Re: [PATCH v6 07/10] drm/mediatek: add dsi transfer function

CK Hu
2016-08-05T10:08:25Z

Hi, YT:

On Thu, 2016-08-04 at 19:07 +0800, YT Shen wrote:
> From: shaoming chen <shaoming.chen@mediatek.com>
>
> add dsi read/write commands for transfer function
>
> Signed-off-by: shaoming chen <shaoming.chen@mediatek.com>
> ---
> drivers/gpu/drm/mediatek/mtk_dsi.c | 261 ++++++++++++++++++++++++++++++++++++
> 1 file changed, 261 insertions(+)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
> index eea6192..4541f59 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> @@ -24,6 +24,7 @@
> #include <linux/of_graph.h>
> #include <linux/phy/phy.h>
> #include <linux/platform_device.h>
> +#include <video/mipi_display.h>
> #include <video/videomode.h>
>
> #include "mtk_drm_ddp_comp.h"
> @@ -81,8 +82,16 @@
> #define DSI_HBP_WC 0x54
> #define DSI_HFP_WC 0x58
>
> +#define DSI_CMDQ_SIZE 0x60
> +#define CMDQ_SIZE 0x3f
> +
> #define DSI_HSTX_CKL_WC 0x64
>
> +#define DSI_RX_DATA0 0x74
> +#define DSI_RX_DATA1 0x78
> +#define DSI_RX_DATA2 0x7c
> +#define DSI_RX_DATA3 0x80
> +
> #define DSI_RACK 0x84
> #define RACK BIT(0)
>
> @@ -118,8 +127,25 @@
> #define CLK_HS_POST (0xff << 8)
> #define CLK_HS_EXIT (0xff << 16)
>
> +#define DSI_CMDQ0 0x180
> +
> #define NS_TO_CYCLE(n, c) ((n) / (c) + (((n) % (c)) ? 1 : 0))
>
> +#define MTK_DSI_HOST_IS_READ(type) \
> + ((type == MIPI_DSI_GENERIC_READ_REQUEST_0_PARAM) || \
> + (type == MIPI_DSI_GENERIC_READ_REQUEST_1_PARAM) || \
> + (type == MIPI_DSI_GENERIC_READ_REQUEST_2_PARAM) || \
> + (type == MIPI_DSI_DCS_READ))
> +
> +#define MTK_DSI_HOST_IS_WRITE(type) \
> + ((type == MIPI_DSI_GENERIC_SHORT_WRITE_0_PARAM) || \
> + (type == MIPI_DSI_GENERIC_SHORT_WRITE_1_PARAM) || \
> + (type == MIPI_DSI_GENERIC_SHORT_WRITE_2_PARAM) || \
> + (type == MIPI_DSI_DCS_SHORT_WRITE) || \
> + (type == MIPI_DSI_DCS_SHORT_WRITE_PARAM) || \
> + (type == MIPI_DSI_GENERIC_LONG_WRITE) || \
> + (type == MIPI_DSI_DCS_LONG_WRITE))
> +
> struct phy;
>
> struct mtk_dsi {
> @@ -149,6 +175,13 @@ struct mtk_dsi {
> int irq_data;
> };
>
> +struct dsi_rxtx_data {
> + u8 byte0;
> + u8 byte1;
> + u8 byte2;
> + u8 byte3;
> +};
> +
> static wait_queue_head_t _dsi_irq_wait_queue;
>
> static inline struct mtk_dsi *encoder_to_dsi(struct drm_encoder *e)
> @@ -799,9 +832,237 @@ static int mtk_dsi_host_detach(struct mipi_dsi_host *host,
> return 0;
> }
>
> +static void mtk_dsi_wait_for_idle(struct mtk_dsi *dsi)
> +{
> + u32 timeout_ms = 500000; /* total 1s ~ 2s timeout */
> +
> + while (timeout_ms--) {
> + if (!(readl(dsi->regs + DSI_INTSTA) & DSI_BUSY))
> + break;
> +
> + usleep_range(2, 4);
> + }
> +
> + if (timeout_ms == 0) {
> + dev_info(dsi->dev, "polling dsi wait not busy timeout!\n");
> +
> + mtk_dsi_enable(dsi);
> + mtk_dsi_reset_engine(dsi);
> + }
> +}
> +
> +static void mtk_dsi_wait_for_cmd_done(struct mtk_dsi *dsi)
> +{
> + s32 ret = 0;
> + unsigned long timeout = msecs_to_jiffies(500);
> +
> + dsi->irq_data &= ~CMD_DONE_INT_FLAG;

