| Message ID | 20170129132444.25251-25-john@metanate.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Sun, Jan 29, 2017 at 01:24:44PM +0000, John Keeping wrote: > I haven't found any method for getting the length of a response, so this > just uses the requested rx_len > > Signed-off-by: John Keeping <john@metanate.com> > --- > v3: > - Fix checkpatch warnings > Unchanged in v2 > > drivers/gpu/drm/rockchip/dw-mipi-dsi.c | 56 ++++++++++++++++++++++++++++++++++ > 1 file changed, 56 insertions(+) > > diff --git a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c > index cf3ca6b0cbdb..cc58ada75425 100644 > --- a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c > +++ b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c > @@ -678,6 +678,56 @@ static int dw_mipi_dsi_dcs_long_write(struct dw_mipi_dsi *dsi, > return dw_mipi_dsi_gen_pkt_hdr_write(dsi, hdr_val); > } > > +static int dw_mipi_dsi_dcs_read(struct dw_mipi_dsi *dsi, > + const struct mipi_dsi_msg *msg) > +{ > + const u8 *tx_buf = msg->tx_buf; > + u8 *rx_buf = msg->rx_buf; > + size_t i; > + int ret, val; > + > + dsi_write(dsi, DSI_PCKHDL_CFG, EN_CRC_RX | EN_ECC_RX | EN_BTA); > + dsi_write(dsi, DSI_GEN_HDR, > + GEN_HDATA(tx_buf[0]) | GEN_HTYPE(msg->type)); > + > + ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS, > + val, !(val & GEN_RD_CMD_BUSY), 1000, > + CMD_PKT_STATUS_TIMEOUT_US); > + if (ret < 0) { > + dev_err(dsi->dev, "failed to read command response\n"); > + return ret; > + } > + > + for (i = 0; i < msg->rx_len;) { > + u32 pld = dsi_read(dsi, DSI_GEN_PLD_DATA); > + > + while (i < msg->rx_len) { > + rx_buf[i] = pld & 0xff; > + pld >>= 8; > + i++; > + } > + } AFAICT, the outer for loop just initializes i and ensures msg->rx_len is non-zero? I think the following would be easier to read (and safe against the case where msg->rx_len > sizeof(pld) (even though this shouldn't happen according to DCS spec)). if (msg->rx_len > 0) { u32 pld = dsi_read(dsi, DSI_GEN_PLD_DATA); memcpy(rx_buf, &pld, MIN(msg->rx_len, sizeof(pld)); } > + > + return msg->rx_len; > +} > + > +static int dw_mipi_dsi_set_max_return_packet_size(struct dw_mipi_dsi *dsi, > + size_t len) > +{ > + u8 val[] = { len & 0xff, (len >> 8) & 0xff }; > + struct mipi_dsi_msg msg = { > + .channel = dsi->channel, > + .type = MIPI_DSI_SET_MAXIMUM_RETURN_PACKET_SIZE, > + .tx_buf = val, > + .tx_len = 2, > + }; > + > + if (len > 0xffff) > + return -EINVAL; > + > + return dw_mipi_dsi_dcs_short_write(dsi, &msg); > +} > + > static ssize_t dw_mipi_dsi_host_transfer(struct mipi_dsi_host *host, > const struct mipi_dsi_msg *msg) > { > @@ -695,6 +745,12 @@ static ssize_t dw_mipi_dsi_host_transfer(struct mipi_dsi_host *host, > case MIPI_DSI_DCS_LONG_WRITE: > ret = dw_mipi_dsi_dcs_long_write(dsi, msg); > break; > + case MIPI_DSI_DCS_READ: > + ret = dw_mipi_dsi_set_max_return_packet_size(dsi, msg->rx_len); > + if (ret < 0) > + return ret; > + ret = dw_mipi_dsi_dcs_read(dsi, msg); > + break; > default: > dev_err(dsi->dev, "unsupported message type 0x%02x\n", > msg->type); > -- > 2.11.0.197.gb556de5.dirty > > _______________________________________________ > dri-devel mailing list > dri-devel@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/dri-devel
On Mon, 30 Jan 2017 10:26:11 -0500, Sean Paul wrote: > On Sun, Jan 29, 2017 at 01:24:44PM +0000, John Keeping wrote: > > I haven't found any method for getting the length of a response, so this > > just uses the requested rx_len > > > > Signed-off-by: John Keeping <john@metanate.com> > > --- > > v3: > > - Fix checkpatch warnings > > Unchanged in v2 > > > > drivers/gpu/drm/rockchip/dw-mipi-dsi.c | 56 ++++++++++++++++++++++++++++++++++ > > 1 file changed, 56 insertions(+) > > > > diff --git a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c > > index cf3ca6b0cbdb..cc58ada75425 100644 > > --- a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c > > +++ b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c > > @@ -678,6 +678,56 @@ static int dw_mipi_dsi_dcs_long_write(struct dw_mipi_dsi *dsi, > > return dw_mipi_dsi_gen_pkt_hdr_write(dsi, hdr_val); > > } > > > > +static int dw_mipi_dsi_dcs_read(struct dw_mipi_dsi *dsi, > > + const struct mipi_dsi_msg *msg) > > +{ > > + const u8 *tx_buf = msg->tx_buf; > > + u8 *rx_buf = msg->rx_buf; > > + size_t i; > > + int ret, val; > > + > > + dsi_write(dsi, DSI_PCKHDL_CFG, EN_CRC_RX | EN_ECC_RX | EN_BTA); > > + dsi_write(dsi, DSI_GEN_HDR, > > + GEN_HDATA(tx_buf[0]) | GEN_HTYPE(msg->type)); > > + > > + ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS, > > + val, !(val & GEN_RD_CMD_BUSY), 1000, > > + CMD_PKT_STATUS_TIMEOUT_US); > > + if (ret < 0) { > > + dev_err(dsi->dev, "failed to read command response\n"); > > + return ret; > > + } > > + > > + for (i = 0; i < msg->rx_len;) { > > + u32 pld = dsi_read(dsi, DSI_GEN_PLD_DATA); > > + > > + while (i < msg->rx_len) { > > + rx_buf[i] = pld & 0xff; > > + pld >>= 8; > > + i++; > > + } > > + } > > AFAICT, the outer for loop just initializes i and ensures msg->rx_len is > non-zero? > > I think the following would be easier to read (and safe against the case where > msg->rx_len > sizeof(pld) (even though this shouldn't happen according to DCS > spec)). > > if (msg->rx_len > 0) { > u32 pld = dsi_read(dsi, DSI_GEN_PLD_DATA); > memcpy(rx_buf, &pld, MIN(msg->rx_len, sizeof(pld)); > } I think the intent was to handle rx_len > 4, but the patch is obvously completely broken regarding that. As far as I can tell, rx_len is limited by the maximum return packet size which can be any value up to the maximum size of a long packet, so we may need to read from the FIFO multiple times. The loop should be something like this: for (i = 0; i < msg->rx_len;) { u32 pld = dsi_read(dsi, DSI_GEN_PLD_DATA); int j; for (j = 0; j < 4 && i < msg->rx_len; i++, j++) { rx_buf[i] = pld & 0xff; pld >>= 8; } } I have successfully read 5 bytes from a DSI display using this code, but I'm tempted to just drop this patch since I only used it for debugging while bringing up a new panel.
On Mon, Jan 30, 2017 at 06:14:27PM +0000, John Keeping wrote: > On Mon, 30 Jan 2017 10:26:11 -0500, Sean Paul wrote: > > > On Sun, Jan 29, 2017 at 01:24:44PM +0000, John Keeping wrote: > > > I haven't found any method for getting the length of a response, so this > > > just uses the requested rx_len > > > > > > Signed-off-by: John Keeping <john@metanate.com> > > > --- > > > v3: > > > - Fix checkpatch warnings > > > Unchanged in v2 > > > > > > drivers/gpu/drm/rockchip/dw-mipi-dsi.c | 56 ++++++++++++++++++++++++++++++++++ > > > 1 file changed, 56 insertions(+) > > > > > > diff --git a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c > > > index cf3ca6b0cbdb..cc58ada75425 100644 > > > --- a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c > > > +++ b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c > > > @@ -678,6 +678,56 @@ static int dw_mipi_dsi_dcs_long_write(struct dw_mipi_dsi *dsi, > > > return dw_mipi_dsi_gen_pkt_hdr_write(dsi, hdr_val); > > > } > > > > > > +static int dw_mipi_dsi_dcs_read(struct dw_mipi_dsi *dsi, > > > + const struct mipi_dsi_msg *msg) > > > +{ > > > + const u8 *tx_buf = msg->tx_buf; > > > + u8 *rx_buf = msg->rx_buf; > > > + size_t i; > > > + int ret, val; > > > + > > > + dsi_write(dsi, DSI_PCKHDL_CFG, EN_CRC_RX | EN_ECC_RX | EN_BTA); > > > + dsi_write(dsi, DSI_GEN_HDR, > > > + GEN_HDATA(tx_buf[0]) | GEN_HTYPE(msg->type)); > > > + > > > + ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS, > > > + val, !