> From: Clark Wang <xiaoning.wang@xxxxxxx>
> Sent: Wednesday, March 17, 2021 2:54 PM
>
> Add eDMA receive and send mode support.
> Support to read and write data larger than 256 bytes in one frame.
>
> Signed-off-by: Clark Wang <xiaoning.wang@xxxxxxx>
> Reviewed-by: Li Jun <jun.li@xxxxxxx>
> ---
> drivers/i2c/busses/i2c-imx-lpi2c.c | 291 ++++++++++++++++++++++++++++-
Pease update dt-binding first
> 1 file changed, 289 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-imx-lpi2c.c
> b/drivers/i2c/busses/i2c-imx-lpi2c.c
> index 1e26672d47bf..6d920bf0dbd4 100644
> --- a/drivers/i2c/busses/i2c-imx-lpi2c.c
> +++ b/drivers/i2c/busses/i2c-imx-lpi2c.c
> @@ -8,6 +8,8 @@
> #include <linux/clk.h>
> #include <linux/completion.h>
> #include <linux/delay.h>
> +#include <linux/dmaengine.h>
> +#include <linux/dma-mapping.h>
> #include <linux/err.h>
> #include <linux/errno.h>
> #include <linux/i2c.h>
> @@ -31,6 +33,7 @@
> #define LPI2C_MCR 0x10 /* i2c contrl register */
> #define LPI2C_MSR 0x14 /* i2c status register */
> #define LPI2C_MIER 0x18 /* i2c interrupt enable */
> +#define LPI2C_MDER 0x1C /* i2c DMA enable */
> #define LPI2C_MCFGR0 0x20 /* i2c master configuration */
> #define LPI2C_MCFGR1 0x24 /* i2c master configuration */
> #define LPI2C_MCFGR2 0x28 /* i2c master configuration */
> @@ -72,11 +75,15 @@
> #define MCFGR1_AUTOSTOP BIT(8)
> #define MCFGR1_IGNACK BIT(9)
> #define MRDR_RXEMPTY BIT(14)
> +#define MDER_TDDE BIT(0)
> +#define MDER_RDDE BIT(1)
>
> #define I2C_CLK_RATIO 24 / 59
> #define CHUNK_DATA 256
>
> #define I2C_PM_TIMEOUT 1000 /* ms */
> +#define I2C_DMA_THRESHOLD 16 /* bytes */
> +#define I2C_USE_PIO (-150)
Can you clarify a bit why need using this strange value?
>
> enum lpi2c_imx_mode {
> STANDARD, /* <=100Kbps */
> @@ -95,6 +102,7 @@ enum lpi2c_imx_pincfg {
>
> struct lpi2c_imx_struct {
> struct i2c_adapter adapter;
> + resource_size_t phy_addr;
> int irq;
> struct clk *clk_per;
> struct clk *clk_ipg;
> @@ -114,6 +122,17 @@ struct lpi2c_imx_struct {
> struct pinctrl *pinctrl;
> struct pinctrl_state *pinctrl_pins_default;
> struct pinctrl_state *pinctrl_pins_gpio;
> +
> + bool can_use_dma;
> + bool using_dma;
> + bool xferred;
> + struct i2c_msg *msg;
> + dma_addr_t dma_addr;
> + struct dma_chan *dma_tx;
> + struct dma_chan *dma_rx;
> + enum dma_data_direction dma_direction;
> + u8 *dma_buf;
> + unsigned int dma_len;
> };
>
> static void lpi2c_imx_intctrl(struct lpi2c_imx_struct *lpi2c_imx, @@ -289,6
> +308,9 @@ static int lpi2c_imx_master_enable(struct lpi2c_imx_struct
> *lpi2c_imx)
> if (ret)
> goto rpm_put;
>
> + if (lpi2c_imx->can_use_dma)
> + writel(MDER_TDDE | MDER_RDDE, lpi2c_imx->base + LPI2C_MDER);
> +
> temp = readl(lpi2c_imx->base + LPI2C_MCR);
> temp |= MCR_MEN;
> writel(temp, lpi2c_imx->base + LPI2C_MCR); @@ -462,6 +484,154 @@
> static void lpi2c_imx_read(struct lpi2c_imx_struct *lpi2c_imx,
> lpi2c_imx_intctrl(lpi2c_imx, MIER_RDIE | MIER_NDIE); }
>
> +static void lpi2c_dma_unmap(struct lpi2c_imx_struct *lpi2c_imx) {
> + struct dma_chan *chan = lpi2c_imx->dma_direction ==
