From 72957f48aaaa4e62bff22af81b5d96ca6bd0f492 Mon Sep 17 00:00:00 2001 From: Linus Walleij Date: Fri, 14 Aug 2020 21:44:51 +0200 Subject: [PATCH] drm/mcde: Retry DSI read/write transactions The vendor driver makes a few retries on read DSI transactions, something that is needed especially in case of read (such as reading the panel MTP ID) while the panel is running in video mode. This happens on the Samsung s6e63m0 panel on the Golden device. Retry reads and writes alike three times. Signed-off-by: Linus Walleij Reviewed-by: Stephan Gerhold Cc: Stephan Gerhold Link: https://patchwork.freedesktop.org/patch/msgid/20200814194451.3494294-1-linus.walleij@linaro.org --- drivers/gpu/drm/mcde/mcde_dsi.c | 158 +++++++++++++++++++------------- 1 file changed, 92 insertions(+), 66 deletions(-) diff --git a/drivers/gpu/drm/mcde/mcde_dsi.c b/drivers/gpu/drm/mcde/mcde_dsi.c index ae70f76bfb89..2314c8122992 100644 --- a/drivers/gpu/drm/mcde/mcde_dsi.c +++ b/drivers/gpu/drm/mcde/mcde_dsi.c @@ -208,15 +208,97 @@ static int mcde_dsi_host_detach(struct mipi_dsi_host *host, (type == MIPI_DSI_GENERIC_READ_REQUEST_2_PARAM) || \ (type == MIPI_DSI_DCS_READ)) +static int mcde_dsi_execute_transfer(struct mcde_dsi *d, + const struct mipi_dsi_msg *msg) +{ + const u32 loop_delay_us = 10; /* us */ + u32 loop_counter; + size_t txlen = msg->tx_len; + size_t rxlen = msg->rx_len; + int i; + u32 val; + int ret; + + writel(~0, d->regs + DSI_DIRECT_CMD_STS_CLR); + writel(~0, d->regs + DSI_CMD_MODE_STS_CLR); + /* Send command */ + writel(1, d->regs + DSI_DIRECT_CMD_SEND); + + loop_counter = 1000 * 1000 / loop_delay_us; + if (MCDE_DSI_HOST_IS_READ(msg->type)) { + /* Read command */ + while (!(readl(d->regs + DSI_DIRECT_CMD_STS) & + (DSI_DIRECT_CMD_STS_READ_COMPLETED | + DSI_DIRECT_CMD_STS_READ_COMPLETED_WITH_ERR)) + && --loop_counter) + usleep_range(loop_delay_us, (loop_delay_us * 3) / 2); + if (!loop_counter) { + dev_err(d->dev, "DSI read timeout!\n"); + /* Set exit code and retry */ + return -ETIME; + } + } else { + /* Writing only */ + while (!(readl(d->regs + DSI_DIRECT_CMD_STS) & + DSI_DIRECT_CMD_STS_WRITE_COMPLETED) + && --loop_counter) + usleep_range(loop_delay_us, (loop_delay_us * 3) / 2); + + if (!loop_counter) { + /* Set exit code and retry */ + dev_err(d->dev, "DSI write timeout!\n"); + return -ETIME; + } + } + + val = readl(d->regs + DSI_DIRECT_CMD_STS); + if (val & DSI_DIRECT_CMD_STS_READ_COMPLETED_WITH_ERR) { + dev_err(d->dev, "read completed with error\n"); + writel(1, d->regs + DSI_DIRECT_CMD_RD_INIT); + return -EIO; + } + if (val & DSI_DIRECT_CMD_STS_ACKNOWLEDGE_WITH_ERR_RECEIVED) { + val >>= DSI_DIRECT_CMD_STS_ACK_VAL_SHIFT; + dev_err(d->dev, "error during transmission: %04x\n", + val); + return -EIO; + } + + if (!MCDE_DSI_HOST_IS_READ(msg->type)) { + /* Return number of bytes written */ + ret = txlen; + } else { + /* OK this is a read command, get the response */ + u32 rdsz; + u32 rddat; + u8 *rx = msg->rx_buf; + + rdsz = readl(d->regs + DSI_DIRECT_CMD_RD_PROPERTY); + rdsz &= DSI_DIRECT_CMD_RD_PROPERTY_RD_SIZE_MASK; + rddat = readl(d->regs + DSI_DIRECT_CMD_RDDAT); + if (rdsz < rxlen) { + dev_err(d->dev, "read error, requested %zd got %d\n", + rxlen, rdsz); + return -EIO; + } + /* FIXME: read more than 4 bytes */ + for (i = 0; i < 4 && i < rxlen; i++) + rx[i] = (rddat >> (i * 8)) & 0xff; + ret = rdsz; + } + + /* Successful transmission */ + return ret; +} + static ssize_t mcde_dsi_host_transfer(struct mipi_dsi_host *host, const struct mipi_dsi_msg *msg) { struct mcde_dsi *d = host_to_mcde_dsi(host); - const u32 loop_delay_us = 10; /* us */ const u8 *tx = msg->tx_buf; - u32 loop_counter; size_t txlen = msg->tx_len; size_t rxlen = msg->rx_len; + unsigned int retries = 0; u32 val; int ret; int i; @@ -282,72 +364,16 @@ static ssize_t mcde_dsi_host_transfer(struct mipi_dsi_host *host, writel(val, d->regs + DSI_DIRECT_CMD_WRDAT3); } - writel(~0, d->regs + DSI_DIRECT_CMD_STS_CLR); - writel(~0, d->regs + DSI_CMD_MODE_STS_CLR); - /* Send command */ - writel(1, d->regs + DSI_DIRECT_CMD_SEND); - - loop_counter = 1000 * 1000 / loop_delay_us; - if (MCDE_DSI_HOST_IS_READ(msg->type)) { - /* Read command */ - while (!(readl(d->regs + DSI_DIRECT_CMD_STS) & - (DSI_DIRECT_CMD_STS_READ_COMPLETED | - DSI_DIRECT_CMD_STS_READ_COMPLETED_WITH_ERR)) - && --loop_counter) - usleep_range(loop_delay_us, (loop_delay_us * 3) / 2); - if (!loop_counter) { - dev_err(d->dev, "DSI read timeout!\n"); - return -ETIME; - } - } else { - /* Writing only */ - while (!(readl(d->regs + DSI_DIRECT_CMD_STS) & - DSI_DIRECT_CMD_STS_WRITE_COMPLETED) - && --loop_counter) - usleep_range(loop_delay_us, (loop_delay_us * 3) / 2); - - if (!loop_counter) { - dev_err(d->dev, "DSI write timeout!\n"); - return -ETIME; - } - } - - val = readl(d->regs + DSI_DIRECT_CMD_STS); - if (val & DSI_DIRECT_CMD_STS_READ_COMPLETED_WITH_ERR) { - dev_err(d->dev, "read completed with error\n"); - writel(1, d->regs + DSI_DIRECT_CMD_RD_INIT); - return -EIO; - } - if (val & DSI_DIRECT_CMD_STS_ACKNOWLEDGE_WITH_ERR_RECEIVED) { - val >>= DSI_DIRECT_CMD_STS_ACK_VAL_SHIFT; - dev_err(d->dev, "error during transmission: %04x\n", - val); - return -EIO; - } - - if (!MCDE_DSI_HOST_IS_READ(msg->type)) { - /* Return number of bytes written */ - ret = txlen; - } else { - /* OK this is a read command, get the response */ - u32 rdsz; - u32 rddat; - u8 *rx = msg->rx_buf; - - rdsz = readl(d->regs + DSI_DIRECT_CMD_RD_PROPERTY); - rdsz &= DSI_DIRECT_CMD_RD_PROPERTY_RD_SIZE_MASK; - rddat = readl(d->regs + DSI_DIRECT_CMD_RDDAT); - if (rdsz < rxlen) { - dev_err(d->dev, "read error, requested %zd got %d\n", - rxlen, rdsz); - return -EIO; - } - /* FIXME: read more than 4 bytes */ - for (i = 0; i < 4 && i < rxlen; i++) - rx[i] = (rddat >> (i * 8)) & 0xff; - ret = rdsz; + while (retries < 3) { + ret = mcde_dsi_execute_transfer(d, msg); + if (ret >= 0) + break; + retries++; } + if (ret < 0 && retries) + dev_err(d->dev, "gave up after %d retries\n", retries); + /* Clear any errors */ writel(~0, d->regs + DSI_DIRECT_CMD_STS_CLR); writel(~0, d->regs + DSI_CMD_MODE_STS_CLR);