(val & GEN_RD_CMD_BUSY), 1000, > > > + CMD_PKT_STATUS_TIMEOUT_US); > > > + if (ret < 0) { > > > + dev_err(dsi->dev, "failed to read command response\n"); > > > + return ret; > > > + } > > > + > > > + for (i = 0; i < msg->rx_len;) { > > > + u32 pld = dsi_read(dsi, DSI_GEN_PLD_DATA); > > > + > > > + while (i < msg->rx_len) { > > > + rx_buf[i] = pld & 0xff; > > > + pld >>= 8; > > > + i++; > > > + } > > > + } > > > > AFAICT, the outer for loop just initializes i and ensures msg->rx_len is > > non-zero? > > > > I think the following would be easier to read (and safe against the case where > > msg->rx_len > sizeof(pld) (even though this shouldn't happen according to DCS > > spec)). > > > > if (msg->rx_len > 0) { > > u32 pld = dsi_read(dsi, DSI_GEN_PLD_DATA); > > memcpy(rx_buf, &pld, MIN(msg->rx_len, sizeof(pld)); > > } > > I think the intent was to handle rx_len > 4, but the patch is obvously > completely broken regarding that. As far as I can tell, rx_len is > limited by the maximum return packet size which can be any value up to > the maximum size of a long packet, so we may need to read from the FIFO > multiple times. > > The loop should be something like this: > > for (i = 0; i < msg->rx_len;) { > u32 pld = dsi_read(dsi, DSI_GEN_PLD_DATA); > int j; > > for (j = 0; j < 4 && i < msg->rx_len; i++, j++) { > rx_buf[i] = pld & 0xff; > pld >>= 8; > } > } Short packets should never exceed 32 bits, so I don't think you need to add the nested loop. Sean > > I have successfully read 5 bytes from a DSI display using this code, but > I'm tempted to just drop this patch since I only used it for debugging > while bringing up a new panel. > _______________________________________________ > dri-devel mailing list > dri-devel@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/dri-devel
On Mon, 30 Jan 2017 15:16:09 -0500, Sean Paul wrote: > On Mon, Jan 30, 2017 at 06:14:27PM +0000, John Keeping wrote: > > On Mon, 30 Jan 2017 10:26:11 -0500, Sean Paul wrote: > > > > > On Sun, Jan 29, 2017 at 01:24:44PM +0000, John Keeping wrote: > > > > I haven't found any method for getting the length of a response, so this > > > > just uses the requested rx_len > > > > > > > > Signed-off-by: John Keeping <john@metanate.com> > > > > --- > > > > v3: > > > > - Fix checkpatch warnings > > > > Unchanged in v2 > > > > > > > > drivers/gpu/drm/rockchip/dw-mipi-dsi.c | 56 ++++++++++++++++++++++++++++++++++ > > > > 1 file changed, 56 insertions(+) > > > > > > > > diff --git a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c > > > > index cf3ca6b0cbdb..cc58ada75425 100644 > > > > --- a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c > > > > +++ b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c > > > > @@ -678,6 +678,56 @@ static int dw_mipi_dsi_dcs_long_write(struct dw_mipi_dsi *dsi, > > > > return dw_mipi_dsi_gen_pkt_hdr_write(dsi, hdr_val); > > > > } > > > > > > > > +static int dw_mipi_dsi_dcs_read(struct dw_mipi_dsi *dsi, > > > > + const struct mipi_dsi_msg *msg) > > > > +{ > > > > + const u8 *tx_buf = msg->tx_buf; > > > > + u8 *rx_buf = msg->rx_buf; > > > > + size_t i; > > > > + int ret, val; > > > > + > > > > + dsi_write(dsi, DSI_PCKHDL_CFG, EN_CRC_RX | EN_ECC_RX | EN_BTA); > > > > + dsi_write(dsi, DSI_GEN_HDR, > > > > + GEN_HDATA(tx_buf[0]) | GEN_HTYPE(msg->type)); > > > > + > > > > + ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS, > > > > + val, !(val & GEN_RD_CMD_BUSY), 1000, > > > > + CMD_PKT_STATUS_TIMEOUT_US); > > > > + if (ret < 0) { > > > > + dev_err(dsi->dev, "failed to read command response\n"); > > > > + return ret; > > > > + } > > > > + > > > > + for (i = 0; i < msg->rx_len;) { > > > > + u32 pld = dsi_read(dsi, DSI_GEN_PLD_DATA); > > > > + > > > > + while (i < msg->rx_len) { > > > > + rx_buf[i] = pld & 0xff; > > > > + pld >>= 8; > > > > + i++; > > > > + } > > > > + } > > > > > > AFAICT, the outer for loop just initializes i and ensures msg->rx_len is > > > non-zero? > > > > > > I think the following would be easier to