i2c: sh_mobile: add DMA support (2d09581b) · Commits · 戴 / test

Documentation/devicetree/bindings/i2c/i2c-sh_mobile.txt

+5 −0

Original line number	Diff line number	Diff line
		@@ -19,6 +19,11 @@ Required properties:

		Optional properties:
		- clock-frequency : frequency of bus clock in Hz. Default 100kHz if unset.
		- dmas : Must contain a list of two references to DMA
		specifiers, one for transmission, and one for
		reception.
		- dma-names : Must contain a list of two DMA names, "tx" and "rx".


		Pinctrl properties might be needed, too. See there.

drivers/i2c/busses/i2c-sh_mobile.c

+185 −10

Original line number	Diff line number	Diff line
		/*
		* SuperH Mobile I2C Controller
		*
		* Copyright (C) 2014 Wolfram Sang <wsa@sang-engineering.com>
		*
		* Copyright (C) 2008 Magnus Damm
		*
		* Portions of the code based on out-of-tree driver i2c-sh7343.c
		@@ -18,6 +20,8 @@

		#include <linux/clk.h>
		#include <linux/delay.h>
		#include <linux/dmaengine.h>
		#include <linux/dma-mapping.h>
		#include <linux/err.h>
		#include <linux/i2c.h>
		#include <linux/i2c/i2c-sh_mobile.h>
		@@ -110,6 +114,7 @@ enum sh_mobile_i2c_op {
		OP_TX_FIRST,
		OP_TX,
		OP_TX_STOP,
		OP_TX_STOP_DATA,
		OP_TX_TO_RX,
		OP_RX,
		OP_RX_STOP,
		@@ -134,6 +139,11 @@ struct sh_mobile_i2c_data {
		int pos;
		int sr;
		bool send_stop;

		struct dma_chan *dma_tx;
		struct dma_chan *dma_rx;
		struct scatterlist sg;
		enum dma_data_direction dma_direction;
		};

		struct sh_mobile_dt_config {
		@@ -171,6 +181,8 @@ struct sh_mobile_dt_config {

		#define ICIC_ICCLB8 0x80
		#define ICIC_ICCHB8 0x40
		#define ICIC_TDMAE 0x20
		#define ICIC_RDMAE 0x10
		#define ICIC_ALE 0x08
		#define ICIC_TACKE 0x04
		#define ICIC_WAITE 0x02
		@@ -332,8 +344,10 @@ static unsigned char i2c_op(struct sh_mobile_i2c_data *pd,
		case OP_TX: /* write data */
		iic_wr(pd, ICDR, data);
		break;
		case OP_TX_STOP: /* write data and issue a stop afterwards */
		case OP_TX_STOP_DATA: /* write data and issue a stop afterwards */
		iic_wr(pd, ICDR, data);
		/* fallthrough */
		case OP_TX_STOP: /* issue a stop */
		iic_wr(pd, ICCR, pd->send_stop ? ICCR_ICE \| ICCR_TRS
		: ICCR_ICE \| ICCR_TRS \| ICCR_BBSY);
		break;
		@@ -389,13 +403,17 @@ static int sh_mobile_i2c_isr_tx(struct sh_mobile_i2c_data *pd)
		{
		unsigned char data;

		if (pd->pos == pd->msg->len)
		if (pd->pos == pd->msg->len) {
		/* Send stop if we haven't yet (DMA case) */
		if (pd->send_stop && (iic_rd(pd, ICCR) & ICCR_BBSY))
		i2c_op(pd, OP_TX_STOP, 0);
		return 1;
		}

		sh_mobile_i2c_get_data(pd, &data);

		if (sh_mobile_i2c_is_last_byte(pd))
		i2c_op(pd, OP_TX_STOP, data);
		i2c_op(pd, OP_TX_STOP_DATA, data);
		else if (sh_mobile_i2c_is_first_byte(pd))
		i2c_op(pd, OP_TX_FIRST, data);
		else
		@@ -450,7 +468,7 @@ static irqreturn_t sh_mobile_i2c_isr(int irq, void *dev_id)
		struct platform_device *dev = dev_id;
		struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev);
		unsigned char sr;
		int wakeup;
		int wakeup = 0;

		sr = iic_rd(pd, ICSR);
		pd->sr \|= sr; /* remember state */
		@@ -459,15 +477,21 @@ static irqreturn_t sh_mobile_i2c_isr(int irq, void *dev_id)
		(pd->msg->flags & I2C_M_RD) ? "read" : "write",
		pd->pos, pd->msg->len);

		if (sr & (ICSR_AL \| ICSR_TACK)) {
		/* Kick off TxDMA after preface was done */
		if (pd->dma_direction == DMA_TO_DEVICE && pd->pos == 0)
		iic_set_clr(pd, ICIC, ICIC_TDMAE, 0);
		else if (sr & (ICSR_AL \| ICSR_TACK))
		/* don't interrupt transaction - continue to issue stop */
		iic_wr(pd, ICSR, sr & ~(ICSR_AL \| ICSR_TACK));
		wakeup = 0;
		} else if (pd->msg->flags & I2C_M_RD)
		else if (pd->msg->flags & I2C_M_RD)
		wakeup = sh_mobile_i2c_isr_rx(pd);
		else
		wakeup = sh_mobile_i2c_isr_tx(pd);

