[PATCH AUTOSEL 6.7 74/88] drm/amd/display: Fix minor issues in BW Allocation Phase2

Sasha Levin
2024-01-22T15:01:29Z

From: Meenakshikumar Somasundaram <meenakshikumar.somasundaram@amd.com>

[ Upstream commit aa5dc05340eb97486a631ce6bccb8d020bf6b56b ]

[Why]
Fix minor issues in BW Allocation Phase2.

[How]
- In set_usb4_req_bw_req(), link->dpia_bw_alloc_config.response_ready
flag should be reset before writing DPCD REQUEST_BW.
- Fix the granularity for value of 2 in get_bw_granularity().
- Removed bandwidth allocation support display fw boot option as
the fw would read feature enable status from bios.
- Clean up DPIA_EST_BW_CHANGED and DPIA_BW_REQ_SUCCESS cases in
dpia_handle_bw_alloc_response().
- Removed allocate_usb4_bw and deallocate_usb4_bw.
- Optimized loop in get_lowest_dpia_index().
- Updated link_dp_dpia_allocate_usb4_bandwidth_for_stream() and
set_usb4_req_bw_req() to always issue request bw.

Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Reviewed-by: PeiChen Huang <peichen.huang@amd.com>
Acked-by: Rodrigo Siqueira <rodrigo.siqueira@amd.com>
Signed-off-by: Meenakshikumar Somasundaram <meenakshikumar.somasundaram@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
.../dc/link/protocols/link_dp_dpia_bw.c | 221 ++++++++----------
.../dc/link/protocols/link_dp_dpia_bw.h | 4 +-
2 files changed, 101 insertions(+), 124 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_dpia_bw.c b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_dpia_bw.c
index 7581023daa47..d6e1f969bfd5 100644
--- a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_dpia_bw.c
+++ b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_dpia_bw.c
@@ -50,6 +50,7 @@ static bool get_bw_alloc_proceed_flag(struct dc_link *tmp)
&& tmp->hpd_status
&& tmp->dpia_bw_alloc_config.bw_alloc_enabled);
}
+
static void reset_bw_alloc_struct(struct dc_link *link)
{
link->dpia_bw_alloc_config.bw_alloc_enabled = false;
@@ -59,6 +60,11 @@ static void reset_bw_alloc_struct(struct dc_link *link)
link->dpia_bw_alloc_config.bw_granularity = 0;
link->dpia_bw_alloc_config.response_ready = false;
}
+
+#define BW_GRANULARITY_0 4 // 0.25 Gbps
+#define BW_GRANULARITY_1 2 // 0.5 Gbps
+#define BW_GRANULARITY_2 1 // 1 Gbps
+
static uint8_t get_bw_granularity(struct dc_link *link)
{
uint8_t bw_granularity = 0;
@@ -71,16 +77,20 @@ static uint8_t get_bw_granularity(struct dc_link *link)

switch (bw_granularity & 0x3) {
case 0:
- bw_granularity = 4;
+ bw_granularity = BW_GRANULARITY_0;
break;
case 1:
+ bw_granularity = BW_GRANULARITY_1;
+ break;
+ case 2:
default:
- bw_granularity = 2;
+ bw_granularity = BW_GRANULARITY_2;
break;
}

return bw_granularity;
}
+
static int get_estimated_bw(struct dc_link *link)
{
uint8_t bw_estimated_bw = 0;
@@ -93,31 +103,7 @@ static int get_estimated_bw(struct dc_link *link)

return bw_estimated_bw * (Kbps_TO_Gbps / link->dpia_bw_alloc_config.bw_granularity);
}
-static bool allocate_usb4_bw(int *stream_allocated_bw, int bw_needed, struct dc_link *link)
-{
- if (bw_needed > 0)
- *stream_allocated_bw += bw_needed;
-
- return true;
-}
-static bool deallocate_usb4_bw(int *stream_allocated_bw, int bw_to_dealloc, struct dc_link *link)
-{
- bool ret = false;
-
- if (*stream_allocated_bw > 0) {
- *stream_allocated_bw -= bw_to_dealloc;
- ret = true;
- } else {
- //Do nothing for now
- ret = true;
- }