> DMA_FROM_DEVICE
> + ? lpi2c_imx->dma_rx : lpi2c_imx->dma_tx;
> +
> + dma_unmap_single(chan->device->dev, lpi2c_imx->dma_addr,
> + lpi2c_imx->dma_len, lpi2c_imx->dma_direction);
> +
> + lpi2c_imx->dma_direction = DMA_NONE;
> +}
> +
> +static void lpi2c_cleanup_dma(struct lpi2c_imx_struct *lpi2c_imx) {
> + if (lpi2c_imx->dma_direction == DMA_NONE)
> + return;
> + else if (lpi2c_imx->dma_direction == DMA_FROM_DEVICE)
> + dmaengine_terminate_all(lpi2c_imx->dma_rx);
> + else if (lpi2c_imx->dma_direction == DMA_TO_DEVICE)
> + dmaengine_terminate_all(lpi2c_imx->dma_tx);
> +
> + lpi2c_dma_unmap(lpi2c_imx);
> +}
> +
> +static void lpi2c_dma_callback(void *data) {
> + struct lpi2c_imx_struct *lpi2c_imx = (struct lpi2c_imx_struct *)data;
> +
> + lpi2c_dma_unmap(lpi2c_imx);
> + writel(GEN_STOP << 8, lpi2c_imx->base + LPI2C_MTDR);
> + lpi2c_imx->xferred = true;
> +
> + complete(&lpi2c_imx->complete);
> +}
> +
> +static int lpi2c_dma_submit(struct lpi2c_imx_struct *lpi2c_imx,
> + struct i2c_msg *msg)
> +{
> + bool read = msg->flags & I2C_M_RD;
> + enum dma_data_direction dir = read ? DMA_FROM_DEVICE :
> DMA_TO_DEVICE;
> + struct dma_chan *chan = read ? lpi2c_imx->dma_rx : lpi2c_imx->dma_tx;
> + struct dma_async_tx_descriptor *txdesc;
> + dma_cookie_t cookie;
> +
> + lpi2c_imx->dma_len = read ? msg->len - 1 : msg->len;
> + lpi2c_imx->msg = msg;
> + lpi2c_imx->dma_direction = dir;
> +
> + if (IS_ERR(chan))
> + return PTR_ERR(chan);
> +
> + lpi2c_imx->dma_addr = dma_map_single(chan->device->dev,
> + lpi2c_imx->dma_buf,
> + lpi2c_imx->dma_len, dir);
> + if (dma_mapping_error(chan->device->dev, lpi2c_imx->dma_addr)) {
> + dev_err(&lpi2c_imx->adapter.dev, "dma map failed, use pio\n");
> + return -EINVAL;
> + }
> +
> + txdesc = dmaengine_prep_slave_single(chan, lpi2c_imx->dma_addr,
> + lpi2c_imx->dma_len, read ?
> + DMA_DEV_TO_MEM : DMA_MEM_TO_DEV,
> + DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
> + if (!txdesc) {
> + dev_err(&lpi2c_imx->adapter.dev, "dma prep slave sg failed, use
> pio\n");
> + lpi2c_cleanup_dma(lpi2c_imx);
> + return -EINVAL;
> + }
> +
> + reinit_completion(&lpi2c_imx->complete);
> + txdesc->callback = lpi2c_dma_callback;
> + txdesc->callback_param = (void *)lpi2c_imx;
> +
> + cookie = dmaengine_submit(txdesc);
> + if (dma_submit_error(cookie)) {
> + dev_err(&lpi2c_imx->adapter.dev, "submitting dma failed, use
> pio\n");
> + lpi2c_cleanup_dma(lpi2c_imx);
> + return -EINVAL;
> + }
> +
> + lpi2c_imx_intctrl(lpi2c_imx, MIER_NDIE);
> +
> + dma_async_issue_pending(chan);
> +
> + return 0;
> +}
> +
> +static bool is_use_dma(struct lpi2c_imx_struct *lpi2c_imx, struct
> +i2c_msg *msg) {
> + if (!lpi2c_imx->can_use_dma)
> + return false;
> +
> + if (msg->len < I2C_DMA_THRESHOLD)
> + return false;
> +
> + return true;
> +}
> +
> +static int lpi2c_imx_push_rx_cmd(struct lpi2c_imx_struct *lpi2c_imx,
> + struct i2c_msg *msg)
> +{
> + unsigned int temp, rx_remain;
> + unsigned long orig_jiffies = jiffies;
> +
> + if ((msg->flags & I2C_M_RD)) {
> + rx_remain = msg->len;
> + do {
> + temp = rx_remain > CHUNK_DATA ?
