Hi,
On 8/21/2019 11:57 PM, Chris Wilson wrote:
Quoting Animesh Manna (2019-08-21 07:32:25)
DSB can program large set of data through indexed register write
(opcode 0x9) in one shot. Will be using for bulk register programming
e.g. gamma lut programming, HDR meta data programming.
Cc: Shashank Sharma <shashank.sharma@xxxxxxxxx>
Cc: Imre Deak <imre.deak@xxxxxxxxx>
Cc: Jani Nikula <jani.nikula@xxxxxxxxx>
Cc: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
Signed-off-by: Animesh Manna <animesh.manna@xxxxxxxxx>
---
drivers/gpu/drm/i915/display/intel_dsb.c | 42 ++++++++++++++++++++++++
drivers/gpu/drm/i915/display/intel_dsb.h | 6 ++++
2 files changed, 48 insertions(+)
diff --git a/drivers/gpu/drm/i915/display/intel_dsb.c b/drivers/gpu/drm/i915/display/intel_dsb.c
index 8a9d082b1601..4fe8cac6246a 100644
--- a/drivers/gpu/drm/i915/display/intel_dsb.c
+++ b/drivers/gpu/drm/i915/display/intel_dsb.c
@@ -22,6 +22,7 @@
#define DSB_OPCODE_INDEXED_WRITE 0x9
#define DSB_OPCODE_POLL 0xA
#define DSB_BYTE_EN (0xf << 20)
+#define DSB_REG_VALUE_MASK 0xfffff
struct intel_dsb *
intel_dsb_get(struct intel_crtc *crtc)
@@ -79,6 +80,42 @@ intel_dsb_get(struct intel_crtc *crtc)
return dsb;
}
+static void intel_dsb_indexed_reg_write(struct intel_dsb *dsb, i915_reg_t reg,
+ u32 val)
+{
+ u32 *buf = dsb->cmd_buf;
+ u32 reg_val;
+
+ reg_val = buf[dsb->ins_start_offset + 1] & DSB_REG_VALUE_MASK;
Uncached read.
+ if (reg_val != i915_mmio_reg_offset(reg)) {
+ /* Every instruction should be 8 byte aligned. */
+ if (dsb->free_pos & 0x1)
+ dsb->free_pos++;
dsb->free_pos = ALIGN(dsb->free_pos, 2);
Ok.
+
+ /* Update the size. */
+ dsb->ins_start_offset = dsb->free_pos;
+ buf[dsb->free_pos++] = 1;
+
+ /* Update the opcode and reg. */
+ buf[dsb->free_pos++] = (DSB_OPCODE_INDEXED_WRITE <<
+ DSB_OPCODE_SHIFT) |
+ i915_mmio_reg_offset(reg);
+
+ /* Update the value. */
+ buf[dsb->free_pos++] = val;
+ } else {
+ /* Update the new value. */
+ buf[dsb->free_pos++] = val;
+
+ /* Update the size. */
+ buf[dsb->ins_start_offset]++;
Uncached read and write. So far this is working out to be _more_
expensive than mmio.
Understood your concern, currently tried to align with I915_WRITE() call
and coded accordingly.
If we can introduce a separate call for auto-increment register like below.
I915_WRITE_BULK(<reg-offset>, <buf-start-address>, <count>);
The implementation will be simpler and more optimized.
Good to know your feedback or any better way can be done.
Regards,
Animesh
-Chris
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