- // Unplug so reset values
- if (!link->hpd_status)
- reset_bw_alloc_struct(link);
-
- return ret;
-}
/*
* Read all New BW alloc configuration ex: estimated_bw, allocated_bw,
* granuality, Driver_ID, CM_Group, & populate the BW allocation structs
@@ -128,7 +114,12 @@ static void init_usb4_bw_struct(struct dc_link *link)
// Init the known values
link->dpia_bw_alloc_config.bw_granularity = get_bw_granularity(link);
link->dpia_bw_alloc_config.estimated_bw = get_estimated_bw(link);
+
+ DC_LOG_DEBUG("%s: bw_granularity(%d), estimated_bw(%d)\n",
+ __func__, link->dpia_bw_alloc_config.bw_granularity,
+ link->dpia_bw_alloc_config.estimated_bw);
}
+
static uint8_t get_lowest_dpia_index(struct dc_link *link)
{
const struct dc *dc_struct = link->dc;
@@ -141,12 +132,15 @@ static uint8_t get_lowest_dpia_index(struct dc_link *link)
dc_struct->links[i]->ep_type != DISPLAY_ENDPOINT_USB4_DPIA)
continue;

- if (idx > dc_struct->links[i]->link_index)
+ if (idx > dc_struct->links[i]->link_index) {
idx = dc_struct->links[i]->link_index;
+ break;
+ }
}

return idx;
}
+
/*
* Get the Max Available BW or Max Estimated BW for each Host Router
*
@@ -186,6 +180,7 @@ static int get_host_router_total_bw(struct dc_link *link, uint8_t type)

return total_bw;
}
+
/*
* Cleanup function for when the dpia is unplugged to reset struct
* and perform any required clean up
@@ -194,42 +189,50 @@ static int get_host_router_total_bw(struct dc_link *link, uint8_t type)
*
* return: none
*/
-static bool dpia_bw_alloc_unplug(struct dc_link *link)
+static void dpia_bw_alloc_unplug(struct dc_link *link)
{
- if (!link)
- return true;
-
- return deallocate_usb4_bw(&link->dpia_bw_alloc_config.sink_allocated_bw,
- link->dpia_bw_alloc_config.sink_allocated_bw, link);
+ if (link) {
+ DC_LOG_DEBUG("%s: resetting bw alloc config for link(%d)\n",
+ __func__, link->link_index);
+ link->dpia_bw_alloc_config.sink_allocated_bw = 0;
+ reset_bw_alloc_struct(link);
+ }
}
+
static void set_usb4_req_bw_req(struct dc_link *link, int req_bw)
{
uint8_t requested_bw;
uint32_t temp;

- // 1. Add check for this corner case #1
- if (req_bw > link->dpia_bw_alloc_config.estimated_bw)
+ /* Error check whether request bw greater than allocated */
+ if (req_bw > link->dpia_bw_alloc_config.estimated_bw) {
+ DC_LOG_ERROR("%s: Request bw greater than estimated bw for link(%d)\n",
+ __func__, link->link_index);
req_bw = link->dpia_bw_alloc_config.estimated_bw;
+ }

temp = req_bw * link->dpia_bw_alloc_config.bw_granularity;
requested_bw = temp / Kbps_TO_Gbps;

- // Always make sure to add more to account for floating points
+ /* Always make sure to add more to account for floating points */
if (temp % Kbps_TO_Gbps)
++requested_bw;

- // 2. Add check for this corner case #2
+ /* Error check whether requested and allocated are equal */
req_bw = requested_bw * (Kbps_TO_Gbps / link->dpia_bw_alloc_config.bw_granularity);
- if (req_bw == link->dpia_bw_alloc_config.sink_allocated_bw)
- return;
+ if (req_bw == link->dpia_bw_alloc_config.sink_allocated_bw) {
+ DC_LOG_ERROR("%s: Request bw equals to allocated bw for link(%d)\n",
+ __func__, link->link_index);
+ }

