[PATCH] drm/bridge/synopsys: dsi: use common mipi_dsi_create_packet()

From: Brian Norris
Date: Fri Jan 05 2018 - 19:38:30 EST


This takes care of 2 TODOs in this driver, by using the common DSI
packet-marshalling code instead of our custom short/long write code.
This both saves us some duplicated code and gets us free support for
command types that weren't already part of our switch block (e.g.,
MIPI_DSI_GENERIC_LONG_WRITE).

The code logic stays mostly intact, except that it becomes unnecessary
to split the short/long write functions, and we have to copy data a bit
more.

Along the way, I noticed that loop bounds were a little odd:

while (DIV_ROUND_UP(len, pld_data_bytes))

This really was just supposed to be 'len != 0', so I made that more
clear.

Tested on RK3399 with some pending refactoring patches by Nickey Yang,
to make the Rockchip DSI driver wrap this common driver.

Signed-off-by: Brian Norris <briannorris@xxxxxxxxxxxx>
---
Could use an extra look from folks. This looks like the correct trivial
transformation, but I'm not that familiar with DSI.

drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c | 78 ++++++---------------------
1 file changed, 16 insertions(+), 62 deletions(-)

diff --git a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
index d9cca4fd66ec..2fed20e44dfe 100644
--- a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
+++ b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
@@ -136,10 +136,6 @@
GEN_SW_0P_TX_LP)

#define DSI_GEN_HDR 0x6c
-/* TODO These 2 defines will be reworked thanks to mipi_dsi_create_packet() */
-#define GEN_HDATA(data) (((data) & 0xffff) << 8)
-#define GEN_HTYPE(type) (((type) & 0xff) << 0)
-
#define DSI_GEN_PLD_DATA 0x70

#define DSI_CMD_PKT_STATUS 0x74
@@ -359,44 +355,15 @@ static int dw_mipi_dsi_gen_pkt_hdr_write(struct dw_mipi_dsi *dsi, u32 hdr_val)
return 0;
}

-static int dw_mipi_dsi_dcs_short_write(struct dw_mipi_dsi *dsi,
- const struct mipi_dsi_msg *msg)
-{
- const u8 *tx_buf = msg->tx_buf;
- u16 data = 0;
- u32 val;
-
- if (msg->tx_len > 0)
- data |= tx_buf[0];
- if (msg->tx_len > 1)
- data |= tx_buf[1] << 8;
-
- if (msg->tx_len > 2) {
- dev_err(dsi->dev, "too long tx buf length %zu for short write\n",
- msg->tx_len);
- return -EINVAL;
- }
-
- val = GEN_HDATA(data) | GEN_HTYPE(msg->type);
- return dw_mipi_dsi_gen_pkt_hdr_write(dsi, val);
-}
-
-static int dw_mipi_dsi_dcs_long_write(struct dw_mipi_dsi *dsi,
- const struct mipi_dsi_msg *msg)
+static int dw_mipi_dsi_dcs_write(struct dw_mipi_dsi *dsi,
+ const struct mipi_dsi_packet *packet)
{
- const u8 *tx_buf = msg->tx_buf;
- int len = msg->tx_len, pld_data_bytes = sizeof(u32), ret;
- u32 hdr_val = GEN_HDATA(msg->tx_len) | GEN_HTYPE(msg->type);
+ const u8 *tx_buf = packet->payload;
+ int len = packet->payload_length, pld_data_bytes = sizeof(u32), ret;
u32 remainder;
u32 val;

- if (msg->tx_len < 3) {
- dev_err(dsi->dev, "wrong tx buf length %zu for long write\n",
- msg->tx_len);
- return -EINVAL;
- }
-
- while (DIV_ROUND_UP(len, pld_data_bytes)) {
+ while (len) {
if (len < pld_data_bytes) {
remainder = 0;
memcpy(&remainder, tx_buf, len);
@@ -419,40 +386,27 @@ static int dw_mipi_dsi_dcs_long_write(struct dw_mipi_dsi *dsi,
}
}

- return dw_mipi_dsi_gen_pkt_hdr_write(dsi, hdr_val);
+ remainder = 0;
+ memcpy(&remainder, packet->header, sizeof(packet->header));
+ return dw_mipi_dsi_gen_pkt_hdr_write(dsi, remainder);
}

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;

- /*
- * TODO dw drv improvements
- * use mipi_dsi_create_packet() instead of all following
- * functions and code (no switch cases, no
- * dw_mipi_dsi_dcs_short_write(), only the loop in long_write...)
- * and use packet.header...
- */
- dw_mipi_message_config(dsi, msg);
-
- switch (msg->type) {
- case MIPI_DSI_DCS_SHORT_WRITE:
- case MIPI_DSI_DCS_SHORT_WRITE_PARAM:
- case MIPI_DSI_SET_MAXIMUM_RETURN_PACKET_SIZE:
- ret = dw_mipi_dsi_dcs_short_write(dsi, msg);
- break;
- case MIPI_DSI_DCS_LONG_WRITE:
- ret = dw_mipi_dsi_dcs_long_write(dsi, msg);
- break;
- default:
- dev_err(dsi->dev, "unsupported message type 0x%02x\n",
- msg->type);
- ret = -EINVAL;
+ ret = mipi_dsi_create_packet(&packet, msg);
+ if (ret) {
+ dev_err(dsi->dev, "failed to create packet: %d\n", ret);
+ return ret;
}

- return ret;
+ dw_mipi_message_config(dsi, msg);
+
+ return dw_mipi_dsi_dcs_write(dsi, &packet);
}

static const struct mipi_dsi_host_ops dw_mipi_dsi_host_ops = {
--
2.16.0.rc0.223.g4a4ac83678-goog