> + CHUNK_DATA - 1 : rx_remain - 1;
> + temp |= (RECV_DATA << 8);
> + while ((readl(lpi2c_imx->base + LPI2C_MFSR) & 0xff) > 2) {
> + if (time_after(jiffies, orig_jiffies + msecs_to_jiffies(1000))) {
> + dev_dbg(&lpi2c_imx->adapter.dev, "txfifo empty
> timeout\n");
> + if (lpi2c_imx->adapter.bus_recovery_info)
> + i2c_recover_bus(&lpi2c_imx->adapter);
> + return -ETIMEDOUT;
> + }
> + schedule();
> + }
> + writel(temp, lpi2c_imx->base + LPI2C_MTDR);
> + rx_remain = rx_remain - (temp & 0xff) - 1;
> + } while (rx_remain > 0);
> + }
> +
> + return 0;
> +}
> +
> +static int lpi2c_dma_xfer(struct lpi2c_imx_struct *lpi2c_imx,
> + struct i2c_msg *msg)
> +{
> + int result;
> +
> + result = lpi2c_dma_submit(lpi2c_imx, msg);
> + if (!result) {
> + result = lpi2c_imx_push_rx_cmd(lpi2c_imx, msg);
> + if (result)
> + return result;
> + result = lpi2c_imx_msg_complete(lpi2c_imx);
> + return result;
> + }
> +
> + /* DMA xfer failed, try to use PIO, clean up dma things */
> + i2c_put_dma_safe_msg_buf(lpi2c_imx->dma_buf, lpi2c_imx->msg,
> + lpi2c_imx->xferred);
> + lpi2c_cleanup_dma(lpi2c_imx);
> +
> + return I2C_USE_PIO;
> +}
> +
> static int lpi2c_imx_xfer(struct i2c_adapter *adapter,
> struct i2c_msg *msgs, int num)
> {
> @@ -474,6 +644,9 @@ static int lpi2c_imx_xfer(struct i2c_adapter *adapter,
> return result;
>
> for (i = 0; i < num; i++) {
> + lpi2c_imx->xferred = false;
> + lpi2c_imx->using_dma = false;
> +
> result = lpi2c_imx_start(lpi2c_imx, &msgs[i]);
> if (result)
> goto disable;
> @@ -482,9 +655,24 @@ static int lpi2c_imx_xfer(struct i2c_adapter *adapter,
> if (num == 1 && msgs[0].len == 0)
> goto stop;
>
> + if (is_use_dma(lpi2c_imx, &msgs[i])) {
> + lpi2c_imx->using_dma = true;
> +
> + writel(0x1, lpi2c_imx->base + LPI2C_MFCR);
> +
> + lpi2c_imx->dma_buf = i2c_get_dma_safe_msg_buf(&msgs[i],
> + I2C_DMA_THRESHOLD);
> + if (lpi2c_imx->dma_buf) {
> + result = lpi2c_dma_xfer(lpi2c_imx, &msgs[i]);
> + if (result != I2C_USE_PIO)
> + goto stop;
> + }
> + }
> +
> + lpi2c_imx->using_dma = false;
> lpi2c_imx->delivered = 0;
> lpi2c_imx->msglen = msgs[i].len;
> - init_completion(&lpi2c_imx->complete);
> + reinit_completion(&lpi2c_imx->complete);
>
> if (msgs[i].flags & I2C_M_RD)
> lpi2c_imx_read(lpi2c_imx, &msgs[i]); @@ -503,7 +691,16 @@
> static int lpi2c_imx_xfer(struct i2c_adapter *adapter,
> }
>
> stop:
> - lpi2c_imx_stop(lpi2c_imx);
> + if (!lpi2c_imx->using_dma)
> + lpi2c_imx_stop(lpi2c_imx);
> + else {
> + i2c_put_dma_safe_msg_buf(lpi2c_imx->dma_buf, lpi2c_imx->msg,
> + lpi2c_imx->xferred);
> + if (result) {
> + lpi2c_cleanup_dma(lpi2c_imx);
> + writel(GEN_STOP << 8, lpi2c_imx->base + LPI2C_MTDR);
> + }
> + }
>
> temp = readl(lpi2c_imx->base + LPI2C_MSR);
> if ((temp & MSR_NDF) && !result)
> @@ -528,6 +725,10 @@ static irqreturn_t lpi2c_imx_isr(int irq, void *dev_id)
> temp = readl(lpi2c_imx->base + LPI2C_MSR);
>
> if (temp & MSR_NDF) {
> + if (lpi2c_imx->using_dma) {
> + lpi2c_cleanup_dma(lpi2c_imx);
> + writel(GEN_STOP << 8, lpi2c_imx->base + LPI2C_MTDR);
> + }
> complete(&lpi2c_imx->complete);
> goto ret;
> }
> @@ -623,20 +824,94 @@ static const struct of_device_id
> lpi2c_imx_of_match[] = { }; MODULE_DEVICE_TABLE(of,
> lpi2c_imx_of_match);
>
> +static void lpi2c_dma_exit(struct lpi2c_imx_struct *lpi2c_imx) {