- if (core_link_write_dpcd(
+ link->dpia_bw_alloc_config.response_ready = false; // Reset flag
+ core_link_write_dpcd(
link,
REQUESTED_BW,
&requested_bw,
- sizeof(uint8_t)) == DC_OK)
- link->dpia_bw_alloc_config.response_ready = false; // Reset flag
+ sizeof(uint8_t));
}
+
/*
* Return the response_ready flag from dc_link struct
*
@@ -241,6 +244,7 @@ static bool get_cm_response_ready_flag(struct dc_link *link)
{
return link->dpia_bw_alloc_config.response_ready;
}
+
// ------------------------------------------------------------------
// PUBLIC FUNCTIONS
// ------------------------------------------------------------------
@@ -277,27 +281,27 @@ bool link_dp_dpia_set_dptx_usb4_bw_alloc_support(struct dc_link *link)
DPTX_BW_ALLOCATION_MODE_CONTROL,
&response,
sizeof(uint8_t)) != DC_OK) {
- DC_LOG_DEBUG("%s: **** FAILURE Enabling DPtx BW Allocation Mode Support ***\n",
- __func__);
+ DC_LOG_DEBUG("%s: FAILURE Enabling DPtx BW Allocation Mode Support for link(%d)\n",
+ __func__, link->link_index);
} else {
// SUCCESS Enabled DPtx BW Allocation Mode Support
- link->dpia_bw_alloc_config.bw_alloc_enabled = true;
- DC_LOG_DEBUG("%s: **** SUCCESS Enabling DPtx BW Allocation Mode Support ***\n",
- __func__);
+ DC_LOG_DEBUG("%s: SUCCESS Enabling DPtx BW Allocation Mode Support for link(%d)\n",
+ __func__, link->link_index);

ret = true;
init_usb4_bw_struct(link);
+ link->dpia_bw_alloc_config.bw_alloc_enabled = true;
}
}

out:
return ret;
}
+
void dpia_handle_bw_alloc_response(struct dc_link *link, uint8_t bw, uint8_t result)
{
int bw_needed = 0;
int estimated = 0;
- int host_router_total_estimated_bw = 0;

if (!get_bw_alloc_proceed_flag((link)))
return;
@@ -306,14 +310,22 @@ void dpia_handle_bw_alloc_response(struct dc_link *link, uint8_t bw, uint8_t res

case DPIA_BW_REQ_FAILED:

- DC_LOG_DEBUG("%s: *** *** BW REQ FAILURE for DP-TX Request *** ***\n", __func__);
+ /*
+ * Ideally, we shouldn't run into this case as we always validate available
+ * bandwidth and request within that limit
+ */
+ estimated = bw * (Kbps_TO_Gbps / link->dpia_bw_alloc_config.bw_granularity);

- // Update the new Estimated BW value updated by CM
- link->dpia_bw_alloc_config.estimated_bw =
- bw * (Kbps_TO_Gbps / link->dpia_bw_alloc_config.bw_granularity);
+ DC_LOG_ERROR("%s: BW REQ FAILURE for DP-TX Request for link(%d)\n",
+ __func__, link->link_index);
+ DC_LOG_ERROR("%s: current estimated_bw(%d), new estimated_bw(%d)\n",
+ __func__, link->dpia_bw_alloc_config.estimated_bw, estimated);

+ /* Update the new Estimated BW value updated by CM */
+ link->dpia_bw_alloc_config.estimated_bw = estimated;
+
+ /* Allocate the previously requested bandwidth */
set_usb4_req_bw_req(link, link->dpia_bw_alloc_config.estimated_bw);
- link->dpia_bw_alloc_config.response_ready = false;

