP_ATOMIC);
+ if (!d)
+ return NULL;
+
+ /* sglen is 1 */
+ d->avail_len = sg_dma_len(sgl);
+
+ return vchan_tx_prep(&c->vc, &d->vd, tx_flags);
+}
+
+static void mtk_uart_apdma_issue_pending(struct dma_chan *chan)
+{
+ struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
+ struct virt_dma_desc *vd;
+ unsigned long flags;
+
+ spin_lock_irqsave(&c->vc.lock, flags);
+ if (c->cfg.direction == DMA_DEV_TO_MEM) {
+ if (vchan_issue_pending(&c->vc) && !c->desc) {
+ vd = vchan_next_desc(&c->vc);
+ c->desc = to_mtk_uart_apdma_desc(&vd->tx);
+ mtk_uart_apdma_start_rx(c);
+ }
+ } else if (c->cfg.direction == DMA_MEM_TO_DEV) {
+ if (vchan_issue_pending(&c->vc) && !c->desc) {
+ vd = vchan_next_desc(&c->vc);
+ c->desc = to_mtk_uart_apdma_desc(&vd->tx);
+ mtk_uart_apdma_start_tx(c);
+ }
+ }
+ spin_unlock_irqrestore(&c->vc.lock, flags);
+}
+
+static int mtk_uart_apdma_slave_config(struct dma_chan *chan,
+ struct dma_slave_config *cfg)
+{
+ struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
+ struct mtk_uart_apdmadev *mtkd =
+ to_mtk_uart_apdma_dev(c->vc.chan.device);
+
+ c->cfg = *cfg;
+
+ if (cfg->direction == DMA_DEV_TO_MEM) {
+ unsigned int rx_len = cfg->src_addr_width * 1024;
+
+ mtk_uart_apdma_chan_write(c, VFF_ADDR, cfg->src_addr);
+ mtk_uart_apdma_chan_write(c, VFF_LEN, rx_len);
+ mtk_uart_apdma_chan_write(c, VFF_THRE, VFF_RX_THRE(rx_len));
+ mtk_uart_apdma_chan_write(c,
+ VFF_INT_EN, VFF_RX_INT_EN0_B
+ | VFF_RX_INT_EN1_B);
+ mtk_uart_apdma_chan_write(c, VFF_RPT, 0);
+ mtk_uart_apdma_chan_write(c,
+ VFF_INT_FLAG, VFF_RX_INT_FLAG_CLR_B);
+ mtk_uart_apdma_chan_write(c, VFF_EN, VFF_EN_B);
+ } else if (cfg->direction == DMA_MEM_TO_DEV) {
+ unsigned int tx_len = cfg->dst_addr_width * 1024;
+
+ mtk_uart_apdma_chan_write(c, VFF_ADDR, cfg->dst_addr);
+ mtk_uart_apdma_chan_write(c, VFF_LEN, tx_len);
+ mtk_uart_apdma_chan_write(c, VFF_THRE, VFF_TX_THRE(tx_len));
+ mtk_uart_apdma_chan_write(c, VFF_WPT, 0);
+ mtk_uart_apdma_chan_write(c,
+ VFF_INT_FLAG, VFF_TX_INT_FLAG_CLR_B);
+ mtk_uart_apdma_chan_write(c, VFF_EN, VFF_EN_B);
+ }
+
+ if (mtkd->support_33bits)
+ mtk_uart_apdma_chan_write(c, VFF_4G_SUPPORT, VFF_4G_SUPPORT_B);
+
+ if (mtk_uart_apdma_chan_read(c, VFF_EN) != VFF_EN_B) {
+ dev_err(chan->device->dev,
+ "config dma dir[%d] fail\n", cfg->direction);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int mtk_uart_apdma_terminate_all(struct dma_chan *chan)
+{
+ struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
+ unsigned long flags;
+ u32 status;
+ int ret;
+
+ spin_lock_irqsave(&c->vc.lock, flags);
+
+ mtk_uart_apdma_chan_write(c, VFF_FLUSH, VFF_FLUSH_CLR_B);
+ /* Wait for flush */
+ ret = readx_poll_timeout(readl,
+ c->base + VFF_FLUSH,
+ status,
+ (status & VFF_FLUSH_B) != VFF_FLUSH_B,
+ 10, 100);
+ if (ret)
+ dev_err(c->vc.chan.device->dev,
+ "dma stop: polling FLUSH fail, DEBUG=0x%x\n",
+ mtk_uart_apdma_chan_read(c, VFF_DEBUG_STATUS));
+
+ /*set stop as 1 -> wait until en is 0 -> set stop as 0*/
+ mtk_uart_apdma_chan_write(c, VFF_STOP, VFF_STOP_B);
+ ret = readx_poll_timeout(readl,
+ c->base + VFF_EN,
+ status, status == 0, 10, 100);
+ if (ret)
+ dev_err(c->vc.chan.device->dev,
+ "dma stop: polling VFF_EN fail, DEBUG=0x%x\n",
+ mtk_uart_apdma_chan_read(c, VFF_DEBUG_STATUS));
+
+ mtk_uart_apdma_chan_write(c, VFF_STOP, VFF_STOP_CLR_B);
+ mtk_uart_apdma_chan_write(c, VFF_INT_EN, VFF_INT_EN_CLR_B);
+
+ switch (c->cfg.direction) {
+ case DMA_DEV_TO_MEM:
+ mtk_uart_apdma_chan_write(c,
