[PATCH 5.4 05/16] drm/etnaviv: fix TS cache flushing on GPUs with BLT engine

Greg Kroah-Hartman
2020-09-04T13:40:42Z

From: Lucas Stach <l.stach@pengutronix.de>

commit f232d9ec029ce3e2543b05213e2979e01e503408 upstream.

As seen in the Vivante kernel driver, most GPUs with the BLT engine have
a broken TS cache flush. The workaround is to temporarily set the BLT
command to CLEAR_IMAGE, without actually executing the clear. Apparently
this state change is enough to trigger the required TS cache flush. As
the BLT engine is completely asychronous, we also need a few more stall
states to synchronize the flush with the frontend.

Root-caused-by: Jonathan Marek <jonathan@marek.ca>
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Cc: Walter Lozano <walter.lozano@collabora.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/gpu/drm/etnaviv/etnaviv_buffer.c | 60 ++++++++++++++++++++++++++++---
drivers/gpu/drm/etnaviv/state_blt.xml.h | 2 +
2 files changed, 57 insertions(+), 5 deletions(-)

--- a/drivers/gpu/drm/etnaviv/etnaviv_buffer.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_buffer.c
@@ -12,6 +12,7 @@

#include "common.xml.h"
#include "state.xml.h"
+#include "state_blt.xml.h"
#include "state_hi.xml.h"
#include "state_3d.xml.h"
#include "cmdstream.xml.h"
@@ -233,6 +234,8 @@ void etnaviv_buffer_end(struct etnaviv_g
struct etnaviv_cmdbuf *buffer = &gpu->buffer;
unsigned int waitlink_offset = buffer->user_size - 16;
u32 link_target, flush = 0;
+ bool has_blt = !!(gpu->identity.minor_features5 &
+ chipMinorFeatures5_BLT_ENGINE);

lockdep_assert_held(&gpu->lock);

@@ -248,16 +251,38 @@ void etnaviv_buffer_end(struct etnaviv_g
if (flush) {
unsigned int dwords = 7;

+ if (has_blt)
+ dwords += 10;
+
link_target = etnaviv_buffer_reserve(gpu, buffer, dwords);

CMD_SEM(buffer, SYNC_RECIPIENT_FE, SYNC_RECIPIENT_PE);
CMD_STALL(buffer, SYNC_RECIPIENT_FE, SYNC_RECIPIENT_PE);
+ if (has_blt) {
+ CMD_LOAD_STATE(buffer, VIVS_BLT_ENABLE, 0x1);
+ CMD_SEM(buffer, SYNC_RECIPIENT_FE, SYNC_RECIPIENT_BLT);
+ CMD_STALL(buffer, SYNC_RECIPIENT_FE, SYNC_RECIPIENT_BLT);
+ CMD_LOAD_STATE(buffer, VIVS_BLT_ENABLE, 0x0);
+ }
CMD_LOAD_STATE(buffer, VIVS_GL_FLUSH_CACHE, flush);
- if (gpu->exec_state == ETNA_PIPE_3D)
- CMD_LOAD_STATE(buffer, VIVS_TS_FLUSH_CACHE,
- VIVS_TS_FLUSH_CACHE_FLUSH);
+ if (gpu->exec_state == ETNA_PIPE_3D) {
+ if (has_blt) {
+ CMD_LOAD_STATE(buffer, VIVS_BLT_ENABLE, 0x1);
+ CMD_LOAD_STATE(buffer, VIVS_BLT_SET_COMMAND, 0x1);
+ CMD_LOAD_STATE(buffer, VIVS_BLT_ENABLE, 0x0);
+ } else {
+ CMD_LOAD_STATE(buffer, VIVS_TS_FLUSH_CACHE,
+ VIVS_TS_FLUSH_CACHE_FLUSH);
+ }
+ }
CMD_SEM(buffer, SYNC_RECIPIENT_FE, SYNC_RECIPIENT_PE);
CMD_STALL(buffer, SYNC_RECIPIENT_FE, SYNC_RECIPIENT_PE);
+ if (has_blt) {
+ CMD_LOAD_STATE(buffer, VIVS_BLT_ENABLE, 0x1);
+ CMD_SEM(buffer, SYNC_RECIPIENT_FE, SYNC_RECIPIENT_BLT);
+ CMD_STALL(buffer, SYNC_RECIPIENT_FE, SYNC_RECIPIENT_BLT);
+ CMD_LOAD_STATE(buffer, VIVS_BLT_ENABLE, 0x0);
+ }
CMD_END(buffer);