		/* Kick off RxDMA after preface was done */
		if (pd->dma_direction == DMA_FROM_DEVICE && pd->pos == 1)
		iic_set_clr(pd, ICIC, ICIC_RDMAE, 0);

		if (sr & ICSR_WAIT) /* TODO: add delay here to support slow acks */
		iic_wr(pd, ICSR, sr & ~ICSR_WAIT);

		@@ -482,6 +506,79 @@ static irqreturn_t sh_mobile_i2c_isr(int irq, void *dev_id)
		return IRQ_HANDLED;
		}

		static void sh_mobile_i2c_cleanup_dma(struct sh_mobile_i2c_data *pd)
		{
		if (pd->dma_direction == DMA_NONE)
		return;
		else if (pd->dma_direction == DMA_FROM_DEVICE)
		dmaengine_terminate_all(pd->dma_rx);
		else if (pd->dma_direction == DMA_TO_DEVICE)
		dmaengine_terminate_all(pd->dma_tx);

		dma_unmap_single(pd->dev, sg_dma_address(&pd->sg),
		pd->msg->len, pd->dma_direction);

		pd->dma_direction = DMA_NONE;
		}

		static void sh_mobile_i2c_dma_callback(void *data)
		{
		struct sh_mobile_i2c_data *pd = data;

		dma_unmap_single(pd->dev, sg_dma_address(&pd->sg),
		pd->msg->len, pd->dma_direction);

		pd->dma_direction = DMA_NONE;
		pd->pos = pd->msg->len;

		iic_set_clr(pd, ICIC, 0, ICIC_TDMAE \| ICIC_RDMAE);
		}

		static void sh_mobile_i2c_xfer_dma(struct sh_mobile_i2c_data *pd)
		{
		bool read = pd->msg->flags & I2C_M_RD;
		enum dma_data_direction dir = read ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
		struct dma_chan *chan = read ? pd->dma_rx : pd->dma_tx;
		struct dma_async_tx_descriptor *txdesc;
		dma_addr_t dma_addr;
		dma_cookie_t cookie;

		if (!chan)
		return;

		dma_addr = dma_map_single(pd->dev, pd->msg->buf, pd->msg->len, dir);
		if (dma_mapping_error(pd->dev, dma_addr)) {
		dev_dbg(pd->dev, "dma map failed, using PIO\n");
		return;
		}

		sg_dma_len(&pd->sg) = pd->msg->len;
		sg_dma_address(&pd->sg) = dma_addr;

		pd->dma_direction = dir;

		txdesc = dmaengine_prep_slave_sg(chan, &pd->sg, 1,
		read ? DMA_DEV_TO_MEM : DMA_MEM_TO_DEV,
		DMA_PREP_INTERRUPT \| DMA_CTRL_ACK);
		if (!txdesc) {
		dev_dbg(pd->dev, "dma prep slave sg failed, using PIO\n");
		sh_mobile_i2c_cleanup_dma(pd);
		return;
		}

		txdesc->callback = sh_mobile_i2c_dma_callback;
		txdesc->callback_param = pd;

		cookie = dmaengine_submit(txdesc);
		if (dma_submit_error(cookie)) {
		dev_dbg(pd->dev, "submitting dma failed, using PIO\n");
		sh_mobile_i2c_cleanup_dma(pd);
		return;
		}

		dma_async_issue_pending(chan);
		}

		static int start_ch(struct sh_mobile_i2c_data pd, struct i2c_msg usr_msg,
		bool do_init)
		{
		@@ -506,6 +603,9 @@ static int start_ch(struct sh_mobile_i2c_data pd, struct i2c_msg usr_msg,
		pd->pos = -1;
		pd->sr = 0;

		if (pd->msg->len > 8)
		sh_mobile_i2c_xfer_dma(pd);