+ VFF_INT_FLAG, VFF_RX_INT_FLAG_CLR_B);
+ break;
+ case DMA_MEM_TO_DEV:
+ mtk_uart_apdma_chan_write(c,
+ VFF_INT_FLAG, VFF_TX_INT_FLAG_CLR_B);
+ break;
+ default:
+ break;
+ }
+
+ spin_unlock_irqrestore(&c->vc.lock, flags);
+
+ return 0;
+}
+
+static int mtk_uart_apdma_device_pause(struct dma_chan *chan)
+{
+ /* just for check caps pass */
+ return 0;
+}
+
+static int mtk_uart_apdma_device_resume(struct dma_chan *chan)
+{
+ /* just for check caps pass */
+ return 0;
+}
+
+static void mtk_uart_apdma_free(struct mtk_uart_apdmadev *mtkd)
+{
+ while (list_empty(&mtkd->ddev.channels) == 0) {
+ struct mtk_chan *c = list_first_entry(&mtkd->ddev.channels,
+ struct mtk_chan, vc.chan.device_node);
+
+ list_del(&c->vc.chan.device_node);
+ tasklet_kill(&c->vc.task);
+ }
+}
+
+static const struct of_device_id mtk_uart_apdma_match[] = {
+ { .compatible = "mediatek,mt6577-uart-dma", },
+ { /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, mtk_uart_apdma_match);
+
+static int mtk_uart_apdma_probe(struct platform_device *pdev)
+{
+ struct mtk_uart_apdmadev *mtkd;
+ struct resource *res;
+ struct mtk_chan *c;
+ unsigned int i;
+ int rc;
+
+ mtkd = devm_kzalloc(&pdev->dev, sizeof(*mtkd), GFP_KERNEL);
+ if (!mtkd)
+ return -ENOMEM;
+
+ mtkd->clk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(mtkd->clk)) {
+ dev_err(&pdev->dev, "No clock specified\n");
+ rc = PTR_ERR(mtkd->clk);
+ goto err_no_dma;
+ }
+
+ if (of_property_read_bool(pdev->dev.of_node, "dma-33bits")) {
+ dev_info(&pdev->dev, "Support dma 33bits\n");
+ mtkd->support_33bits = true;
+ }
+
+ rc = dma_set_mask_and_coherent(&pdev->dev,
+ DMA_BIT_MASK(32 | mtkd->support_33bits));
+ if (rc)
+ goto err_no_dma;
+
+ dma_cap_set(DMA_SLAVE, mtkd->ddev.cap_mask);
+ mtkd->ddev.device_alloc_chan_resources =
+ mtk_uart_apdma_alloc_chan_resources;
+ mtkd->ddev.device_free_chan_resources =
+ mtk_uart_apdma_free_chan_resources;
+ mtkd->ddev.device_tx_status = mtk_uart_apdma_tx_status;
+ mtkd->ddev.device_issue_pending = mtk_uart_apdma_issue_pending;
+ mtkd->ddev.device_prep_slave_sg = mtk_uart_apdma_prep_slave_sg;
+ mtkd->ddev.device_config = mtk_uart_apdma_slave_config;
+ mtkd->ddev.device_pause = mtk_uart_apdma_device_pause;
+ mtkd->ddev.device_resume = mtk_uart_apdma_device_resume;
+ mtkd->ddev.device_terminate_all = mtk_uart_apdma_terminate_all;
+ mtkd->ddev.src_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE);
+ mtkd->ddev.dst_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE);
+ mtkd->ddev.directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
+ mtkd->ddev.residue_granularity = DMA_RESIDUE_GRANULARITY_SEGMENT;
+ mtkd->ddev.dev = &pdev->dev;
+ INIT_LIST_HEAD(&mtkd->ddev.channels);
+
+ for (i = 0; i < MTK_UART_APDMA_CHANNELS; i++) {
+ c = devm_kzalloc(mtkd->ddev.dev, sizeof(*c), GFP_KERNEL);
+ if (!c) {
+ rc = -ENODEV;
+ goto err_no_dma;
+ }
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, i);
+ if (!res) {
+ rc = -ENODEV;
+ goto err_no_dma;
+ }
+
+ c->base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(c->base)) {
+ rc = PTR_ERR(c->base);
+ goto err_no_dma;
+ }
+ c->requested = false;
+ c->vc.desc_free = mtk_uart_apdma_desc_free;
+ vchan_init(&c->vc, &mtkd->ddev);
+
+ mtkd->dma_irq[i] = platform_get_irq(pdev, i);
+ if ((int)mtkd->dma_irq[i] < 0) {
+ dev_err(&pdev->dev, "failed to get IRQ[%d]\n", i);
+ rc = -EINVAL;
+ goto err_no_dma;
+ }
+ }
+
+ pm_runtime_enable(&pdev->dev);
+ pm_runtime_set_active(&pdev->dev);
+
+ rc = dma_async_device_register(&mtkd->ddev);
