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Commit 9135408c authored by Long Cheng's avatar Long Cheng Committed by Vinod Koul
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dmaengine: mediatek: Add MediaTek UART APDMA support 



Add 8250 UART APDMA to support MediaTek UART. If MediaTek UART is
enabled by SERIAL_8250_MT6577, and we can enable this driver to offload
the UART device moving bytes.

Signed-off-by: default avatarLong Cheng <long.cheng@mediatek.com>
Signed-off-by: default avatarSean Wang <sean.wang@mediatek.com>
Signed-off-by: default avatarVinod Koul <vkoul@kernel.org>
parent 2fe5575f

drivers/dma/mediatek/Kconfig

+11 −0
Original line number Diff line number Diff line
@@ -24,3 +24,14 @@ config MTK_CQDMA 


	  This controller provides the channels which is dedicated to

	  memory-to-memory transfer to offload from CPU.



config MTK_UART_APDMA

	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.

drivers/dma/mediatek/Makefile

+1 −0
Original line number Diff line number Diff line 
obj-$(CONFIG_MTK_UART_APDMA) += mtk-uart-apdma.o

obj-$(CONFIG_MTK_HSDMA) += mtk-hsdma.o

obj-$(CONFIG_MTK_CQDMA) += mtk-cqdma.o

drivers/dma/mediatek/mtk-uart-apdma.c

0 → 100644
+666 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

/*

 * MediaTek UART APDMA driver.

 *

 * Copyright (c) 2019 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/iopoll.h>

#include <linux/kernel.h>

#include <linux/list.h>

#include <linux/module.h>

#include <linux/of_device.h>

#include <linux/of_dma.h>

#include <linux/platform_device.h>

#include <linux/pm_runtime.h>

#include <linux/slab.h>

#include <linux/spinlock.h>



#include "../virt-dma.h"



/* The default number of virtual channel */

#define MTK_UART_APDMA_NR_VCHANS	8



#define VFF_EN_B		BIT(0)

#define VFF_STOP_B		BIT(0)

#define VFF_FLUSH_B		BIT(0)

#define VFF_4G_EN_B		BIT(0)

/* rx valid size >=  vff thre */

#define VFF_RX_INT_EN_B		(BIT(0) | BIT(1))

/* tx left size >= vff thre */

#define VFF_TX_INT_EN_B		BIT(0)

#define VFF_WARM_RST_B		BIT(0)

#define VFF_RX_INT_CLR_B	(BIT(0) | BIT(1))

#define VFF_TX_INT_CLR_B	0

#define VFF_STOP_CLR_B		0

#define VFF_EN_CLR_B		0

#define VFF_INT_EN_CLR_B	0

#define VFF_4G_SUPPORT_CLR_B	0



/*

 * interrupt trigger level for tx

 * if threshold is n, no polling is required to start tx.

 * otherwise need polling VFF_FLUSH.

 */

#define VFF_TX_THRE(n)		(n)

/* interrupt trigger level for rx */

#define VFF_RX_THRE(n)		((n) * 3 / 4)



#define VFF_RING_SIZE	0xffff

/* invert this bit when wrap ring head again */

#define VFF_RING_WRAP	0x10000



#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_requests;

};



struct mtk_uart_apdma_desc {

	struct virt_dma_desc vd;



	dma_addr_t addr;

	unsigned int avail_len;

};



struct mtk_chan {

	struct virt_dma_chan vc;

	struct dma_slave_config	cfg;

	struct mtk_uart_apdma_desc *desc;

	enum dma_transfer_direction dir;



	void __iomem *base;

	unsigned int irq;



	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_write(struct mtk_chan *c,

			       unsigned int reg, unsigned int val)

{

	writel(val, c->base + reg);

}



static unsigned int mtk_uart_apdma_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);

}



static void mtk_uart_apdma_start_tx(struct mtk_chan *c)

{

	struct mtk_uart_apdmadev *mtkd =

				to_mtk_uart_apdma_dev(c->vc.chan.device);

	struct mtk_uart_apdma_desc *d = c->desc;

	unsigned int wpt, vff_sz;



	vff_sz = c->cfg.dst_port_window_size;

	if (!mtk_uart_apdma_read(c, VFF_LEN)) {

		mtk_uart_apdma_write(c, VFF_ADDR, d->addr);

		mtk_uart_apdma_write(c, VFF_LEN, vff_sz);

		mtk_uart_apdma_write(c, VFF_THRE, VFF_TX_THRE(vff_sz));

		mtk_uart_apdma_write(c, VFF_WPT, 0);

		mtk_uart_apdma_write(c, VFF_INT_FLAG, VFF_TX_INT_CLR_B);



		if (mtkd->support_33bits)

			mtk_uart_apdma_write(c, VFF_4G_SUPPORT, VFF_4G_EN_B);

	}



	mtk_uart_apdma_write(c, VFF_EN, VFF_EN_B);

	if (mtk_uart_apdma_read(c, VFF_EN) != VFF_EN_B)

		dev_err(c->vc.chan.device->dev, "Enable TX fail\n");



	if (!mtk_uart_apdma_read(c, VFF_LEFT_SIZE)) {

		mtk_uart_apdma_write(c, VFF_INT_EN, VFF_TX_INT_EN_B);

		return;