You should move this clearing of flag before mtk_dsi_start().

> +
> + ret = wait_event_interruptible_timeout(_dsi_irq_wait_queue,
> + dsi->irq_data & CMD_DONE_INT_FLAG, timeout);
> + if (ret == 0) {
> + dev_info(dsi->dev, "dsi wait engine cmd done fail\n");
> +
> + mtk_dsi_enable(dsi);
> + mtk_dsi_reset_engine(dsi);
> + }
> +}
> +
> +static void mtk_dsi_cmdq(struct mtk_dsi *dsi, const struct mipi_dsi_msg *msg)
> +{
> + const char *tx_buf = msg->tx_buf;
> + u32 reg_val, i;
> + u16 wc16;
> + u8 config, data0, data1, type;
> +
> + if (MTK_DSI_HOST_IS_READ(type)) {

'type' is used before assigned.

> + config = 4;
> + data0 = tx_buf[0];
> +
> + if (msg->rx_len < 3)
> + type = MIPI_DSI_DCS_READ;
> + else
> + type = MIPI_DSI_GENERIC_READ_REQUEST_1_PARAM;
> +
> + data1 = 0;
> + reg_val = (data1 << 24) | (data0 << 16) | (type << 8) | config;
> +
> + writel(reg_val, dsi->regs + DSI_CMDQ0);
> + mtk_dsi_mask(dsi, DSI_CMDQ_SIZE, CMDQ_SIZE, 1);

I think this part looks like 'else' part. The difference is type and
config. I think type should be msg->type and you can independently set
BIT(2) of config.

> + } else if (msg->tx_len > 2) { /* send long packet */
> + config = 2;
> + type = msg->type;
> + wc16 = msg->tx_len;
> +
> + reg_val = (wc16 << 16) | (type << 8) | config;
> +
> + writel(reg_val, dsi->regs + DSI_CMDQ0);
> +
> + for (i = 0; i < msg->tx_len; i++)
> + writeb(tx_buf[i], dsi->regs + DSI_CMDQ0 + 4 + i);
> +
> + mtk_dsi_mask(dsi, DSI_CMDQ_SIZE, CMDQ_SIZE,
> + 1 + (msg->tx_len + 3) / 4);
> + } else { /* send short packet */
> + config = 0;
> + data0 = tx_buf[0];
> +
> + if (msg->tx_len == 2) {
> + type = MIPI_DSI_DCS_SHORT_WRITE_PARAM;

Why do you not set type as msg->type? This behavior looks like you
modify transfer type, but is this acceptable?