		/* Enable all interrupts to begin with */
		iic_wr(pd, ICIC, ICIC_DTEE \| ICIC_WAITE \| ICIC_ALE \| ICIC_TACKE);
		return 0;
		@@ -589,6 +689,9 @@ static int sh_mobile_i2c_xfer(struct i2c_adapter *adapter,
		5 * HZ);
		if (!k) {
		dev_err(pd->dev, "Transfer request timed out\n");
		if (pd->dma_direction != DMA_NONE)
		sh_mobile_i2c_cleanup_dma(pd);

		err = -ETIMEDOUT;
		break;
		}
		@@ -639,6 +742,62 @@ static const struct of_device_id sh_mobile_i2c_dt_ids[] = {
		};
		MODULE_DEVICE_TABLE(of, sh_mobile_i2c_dt_ids);

		static int sh_mobile_i2c_request_dma_chan(struct device *dev, enum dma_transfer_direction dir,
		dma_addr_t port_addr, struct dma_chan **chan_ptr)
		{
		dma_cap_mask_t mask;
		struct dma_chan *chan;
		struct dma_slave_config cfg;
		char *chan_name = dir == DMA_MEM_TO_DEV ? "tx" : "rx";
		int ret;

		dma_cap_zero(mask);
		dma_cap_set(DMA_SLAVE, mask);
		*chan_ptr = NULL;

		chan = dma_request_slave_channel_reason(dev, chan_name);
		if (IS_ERR(chan)) {
		ret = PTR_ERR(chan);
		dev_dbg(dev, "request_channel failed for %s (%d)\n", chan_name, ret);
		return ret;
		}

		memset(&cfg, 0, sizeof(cfg));
		cfg.direction = dir;
		if (dir == DMA_MEM_TO_DEV) {
		cfg.dst_addr = port_addr;
		cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
		} else {
		cfg.src_addr = port_addr;
		cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
		}

		ret = dmaengine_slave_config(chan, &cfg);
		if (ret) {
		dev_dbg(dev, "slave_config failed for %s (%d)\n", chan_name, ret);
		dma_release_channel(chan);
		return ret;
		}

		*chan_ptr = chan;

		dev_dbg(dev, "got DMA channel for %s\n", chan_name);
		return 0;
		}

		static void sh_mobile_i2c_release_dma(struct sh_mobile_i2c_data *pd)
		{
		if (pd->dma_tx) {
		dma_release_channel(pd->dma_tx);
		pd->dma_tx = NULL;
		}

		if (pd->dma_rx) {
		dma_release_channel(pd->dma_rx);
		pd->dma_rx = NULL;
		}
		}

		static int sh_mobile_i2c_hook_irqs(struct platform_device *dev)
		{
		struct resource *res;
		@@ -725,6 +884,21 @@ static int sh_mobile_i2c_probe(struct platform_device *dev)
		if (ret)
		return ret;

		/* Init DMA */
		sg_init_table(&pd->sg, 1);
		pd->dma_direction = DMA_NONE;
		ret = sh_mobile_i2c_request_dma_chan(pd->dev, DMA_DEV_TO_MEM,
		res->start + ICDR, &pd->dma_rx);
		if (ret == -EPROBE_DEFER)
		return ret;

		ret = sh_mobile_i2c_request_dma_chan(pd->dev, DMA_MEM_TO_DEV,
		res->start + ICDR, &pd->dma_tx);
		if (ret == -EPROBE_DEFER) {
		sh_mobile_i2c_release_dma(pd);
		return ret;
		}

		/* Enable Runtime PM for this device.
		*
		* Also tell the Runtime PM core to ignore children
		@@ -756,6 +930,7 @@ static int sh_mobile_i2c_probe(struct platform_device *dev)

		ret = i2c_add_numbered_adapter(adap);
		if (ret < 0) {
		sh_mobile_i2c_release_dma(pd);
		dev_err(&dev->dev, "cannot add numbered adapter\n");
		return ret;
		}
		@@ -772,6 +947,7 @@ static int sh_mobile_i2c_remove(struct platform_device *dev)
		struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev);

		i2c_del_adapter(&pd->adap);
		sh_mobile_i2c_release_dma(pd);
		pm_runtime_disable(&dev->dev);
		return 0;
		}
		@@ -808,16 +984,15 @@ static int __init sh_mobile_i2c_adap_init(void)
		{
		return platform_driver_register(&sh_mobile_i2c_driver);
		}
		subsys_initcall(sh_mobile_i2c_adap_init);

		static void __exit sh_mobile_i2c_adap_exit(void)
		{
		platform_driver_unregister(&sh_mobile_i2c_driver);
		}

		subsys_initcall(sh_mobile_i2c_adap_init);
		module_exit(sh_mobile_i2c_adap_exit);

		MODULE_DESCRIPTION("SuperH Mobile I2C Bus Controller driver");
		MODULE_AUTHOR("Magnus Damm");
		MODULE_AUTHOR("Magnus Damm and Wolfram Sang");
		MODULE_LICENSE("GPL v2");
		MODULE_ALIAS("platform:i2c-sh_mobile");

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