Re: [RFC PATCH v5 3/6] drm/tidss: Add support for AM625 DSS

From: Tomi Valkeinen
Date: Wed Oct 12 2022 - 08:09:28 EST


On 28/09/2022 20:52, Aradhya Bhatia wrote:
Add support for the DSS controller on TI's new AM625 SoC in the tidss
driver.

The first video port (VP0) in am625-dss can output OLDI signals through
2 OLDI TXes. A 3rd port has been added with "DISPC_VP_OLDI" bus type.

Signed-off-by: Aradhya Bhatia <a-bhatia1@xxxxxx>
---
drivers/gpu/drm/tidss/tidss_dispc.c | 61 ++++++++++++++++++++++++++++-
drivers/gpu/drm/tidss/tidss_dispc.h | 3 ++
drivers/gpu/drm/tidss/tidss_drv.c | 1 +
3 files changed, 64 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/tidss/tidss_dispc.c b/drivers/gpu/drm/tidss/tidss_dispc.c
index dd3c6a606ae2..34f0da4bb3e3 100644
--- a/drivers/gpu/drm/tidss/tidss_dispc.c
+++ b/drivers/gpu/drm/tidss/tidss_dispc.c
@@ -93,6 +93,7 @@ const struct dispc_features dispc_k2g_feats = {
.common_regs = tidss_k2g_common_regs,
.num_vps = 1,
+ .num_max_ports = 1,
.vp_name = { "vp1" },
.ovr_name = { "ovr1" },
.vpclk_name = { "vp1" },
@@ -168,6 +169,7 @@ const struct dispc_features dispc_am65x_feats = {
.common_regs = tidss_am65x_common_regs,
.num_vps = 2,
+ .num_max_ports = 2,
.vp_name = { "vp1", "vp2" },
.ovr_name = { "ovr1", "ovr2" },
.vpclk_name = { "vp1", "vp2" },
@@ -257,6 +259,7 @@ const struct dispc_features dispc_j721e_feats = {
.common_regs = tidss_j721e_common_regs,
.num_vps = 4,
+ .num_max_ports = 4,
.vp_name = { "vp1", "vp2", "vp3", "vp4" },
.ovr_name = { "ovr1", "ovr2", "ovr3", "ovr4" },
.vpclk_name = { "vp1", "vp2", "vp3", "vp4" },
@@ -275,6 +278,57 @@ const struct dispc_features dispc_j721e_feats = {
.vid_order = { 1, 3, 0, 2 },
};
+const struct dispc_features dispc_am625_feats = {
+ .max_pclk_khz = {
+ [DISPC_VP_DPI] = 165000,
+ [DISPC_VP_OLDI] = 165000,
+ },
+
+ .scaling = {
+ .in_width_max_5tap_rgb = 1280,
+ .in_width_max_3tap_rgb = 2560,
+ .in_width_max_5tap_yuv = 2560,
+ .in_width_max_3tap_yuv = 4096,
+ .upscale_limit = 16,
+ .downscale_limit_5tap = 4,
+ .downscale_limit_3tap = 2,
+ /*
+ * The max supported pixel inc value is 255. The value
+ * of pixel inc is calculated like this: 1+(xinc-1)*bpp.
+ * The maximum bpp of all formats supported by the HW
+ * is 8. So the maximum supported xinc value is 32,
+ * because 1+(32-1)*8 < 255 < 1+(33-1)*4.
+ */
+ .xinc_max = 32,
+ },
+
+ .subrev = DISPC_AM625,
+
+ .common = "common",
+ .common_regs = tidss_am65x_common_regs,
+
+ .num_vps = 2,
+ /* note: the 3rd port is not representative of a 3rd pipeline */
+ .num_max_ports = 3,
+ .vp_name = { "vp1", "vp2" },
+ .ovr_name = { "ovr1", "ovr2" },
+ .vpclk_name = { "vp1", "vp2" },
+ .vp_bus_type = { DISPC_VP_OLDI, DISPC_VP_DPI, DISPC_VP_OLDI },

Here, for example, we have an issue with the VP vs port. vp_bus_type is of size TIDSS_MAX_PORTS (VPs), but you're using it for output ports. If we did not have J7, which has 4 VPs, we'd have an overflow bug here.

The meaning of vp_sub_type also becomes a bit unclear. I guess it's rather "output_port_bus_type"?

Tomi