> + if (lpi2c_imx->dma_rx) {
> + dma_release_channel(lpi2c_imx->dma_rx);
> + lpi2c_imx->dma_rx = NULL;
> + }
> +
> + if (lpi2c_imx->dma_tx) {
> + dma_release_channel(lpi2c_imx->dma_tx);
> + lpi2c_imx->dma_tx = NULL;
> + }
> +}
> +
> +static int lpi2c_dma_init(struct device *dev,
> + struct lpi2c_imx_struct *lpi2c_imx) {
> + int ret;
> + struct dma_slave_config dma_sconfig;
> +
> + /* Prepare for TX DMA: */
> + lpi2c_imx->dma_tx = dma_request_chan(dev, "tx");
> + if (IS_ERR(lpi2c_imx->dma_tx)) {
> + ret = PTR_ERR(lpi2c_imx->dma_tx);
> + dev_err(dev, "can't get the TX DMA channel, error %d!\n", ret);
> + lpi2c_imx->dma_tx = NULL;
> + goto err;
> + }
> +
> + dma_sconfig.dst_addr = lpi2c_imx->phy_addr + LPI2C_MTDR;
> + dma_sconfig.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
> + dma_sconfig.dst_maxburst = 1;
> + dma_sconfig.direction = DMA_MEM_TO_DEV;
> + ret = dmaengine_slave_config(lpi2c_imx->dma_tx, &dma_sconfig);
> + if (ret < 0) {
> + dev_err(dev, "can't configure tx channel (%d)\n", ret);
> + goto fail_tx;
> + }
> +
> + /* Prepare for RX DMA: */
> + lpi2c_imx->dma_rx = dma_request_chan(dev, "rx");
> + if (IS_ERR(lpi2c_imx->dma_rx)) {
> + ret = PTR_ERR(lpi2c_imx->dma_rx);
> + dev_err(dev, "can't get the RX DMA channel, error %d\n", ret);
> + lpi2c_imx->dma_rx = NULL;
> + goto fail_tx;
> + }
> +
> + dma_sconfig.src_addr = lpi2c_imx->phy_addr + LPI2C_MRDR;
> + dma_sconfig.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
> + dma_sconfig.src_maxburst = 1;
> + dma_sconfig.direction = DMA_DEV_TO_MEM;
> + ret = dmaengine_slave_config(lpi2c_imx->dma_rx, &dma_sconfig);
> + if (ret < 0) {
> + dev_err(dev, "can't configure rx channel (%d)\n", ret);
> + goto fail_rx;
> + }
> +
> + lpi2c_imx->can_use_dma = true;
> + lpi2c_imx->using_dma = false;
> +
> + return 0;
> +fail_rx:
> + dma_release_channel(lpi2c_imx->dma_rx);
> +fail_tx:
> + dma_release_channel(lpi2c_imx->dma_tx);
> +err:
> + lpi2c_dma_exit(lpi2c_imx);
> + lpi2c_imx->can_use_dma = false;
> + return ret;
> +}
> +
> static int lpi2c_imx_probe(struct platform_device *pdev) {
> struct lpi2c_imx_struct *lpi2c_imx;
> unsigned int temp;
> int ret;
> + struct resource *res;
>
> lpi2c_imx = devm_kzalloc(&pdev->dev, sizeof(*lpi2c_imx), GFP_KERNEL);
> if (!lpi2c_imx)
> return -ENOMEM;
>
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> lpi2c_imx->base = devm_platform_ioremap_resource(pdev, 0);
> if (IS_ERR(lpi2c_imx->base))
> return PTR_ERR(lpi2c_imx->base);
>
> + lpi2c_imx->phy_addr = (dma_addr_t)res->start;
> lpi2c_imx->irq = platform_get_irq(pdev, 0);
> if (lpi2c_imx->irq < 0)
> return lpi2c_imx->irq;
> @@ -691,6 +966,18 @@ static int lpi2c_imx_probe(struct platform_device
> *pdev)
> if (ret == -EPROBE_DEFER)
> goto rpm_disable;
>
> + /* Init DMA */
> + lpi2c_imx->dma_direction = DMA_NONE;
> + lpi2c_imx->dma_rx = lpi2c_imx->dma_tx = NULL;
Unnecessary line
> + ret = lpi2c_dma_init(&pdev->dev, lpi2c_imx);
> + if (ret) {
> + dev_err_probe(&pdev->dev, ret, "dma setup error %d, use pio\n",
> ret);
> + if (ret == -EPROBE_DEFER)
> + goto rpm_disable;
> + }
> +
> + init_completion(&lpi2c_imx->complete);
> +
> ret = i2c_add_adapter(&lpi2c_imx->adapter);
> if (ret)
> goto rpm_disable;
> --
> 2.25.1