read (and safe against the case where > > > msg->rx_len > sizeof(pld) (even though this shouldn't happen according to DCS > > > spec)). > > > > > > if (msg->rx_len > 0) { > > > u32 pld = dsi_read(dsi, DSI_GEN_PLD_DATA); > > > memcpy(rx_buf, &pld, MIN(msg->rx_len, sizeof(pld)); > > > } > > > > I think the intent was to handle rx_len > 4, but the patch is obvously > > completely broken regarding that. As far as I can tell, rx_len is > > limited by the maximum return packet size which can be any value up to > > the maximum size of a long packet, so we may need to read from the FIFO > > multiple times. > > > > The loop should be something like this: > > > > for (i = 0; i < msg->rx_len;) { > > u32 pld = dsi_read(dsi, DSI_GEN_PLD_DATA); > > int j; > > > > for (j = 0; j < 4 && i < msg->rx_len; i++, j++) { > > rx_buf[i] = pld & 0xff; > > pld >>= 8; > > } > > } > > Short packets should never exceed 32 bits, so I don't think you need to add the > nested loop. The read response is not restricted to a short packet. I have a panel that documents a read request that returns up to 64KiB, admittedly with a continuation command and the panels I have seem to only be programmed to return 5 bytes of meaningful data, but they do return all of those bytes in a single read response.
On Tue, Jan 31, 2017 at 12:41:47PM +0000, John Keeping wrote: > On Mon, 30 Jan 2017 15:16:09 -0500, Sean Paul wrote: > > > On Mon, Jan 30, 2017 at 06:14:27PM +0000, John Keeping wrote: > > > On Mon, 30 Jan 2017 10:26:11 -0500, Sean Paul wrote: > > > > > > > On Sun, Jan 29, 2017 at 01:24:44PM +0000, John Keeping wrote: > > > > > I haven't found any method for getting the length of a response, so this > > > > > just uses the requested rx_len > > > > > > > > > > Signed-off-by: John Keeping <john@metanate.com> > > > > > --- > > > > > v3: > > > > > - Fix checkpatch warnings > > > > > Unchanged in v2 > > > > > > > > > > drivers/gpu/drm/rockchip/dw-mipi-dsi.c | 56 ++++++++++++++++++++++++++++++++++ > > > > > 1 file changed, 56 insertions(+) > > > > > > > > > > diff --git a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c > > > > > index cf3ca6b0cbdb..cc58ada75425 100644 > > > > > --- a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c > > > > > +++ b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c > > > > > @@ -678,6 +678,56 @@ static int dw_mipi_dsi_dcs_long_write(struct dw_mipi_dsi *dsi, > > > > > return dw_mipi_dsi_gen_pkt_hdr_write(dsi, hdr_val); > > > > > } > > > > > > > > > > +static int dw_mipi_dsi_dcs_read(struct dw_mipi_dsi *dsi, > > > > > + const struct mipi_dsi_msg *msg) > > > > > +{ > > > > > + const u8 *tx_buf = msg->tx_buf; > > > > > + u8 *rx_buf = msg->rx_buf; > > > > > + size_t i; > > > > > + int ret, val; > > > > > + > > > > > + dsi_write(dsi, DSI_PCKHDL_CFG, EN_CRC_RX | EN_ECC_RX | EN_BTA); > > > > > + dsi_write(dsi, DSI_GEN_HDR, > > > > > + GEN_HDATA(tx_buf[0]) | GEN_HTYPE(msg->type)); > > > > > + > > > > > + ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS, > > > > > + val, !(val & GEN_RD_CMD_BUSY), 1000, > > > > > + CMD_PKT_STATUS_TIMEOUT_US); > > > > > + if (ret < 0) { > > > > > + dev_err(dsi->dev, "failed to read command response\n"); > > > > > + return ret; > > > > > + } > > > > > + > > > > > + for (i = 0; i < msg->rx_len;) { > > > > > + u32 pld = dsi_read(dsi, DSI_GEN_PLD_DATA); > > > > > + > > > > > + while (i < msg->rx_len) { > > > > > + rx_buf[i] = pld & 0xff; > > > > > + pld >>= 8; > > > > > + i++; > > > > > + } > > > > > + } > > > > > > > > AFAICT, the outer for loop just initializes i and ensures msg->rx_len is > > > > non-zero? > > > > > > > > I think the following would be easier to read (and safe against the case where > > > > msg->rx_len > sizeof(pld) (even though this shouldn't happen according to DCS > > > > spec)). > > > > > > > > if (msg->rx_len > 0) { > > > > u32 pld = dsi_read(dsi, DSI_GEN_PLD_DATA); > > > > memcpy(rx_buf, &pld, MIN(msg->rx_len, sizeof(pld)); > > > > } > > > > > > I think the intent was to handle rx_len > 4, but the patch is obvously > > > completely broken regarding that. As far as I can tell, rx_len is > > > limited by the maximum return packet size which can be any value up to > > > the maximum size of a long packet, so we may need to read from the FIFO > > > multiple times. > > > > > > The loop should be something like this: > > > > > > for (i = 0; i < msg->rx_len;) { > > > u32 pld = dsi_read(dsi, DSI_GEN_PLD_DATA); > > > int j; > > > > > > for (j = 0; j < 4 && i < msg->rx_len; i++, j++) { > > > rx_buf[i] = pld & 0xff; > > > pld >>= 8; > > > } > > > } > > > > Short packets should never exceed 32 bits, so I don't think you need to add the > > nested loop. > > The read response is not restricted to a short packet. I have a panel > that documents a read request that returns up to 64KiB, admittedly with > a continuation command and the panels I have seem to only be programmed > to return 5 bytes of meaningful data, but they do return all of those > bytes in a single read response. Ah, apologies for the misunderstanding. In that case, I think you can get away with replacing the inner loop in your snippet with a memcpy and call it a day. Sean > _______________________________________________ > dri-devel mailing list > dri-devel@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/dri-devel
diff --git a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c index cf3ca6b0cbdb..cc58ada75425 100644 --- a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c +++ b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c @@ -678,6 +678,56 @@ static int dw_mipi_dsi_dcs_long_write(struct dw_mipi_dsi *dsi, return dw_mipi_dsi_gen_pkt_hdr_write(dsi, hdr_val); } +static int dw_mipi_dsi_dcs_read(struct dw_mipi_dsi *dsi, + const struct mipi_dsi_msg *msg) +{ + const u8 *tx_buf = msg->tx_buf; + u8 *rx_buf = msg->rx_buf; + size_t i; + int ret, val; + + dsi_write(dsi, DSI_PCKHDL_CFG, EN_CRC_RX | EN_ECC_RX | EN_BTA); + dsi_write(dsi, DSI_GEN_HDR, + GEN_HDATA(tx_buf[0]) | GEN_HTYPE(msg->type)); + + ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS, + val, !(val & GEN_RD_CMD_BUSY), 1000, + CMD_PKT_STATUS_TIMEOUT_US); + if (ret < 0) { + dev_err(dsi->dev, "failed to read command response\n"); + return ret; + } + + for (i = 0; i < msg->rx_len;) { + u32 pld = dsi_read(dsi, DSI_GEN_PLD_DATA); + + while (i < msg->rx_len) { + rx_buf[i] = pld & 0xff; + pld >>= 8; + i++; + } + } + + return msg->rx_len; +} + +static int dw_mipi_dsi_set_max_return_packet_size(struct dw_mipi_dsi *dsi, + size_t len) +{ + u8 val[] = { len & 0xff, (len >> 8) & 0xff }; + struct mipi_dsi_msg msg = { + .channel = dsi->channel, + .type = MIPI_DSI_SET_MAXIMUM_RETURN_PACKET_SIZE, + .tx_buf = val, + .tx_len = 2, + }; + + if (len > 0xffff) + return -EINVAL; + + return dw_mipi_dsi_dcs_short_write(dsi, &msg); +} + static ssize_t dw_mipi_dsi_host_transfer(struct mipi_dsi_host *host, const struct mipi_dsi_msg *msg) { @@ -695,6 +745,12 @@ static ssize_t dw_mipi_dsi_host_transfer(struct mipi_dsi_host *host, case MIPI_DSI_DCS_LONG_WRITE: ret = dw_mipi_dsi_dcs_long_write(dsi, msg); break; + case MIPI_DSI_DCS_READ: + ret = dw_mipi_dsi_set_max_return_packet_size(dsi, msg->rx_len); + if (ret < 0) + return ret; + ret = dw_mipi_dsi_dcs_read(dsi, msg); + break; default: dev_err(dsi->dev, "unsupported message type 0x%02x\n", msg->type);
I haven't found any method for getting the length of a response, so this just uses the requested rx_len Signed-off-by: John Keeping <john@metanate.com> --- v3: - Fix checkpatch warnings Unchanged in v2 drivers/gpu/drm/rockchip/dw-mipi-dsi.c | 56 ++++++++++++++++++++++++++++++++++ 1 file changed, 56 insertions(+)