> + data1 = tx_buf[1];
> + } else {
> + type = MIPI_DSI_DCS_SHORT_WRITE;
> + data1 = 0;
> + }
> +
> + reg_val = (data1 << 24) | (data0 << 16) | (type << 8) | config;
> +
> + writel(reg_val, dsi->regs + DSI_CMDQ0);
> + mtk_dsi_mask(dsi, DSI_CMDQ_SIZE, CMDQ_SIZE, 1);
> + }
> +}
> +
> +static ssize_t mtk_dsi_host_read_cmd(struct mtk_dsi *dsi,
> + const struct mipi_dsi_msg *msg)
> +{
> + u8 max_try_count = 5;
> + u32 recv_cnt;
> + struct dsi_rxtx_data read_data[4];
> + s32 ret;
> + unsigned long timeout = msecs_to_jiffies(2000);
> +
> + u8 *buffer = msg->rx_buf;
> + u8 buffer_size = msg->rx_len;
> + u8 type;
> +
> + if (readl(dsi->regs + DSI_MODE_CTRL) & MODE) {
> + dev_info(dsi->dev, "dsi engine is not command mode\n");
> + return -1;
> + }
> +
> + if (!buffer) {
> + dev_info(dsi->dev, "dsi receive buffer size may be NULL\n");
> + return -1;
> + }
> +
> + do {
> + if (max_try_count == 0) {
> + dev_info(dsi->dev, "dsi engine read counter has been maxinum\n");
> + return -1;
> + }
> +
> + max_try_count--;
> + recv_cnt = 0;
> +
> + mtk_dsi_wait_for_idle(dsi);
> + mtk_dsi_cmdq(dsi, msg);
> +
> + dsi->irq_data &= ~LPRX_RD_RDY_INT_FLAG;
> +
> + mtk_dsi_start(dsi);
> +
> + /* 2s timeout*/
> + ret = wait_event_interruptible_timeout(_dsi_irq_wait_queue,
> + dsi->irq_data & LPRX_RD_RDY_INT_FLAG, timeout);
> + if (ret == 0) {
> + dev_info(dsi->dev, "Wait DSI read ready timeout!!!\n");
> +
> + mtk_dsi_enable(dsi);
> + mtk_dsi_reset_engine(dsi);
> +
> + return ret;
> + }

This waiting code looks like mtk_dsi_wait_for_cmd_done(). You may modify
this function to

int mtk_dsi_wait_for_irq_flag(struct mtk_dsi *dsi, u32 flag, unsigned
long timeout);

> +
> + *(u32 *)(&read_data[0]) = readl(dsi->regs + DSI_RX_DATA0);
> + *(u32 *)(&read_data[1]) = readl(dsi->regs + DSI_RX_DATA1);
> + *(u32 *)(&read_data[2]) = readl(dsi->regs + DSI_RX_DATA2);
> + *(u32 *)(&read_data[3]) = readl(dsi->regs + DSI_RX_DATA3);

You may rewrite this as

for (i = 0; i < 16; i++)
*((u8 *)read_data + i) = readb(dsi->regs + DSI_RX_DATA0 + i);

> +
> + type = read_data[0].byte0;
> +
> + if (type == MIPI_DSI_RX_GENERIC_LONG_READ_RESPONSE ||
> + type == MIPI_DSI_RX_DCS_LONG_READ_RESPONSE) {
> + /*
> + * Data ID(1 byte) + Word Count(2 bytes) + ECC(1 byte) +
> + * data 0 + ...+ data WC-1 + CHECKSUM (2 bytes)
> + */
> + recv_cnt = read_data[0].byte1 + read_data[0].byte2 * 16;
> + dev_info(dsi->dev, "long packet size: %d\n", recv_cnt);
> +
> + /*
> + * the buffer size is 16 bytes once, so the data payload
> + * is, 16 - bytes(data ID + WC + ECC + CHECKSUM), if
> + * over 10 bytes, it will be read again
> + */
> + if (recv_cnt > 10)
> + recv_cnt = 10;
> +
> + if (recv_cnt > buffer_size)
> + recv_cnt = buffer_size;
> +
> + memcpy(buffer, &read_data[1], recv_cnt);
> + } else if (type == MIPI_DSI_RX_GENERIC_SHORT_READ_RESPONSE_1BYTE ||
> + type == MIPI_DSI_RX_GENERIC_SHORT_READ_RESPONSE_2BYTE ||
> + type == MIPI_DSI_RX_DCS_SHORT_READ_RESPONSE_1BYTE ||
> + type == MIPI_DSI_RX_DCS_SHORT_READ_RESPONSE_2BYTE) {
> + if (type == MIPI_DSI_RX_GENERIC_SHORT_READ_RESPONSE_1BYTE ||
> + type == MIPI_DSI_RX_DCS_SHORT_READ_RESPONSE_1BYTE)
> + recv_cnt = 1;
> + else
> + recv_cnt = 2;
> +
> + if (recv_cnt > buffer_size)
> + recv_cnt = buffer_size;
> +
> + memcpy(buffer, &read_data[0].byte1, recv_cnt);