+ if (rc)
+ goto rpm_disable;
+
+ platform_set_drvdata(pdev, mtkd);
+
+ if (pdev->dev.of_node) {
+ /* Device-tree DMA controller registration */
+ rc = of_dma_controller_register(pdev->dev.of_node,
+ of_dma_xlate_by_chan_id,
+ mtkd);
+ if (rc)
+ goto dma_remove;
+ }
+
+ return rc;
+
+dma_remove:
+ dma_async_device_unregister(&mtkd->ddev);
+rpm_disable:
+ pm_runtime_disable(&pdev->dev);
+err_no_dma:
+ mtk_uart_apdma_free(mtkd);
+ return rc;
+}
+
+static int mtk_uart_apdma_remove(struct platform_device *pdev)
+{
+ struct mtk_uart_apdmadev *mtkd = platform_get_drvdata(pdev);
+
+ if (pdev->dev.of_node)
+ of_dma_controller_free(pdev->dev.of_node);
+
+ pm_runtime_disable(&pdev->dev);
+ pm_runtime_put_noidle(&pdev->dev);
+
+ dma_async_device_unregister(&mtkd->ddev);
+ mtk_uart_apdma_free(mtkd);
+
+ return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int mtk_uart_apdma_suspend(struct device *dev)
+{
+ struct mtk_uart_apdmadev *mtkd = dev_get_drvdata(dev);
+
+ if (!pm_runtime_suspended(dev))
+ clk_disable_unprepare(mtkd->clk);
+
+ return 0;
+}
+
+static int mtk_uart_apdma_resume(struct device *dev)
+{
+ int ret;
+ struct mtk_uart_apdmadev *mtkd = dev_get_drvdata(dev);
+
+ if (!pm_runtime_suspended(dev)) {
+ ret = clk_prepare_enable(mtkd->clk);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+#endif /* CONFIG_PM_SLEEP */
+
+#ifdef CONFIG_PM
+static int mtk_uart_apdma_runtime_suspend(struct device *dev)
+{
+ struct mtk_uart_apdmadev *mtkd = dev_get_drvdata(dev);
+
+ clk_disable_unprepare(mtkd->clk);
+
+ return 0;
+}
+
+static int mtk_uart_apdma_runtime_resume(struct device *dev)
+{
+ int ret;
+ struct mtk_uart_apdmadev *mtkd = dev_get_drvdata(dev);
+
+ ret = clk_prepare_enable(mtkd->clk);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+#endif /* CONFIG_PM */
+
+static const struct dev_pm_ops mtk_uart_apdma_pm_ops = {
+ SET_SYSTEM_SLEEP_PM_OPS(mtk_uart_apdma_suspend, mtk_uart_apdma_resume)
+ SET_RUNTIME_PM_OPS(mtk_uart_apdma_runtime_suspend,
+ mtk_uart_apdma_runtime_resume, NULL)
+};
+
+static struct platform_driver mtk_uart_apdma_driver = {
+ .probe = mtk_uart_apdma_probe,
+ .remove = mtk_uart_apdma_remove,
+ .driver = {
+ .name = KBUILD_MODNAME,
+ .pm = &mtk_uart_apdma_pm_ops,
+ .of_match_table = of_match_ptr(mtk_uart_apdma_match),
+ },
+};
+
+module_platform_driver(mtk_uart_apdma_driver);
+
+MODULE_DESCRIPTION("MediaTek UART APDMA Controller Driver");
+MODULE_AUTHOR("Long Cheng <long.cheng@mediatek.com>");
+MODULE_LICENSE("GPL v2");
+
diff --git a/drivers/dma/mediatek/Kconfig b/drivers/dma/mediatek/Kconfig
index 27bac0b..1a523c87 100644
--- a/drivers/dma/mediatek/Kconfig
+++ b/drivers/dma/mediatek/Kconfig
@@ -1,4 +1,15 @@

+config DMA_MTK_UART
+ tristate "MediaTek SoCs APDMA support for UART"
+ depends on OF && SERIAL_8250_MT6577
+ select DMA_ENGINE
+ select DMA_VIRTUAL_CHANNELS
+ help
+ Support for the UART DMA engine found on MediaTek MTK SoCs.
+ when SERIAL_8250_MT6577 is enabled, and if you want to use DMA,
+ you can enable the config. the DMA engine can only be used
+ with MediaTek SoCs.
+
config MTK_HSDMA
tristate "MediaTek High-Speed DMA controller support"
depends on ARCH_MEDIATEK || COMPILE_TEST
diff --git a/drivers/dma/mediatek/Makefile b/drivers/dma/mediatek/Makefile
index 6e778f8..2f2efd9 100644
--- a/drivers/dma/mediatek/Makefile
+++ b/drivers/dma/mediatek/Makefile
@@ -1 +1,2 @@
+obj-$(CONFIG_DMA_MTK_UART) += 8250_mtk_dma.o
obj-$(CONFIG_MTK_HSDMA) += mtk-hsdma.o
--
1.7.9.5