From: Philippe Cornu Date: Sun, 4 Feb 2018 22:31:04 +0100 Subject: drm/bridge/synopsys: dsi: Add read feature Git-commit: a009c53e8dead27f4917b389c3d7ea528dcb67fb Patch-mainline: v4.17-rc1 References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166 This patch adds the DCS/GENERIC DSI read feature. Signed-off-by: Philippe Cornu Reviewed-by: Andrzej Hajda Reviewed-by: Brian Norris Signed-off-by: Andrzej Hajda Link: https://patchwork.freedesktop.org/patch/msgid/20180204213104.17834-1-philippe.cornu@st.com Acked-by: Petr Tesarik --- drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c | 58 ++++++++++++++++++++------ 1 file changed, 45 insertions(+), 13 deletions(-) --- a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c +++ b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c @@ -391,18 +391,46 @@ static int dw_mipi_dsi_write(struct dw_m return dw_mipi_dsi_gen_pkt_hdr_write(dsi, le32_to_cpu(word)); } +static int dw_mipi_dsi_read(struct dw_mipi_dsi *dsi, + const struct mipi_dsi_msg *msg) +{ + int i, j, ret, len = msg->rx_len; + u8 *buf = msg->rx_buf; + u32 val; + + /* Wait end of the read operation */ + ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS, + val, !(val & GEN_RD_CMD_BUSY), + 1000, CMD_PKT_STATUS_TIMEOUT_US); + if (ret) { + dev_err(dsi->dev, "Timeout during read operation\n"); + return ret; + } + + for (i = 0; i < len; i += 4) { + /* Read fifo must not be empty before all bytes are read */ + ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS, + val, !(val & GEN_PLD_R_EMPTY), + 1000, CMD_PKT_STATUS_TIMEOUT_US); + if (ret) { + dev_err(dsi->dev, "Read payload FIFO is empty\n"); + return ret; + } + + val = dsi_read(dsi, DSI_GEN_PLD_DATA); + for (j = 0; j < 4 && j + i < len; j++) + buf[i + j] = val >> (8 * j); + } + + return ret; +} + static ssize_t dw_mipi_dsi_host_transfer(struct mipi_dsi_host *host, const struct mipi_dsi_msg *msg) { struct dw_mipi_dsi *dsi = host_to_dsi(host); struct mipi_dsi_packet packet; - int ret; - - if (msg->rx_buf || msg->rx_len) { - /* TODO dw drv improvements: implement read feature */ - dev_warn(dsi->dev, "read operations not yet implemented\n"); - return -EINVAL; - } + int ret, nb_bytes; ret = mipi_dsi_create_packet(&packet, msg); if (ret) { @@ -416,12 +444,16 @@ static ssize_t dw_mipi_dsi_host_transfer if (ret) return ret; - /* - * TODO Only transmitted size is returned as actual driver does - * not support dcs/generic reads. Please update return value when - * delivering the read feature. - */ - return packet.size; + if (msg->rx_buf && msg->rx_len) { + ret = dw_mipi_dsi_read(dsi, msg); + if (ret) + return ret; + nb_bytes = msg->rx_len; + } else { + nb_bytes = packet.size; + } + + return nb_bytes; } static const struct mipi_dsi_host_ops dw_mipi_dsi_host_ops = {