I think you may rewrite this 'if-else if' part as follow to make things
more clearly.

static u32 get_recv_cnt(u8 type, struct dsi_rxtx_data *read_data)
{
switch(type) {
case MIPI_DSI_RX_GENERIC_SHORT_READ_RESPONSE_1BYTE:
case MIPI_DSI_RX_DCS_SHORT_READ_RESPONSE_1BYTE:
return 1;
case MIPI_DSI_RX_GENERIC_SHORT_READ_RESPONSE_2BYTE:
case MIPI_DSI_RX_DCS_SHORT_READ_RESPONSE_2BYTE:
return 2;
case MIPI_DSI_RX_GENERIC_LONG_READ_RESPONSE:
case MIPI_DSI_RX_DCS_LONG_READ_RESPONSE:
return read_data->byte1 + read_data->byte2 * 16;
}

return 0;
}

recv_cnt = get_recv_cnt(type, read_data);

if (recv_cnt > 2)
src_addr = &read_data[1];
else
src_addr = &read_data[0].byte1;

if (recv_cnt > 10)
recv_cnt = 10;
if (recv_cnt > buffer_size)
recv_cnt = buffer_size;
if (recv_cnt)
memcpy(buffer, src_addr, recv_cnt);

> + } else if (type == MIPI_DSI_RX_ACKNOWLEDGE_AND_ERROR_REPORT) {
> + dev_info(dsi->dev, "packet type is 0x02, try again\n");
> + } else {
> + dev_info(dsi->dev, "packet type(0x%x) cannot be non-recognize\n",
> + type);
> +
> + return 0;
> + }
> + } while (type == MIPI_DSI_RX_ACKNOWLEDGE_AND_ERROR_REPORT);
> +
> + dev_info(dsi->dev, "dsi get %d byte data from the panel address(0x%x)\n",
> + recv_cnt, *((u8 *)(msg->tx_buf)));
> +
> + return recv_cnt;
> +}
> +
> +static ssize_t mtk_dsi_host_write_cmd(struct mtk_dsi *dsi,
> + const struct mipi_dsi_msg *msg)
> +{
> + mtk_dsi_wait_for_idle(dsi);
> +
> + mtk_dsi_cmdq(dsi, msg);
> +
> + mtk_dsi_start(dsi);
> + mtk_dsi_wait_for_cmd_done(dsi);
> +
> + return 0;
> +}
> +
> +static ssize_t mtk_dsi_host_transfer(struct mipi_dsi_host *host,
> + const struct mipi_dsi_msg *msg)
> +{
> + struct mtk_dsi *dsi = host_to_dsi(host);
> + u8 type = msg->type;
> + ssize_t ret = 0;
> +
> + if (MTK_DSI_HOST_IS_READ(type))
> + ret = mtk_dsi_host_read_cmd(dsi, msg);
> + else if (MTK_DSI_HOST_IS_WRITE(type))
> + ret = mtk_dsi_host_write_cmd(dsi, msg);
> +
> + return ret;
> +}
> +
> static const struct mipi_dsi_host_ops mtk_dsi_ops = {
> .attach = mtk_dsi_host_attach,
> .detach = mtk_dsi_host_detach,
> + .transfer = mtk_dsi_host_transfer,
> };
>
> static int mtk_dsi_bind(struct device *dev, struct device *master, void *data)

Regards,
CK