	}



	wpt = mtk_uart_apdma_read(c, VFF_WPT);



	wpt += c->desc->avail_len;

	if ((wpt & VFF_RING_SIZE) == vff_sz)

		wpt = (wpt & VFF_RING_WRAP) ^ VFF_RING_WRAP;



	/* Let DMA start moving data */

	mtk_uart_apdma_write(c, VFF_WPT, wpt);



	/* HW auto set to 0 when left size >= threshold */

	mtk_uart_apdma_write(c, VFF_INT_EN, VFF_TX_INT_EN_B);

	if (!mtk_uart_apdma_read(c, VFF_FLUSH))

		mtk_uart_apdma_write(c, VFF_FLUSH, VFF_FLUSH_B);

}



static void mtk_uart_apdma_start_rx(struct mtk_chan *c)

{

	struct mtk_uart_apdmadev *mtkd =

				to_mtk_uart_apdma_dev(c->vc.chan.device);

	struct mtk_uart_apdma_desc *d = c->desc;

	unsigned int vff_sz;



	vff_sz = c->cfg.src_port_window_size;

	if (!mtk_uart_apdma_read(c, VFF_LEN)) {

		mtk_uart_apdma_write(c, VFF_ADDR, d->addr);

		mtk_uart_apdma_write(c, VFF_LEN, vff_sz);

		mtk_uart_apdma_write(c, VFF_THRE, VFF_RX_THRE(vff_sz));

		mtk_uart_apdma_write(c, VFF_RPT, 0);

		mtk_uart_apdma_write(c, VFF_INT_FLAG, VFF_RX_INT_CLR_B);



		if (mtkd->support_33bits)

			mtk_uart_apdma_write(c, VFF_4G_SUPPORT, VFF_4G_EN_B);

	}



	mtk_uart_apdma_write(c, VFF_INT_EN, VFF_RX_INT_EN_B);

	mtk_uart_apdma_write(c, VFF_EN, VFF_EN_B);

	if (mtk_uart_apdma_read(c, VFF_EN) != VFF_EN_B)

		dev_err(c->vc.chan.device->dev, "Enable RX fail\n");

}



static void mtk_uart_apdma_tx_handler(struct mtk_chan *c)

{

	struct mtk_uart_apdma_desc *d = c->desc;



	mtk_uart_apdma_write(c, VFF_INT_FLAG, VFF_TX_INT_CLR_B);

	mtk_uart_apdma_write(c, VFF_INT_EN, VFF_INT_EN_CLR_B);

	mtk_uart_apdma_write(c, VFF_EN, VFF_EN_CLR_B);



	list_del(&d->vd.node);

	vchan_cookie_complete(&d->vd);

}



static void mtk_uart_apdma_rx_handler(struct mtk_chan *c)

{

	struct mtk_uart_apdma_desc *d = c->desc;

	unsigned int len, wg, rg;

	int cnt;



	mtk_uart_apdma_write(c, VFF_INT_FLAG, VFF_RX_INT_CLR_B);



	if (!mtk_uart_apdma_read(c, VFF_VALID_SIZE))

		return;



	mtk_uart_apdma_write(c, VFF_EN, VFF_EN_CLR_B);

	mtk_uart_apdma_write(c, VFF_INT_EN, VFF_INT_EN_CLR_B);



	len = c->cfg.src_port_window_size;

	rg = mtk_uart_apdma_read(c, VFF_RPT);

	wg = mtk_uart_apdma_read(c, VFF_WPT);

	cnt = (wg & VFF_RING_SIZE) - (rg & VFF_RING_SIZE);



	/*

	 * The buffer is ring buffer. If wrap bit different,

	 * represents the start of the next cycle for WPT

	 */

	if ((rg ^ wg) & VFF_RING_WRAP)

		cnt += len;



	c->rx_status = d->avail_len - cnt;

	mtk_uart_apdma_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);

	unsigned long flags;



	spin_lock_irqsave(&c->vc.lock, flags);

	if (c->dir == DMA_DEV_TO_MEM)

		mtk_uart_apdma_rx_handler(c);

	else if (c->dir == DMA_MEM_TO_DEV)

		mtk_uart_apdma_tx_handler(c);

	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);

	unsigned int status;

	int ret;



	ret = pm_runtime_get_sync(mtkd->ddev.dev);

	if (ret < 0) {

		pm_runtime_put_noidle(chan->device->dev);

		return ret;

	}



	mtk_uart_apdma_write(c, VFF_ADDR, 0);

	mtk_uart_apdma_write(c, VFF_THRE, 0);

	mtk_uart_apdma_write(c, VFF_LEN, 0);

	mtk_uart_apdma_write(c, VFF_RST, VFF_WARM_RST_B);



	ret = readx_poll_timeout(readl, c->base + VFF_EN,

			  status, !status, 10, 100);

	if (ret)

		return ret;



	ret = request_irq(c->irq, 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_write(c, VFF_4G_SUPPORT, VFF_4G_SUPPORT_CLR_B);