etnaviv_buffer_replace_wait(buffer, waitlink_offset,
@@ -323,6 +348,8 @@ void etnaviv_buffer_queue(struct etnaviv
bool switch_mmu_context = gpu->mmu_context != mmu_context;
unsigned int new_flush_seq = READ_ONCE(gpu->mmu_context->flush_seq);
bool need_flush = switch_mmu_context || gpu->flush_seq != new_flush_seq;
+ bool has_blt = !!(gpu->identity.minor_features5 &
+ chipMinorFeatures5_BLT_ENGINE);

lockdep_assert_held(&gpu->lock);

@@ -433,6 +460,15 @@ void etnaviv_buffer_queue(struct etnaviv
* 2 semaphore stall + 1 event + 1 wait + 1 link.
*/
return_dwords = 7;
+
+ /*
+ * When the BLT engine is present we need 6 more dwords in the return
+ * target: 3 enable/flush/disable + 4 enable/semaphore stall/disable,
+ * but we don't need the normal TS flush state.
+ */
+ if (has_blt)
+ return_dwords += 6;
+
return_target = etnaviv_buffer_reserve(gpu, buffer, return_dwords);
CMD_LINK(cmdbuf, return_dwords, return_target);

@@ -447,11 +483,25 @@ void etnaviv_buffer_queue(struct etnaviv
CMD_LOAD_STATE(buffer, VIVS_GL_FLUSH_CACHE,
VIVS_GL_FLUSH_CACHE_DEPTH |
VIVS_GL_FLUSH_CACHE_COLOR);
- CMD_LOAD_STATE(buffer, VIVS_TS_FLUSH_CACHE,
- VIVS_TS_FLUSH_CACHE_FLUSH);
+ if (has_blt) {
+ CMD_LOAD_STATE(buffer, VIVS_BLT_ENABLE, 0x1);
+ CMD_LOAD_STATE(buffer, VIVS_BLT_SET_COMMAND, 0x1);
+ CMD_LOAD_STATE(buffer, VIVS_BLT_ENABLE, 0x0);
+ } else {
+ CMD_LOAD_STATE(buffer, VIVS_TS_FLUSH_CACHE,
+ VIVS_TS_FLUSH_CACHE_FLUSH);
+ }
}
CMD_SEM(buffer, SYNC_RECIPIENT_FE, SYNC_RECIPIENT_PE);
CMD_STALL(buffer, SYNC_RECIPIENT_FE, SYNC_RECIPIENT_PE);
+
+ if (has_blt) {
+ CMD_LOAD_STATE(buffer, VIVS_BLT_ENABLE, 0x1);
+ CMD_SEM(buffer, SYNC_RECIPIENT_FE, SYNC_RECIPIENT_BLT);
+ CMD_STALL(buffer, SYNC_RECIPIENT_FE, SYNC_RECIPIENT_BLT);
+ CMD_LOAD_STATE(buffer, VIVS_BLT_ENABLE, 0x0);
+ }
+
CMD_LOAD_STATE(buffer, VIVS_GL_EVENT, VIVS_GL_EVENT_EVENT_ID(event) |
VIVS_GL_EVENT_FROM_PE);
CMD_WAIT(buffer);
--- a/drivers/gpu/drm/etnaviv/state_blt.xml.h
+++ b/drivers/gpu/drm/etnaviv/state_blt.xml.h
@@ -46,6 +46,8 @@ DEALINGS IN THE SOFTWARE.

/* This is a cut-down version of the state_blt.xml.h file */

+#define VIVS_BLT_SET_COMMAND 0x000140ac
+
#define VIVS_BLT_ENABLE 0x000140b8
#define VIVS_BLT_ENABLE_ENABLE 0x00000001