	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);



	free_irq(c->irq, 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;



	ret = dma_cookie_status(chan, cookie, txstate);

	if (!txstate)

		return ret;



	dma_set_residue(txstate, c->rx_status);



	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 (!is_slave_direction(dir) || sglen != 1)

		return NULL;



	/* Now allocate and setup the descriptor */

	d = kzalloc(sizeof(*d), GFP_ATOMIC);

	if (!d)

		return NULL;



	d->avail_len = sg_dma_len(sgl);

	d->addr = sg_dma_address(sgl);

	c->dir = dir;



	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 (vchan_issue_pending(&c->vc)) {

		vd = vchan_next_desc(&c->vc);

		c->desc = to_mtk_uart_apdma_desc(&vd->tx);



		if (c->dir == DMA_DEV_TO_MEM)

			mtk_uart_apdma_start_rx(c);

		else if (c->dir == DMA_MEM_TO_DEV)

			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 *config)

{

	struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);



	memcpy(&c->cfg, config, sizeof(*config));



	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;

	unsigned int status;

	LIST_HEAD(head);

	int ret;



	mtk_uart_apdma_write(c, VFF_FLUSH, VFF_FLUSH_B);



	ret = readx_poll_timeout(readl, c->base + VFF_FLUSH,

			  status, status != VFF_FLUSH_B, 10, 100);

	if (ret)

		dev_err(c->vc.chan.device->dev, "flush: fail, status=0x%x\n",

			mtk_uart_apdma_read(c, VFF_DEBUG_STATUS));



	/*

	 * Stop need 3 steps.

	 * 1. set stop to 1

	 * 2. wait en to 0

	 * 3. set stop as 0

	 */

	mtk_uart_apdma_write(c, VFF_STOP, VFF_STOP_B);

	ret = readx_poll_timeout(readl, c->base + VFF_EN,

			  status, !status, 10, 100);

	if (ret)

		dev_err(c->vc.chan.device->dev, "stop: fail, status=0x%x\n",

			mtk_uart_apdma_read(c, VFF_DEBUG_STATUS));



	mtk_uart_apdma_write(c, VFF_STOP, VFF_STOP_CLR_B);

	mtk_uart_apdma_write(c, VFF_INT_EN, VFF_INT_EN_CLR_B);



	if (c->dir == DMA_DEV_TO_MEM)

		mtk_uart_apdma_write(c, VFF_INT_FLAG, VFF_RX_INT_CLR_B);

	else if (c->dir == DMA_MEM_TO_DEV)

		mtk_uart_apdma_write(c, VFF_INT_FLAG, VFF_TX_INT_CLR_B);



	synchronize_irq(c->irq);



	spin_lock_irqsave(&c->vc.lock, flags);

	vchan_get_all_descriptors(&c->vc, &head);

	vchan_dma_desc_free_list(&c->vc, &head);

	spin_unlock_irqrestore(&c->vc.lock, flags);



	return 0;

}



static int mtk_uart_apdma_device_pause(struct dma_chan *chan)

{

	struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);

	unsigned long flags;



	spin_lock_irqsave(&c->vc.lock, flags);



	mtk_uart_apdma_write(c, VFF_EN, VFF_EN_CLR_B);

	mtk_uart_apdma_write(c, VFF_INT_EN, VFF_INT_EN_CLR_B);



	synchronize_irq(c->irq);



	spin_unlock_irqrestore(&c->vc.lock, flags);



	return 0;

}



static void mtk_uart_apdma_free(struct mtk_uart_apdmadev *mtkd)

{

	while (!list_empty(&mtkd->ddev.channels)) {

		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 device_node *np = pdev->dev.of_node;

	struct mtk_uart_apdmadev *mtkd;

	int bit_mask = 32, rc;

	struct resource *res;

	struct mtk_chan *c;

	unsigned int i;



	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);

		return rc;

	}



	if (of_property_read_bool(np, "mediatek,dma-33bits"))

		mtkd->support_33bits = true;



	if (mtkd->support_33bits)

		bit_mask = 33;



	rc = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(bit_mask));

	if (rc)

		return rc;



	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_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);



	mtkd->dma_requests = MTK_UART_APDMA_NR_VCHANS;

	if (of_property_read_u32(np, "dma-requests", &mtkd->dma_requests)) {

		dev_info(&pdev->dev,

			 "Using %u as missing dma-requests property\n",

			 MTK_UART_APDMA_NR_VCHANS);

	}



	for (i = 0; i < mtkd->dma_requests; 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->vc.desc_free = mtk_uart_apdma_desc_free;

		vchan_init(&c->vc, &mtkd->ddev);



		rc = platform_get_irq(pdev, i);

		if (rc < 0) {

			dev_err(&pdev->dev, "failed to get IRQ[%d]\n", i);

			goto err_no_dma;

		}

		c->irq = rc;

	}



	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);



	/* Device-tree DMA controller registration */

	rc = of_dma_controller_register(np, 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);



	of_dma_controller_free(pdev->dev.of_node);



	mtk_uart_apdma_free(mtkd);



	dma_async_device_unregister(&mtkd->ddev);



	pm_runtime_disable(&pdev->dev);



	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");