/*
* If FAIL then it is either:
@@ -326,68 +338,34 @@ void dpia_handle_bw_alloc_response(struct dc_link *link, uint8_t bw, uint8_t res

case DPIA_BW_REQ_SUCCESS:

- DC_LOG_DEBUG("%s: *** BW REQ SUCCESS for DP-TX Request ***\n", __func__);
-
- // 1. SUCCESS 1st time before any Pruning is done
- // 2. SUCCESS after prev. FAIL before any Pruning is done
- // 3. SUCCESS after Pruning is done but before enabling link
-
bw_needed = bw * (Kbps_TO_Gbps / link->dpia_bw_alloc_config.bw_granularity);

- // 1.
- if (!link->dpia_bw_alloc_config.sink_allocated_bw) {
-
- allocate_usb4_bw(&link->dpia_bw_alloc_config.sink_allocated_bw, bw_needed, link);
- link->dpia_bw_alloc_config.sink_verified_bw =
- link->dpia_bw_alloc_config.sink_allocated_bw;
+ DC_LOG_DEBUG("%s: BW REQ SUCCESS for DP-TX Request for link(%d)\n",
+ __func__, link->link_index);
+ DC_LOG_DEBUG("%s: current allocated_bw(%d), new allocated_bw(%d)\n",
+ __func__, link->dpia_bw_alloc_config.sink_allocated_bw, bw_needed);

- // SUCCESS from first attempt
- if (link->dpia_bw_alloc_config.sink_allocated_bw >
- link->dpia_bw_alloc_config.sink_max_bw)
- link->dpia_bw_alloc_config.sink_verified_bw =
- link->dpia_bw_alloc_config.sink_max_bw;
- }
- // 3.
- else if (link->dpia_bw_alloc_config.sink_allocated_bw) {
-
- // Find out how much do we need to de-alloc
- if (link->dpia_bw_alloc_config.sink_allocated_bw > bw_needed)
- deallocate_usb4_bw(&link->dpia_bw_alloc_config.sink_allocated_bw,
- link->dpia_bw_alloc_config.sink_allocated_bw - bw_needed, link);
- else
- allocate_usb4_bw(&link->dpia_bw_alloc_config.sink_allocated_bw,
- bw_needed - link->dpia_bw_alloc_config.sink_allocated_bw, link);
- }
-
- // 4. If this is the 2nd sink then any unused bw will be reallocated to master DPIA
- // => check if estimated_bw changed
+ link->dpia_bw_alloc_config.sink_allocated_bw = bw_needed;

link->dpia_bw_alloc_config.response_ready = true;
break;

case DPIA_EST_BW_CHANGED:

- DC_LOG_DEBUG("%s: *** ESTIMATED BW CHANGED for DP-TX Request ***\n", __func__);
-
estimated = bw * (Kbps_TO_Gbps / link->dpia_bw_alloc_config.bw_granularity);
- host_router_total_estimated_bw = get_host_router_total_bw(link, HOST_ROUTER_BW_ESTIMATED);

- // 1. If due to unplug of other sink
- if (estimated == host_router_total_estimated_bw) {
- // First update the estimated & max_bw fields
- if (link->dpia_bw_alloc_config.estimated_bw < estimated)
- link->dpia_bw_alloc_config.estimated_bw = estimated;
- }
- // 2. If due to realloc bw btw 2 dpia due to plug OR realloc unused Bw
- else {
- // We lost estimated bw usually due to plug event of other dpia
- link->dpia_bw_alloc_config.estimated_bw = estimated;
- }
+ DC_LOG_DEBUG("%s: ESTIMATED BW CHANGED for link(%d)\n",
+ __func__, link->link_index);
+ DC_LOG_DEBUG("%s: current estimated_bw(%d), new estimated_bw(%d)\n",
+ __func__, link->dpia_bw_alloc_config.estimated_bw, estimated);
+
+ link->dpia_bw_alloc_config.estimated_bw = estimated;
break;

case DPIA_BW_ALLOC_CAPS_CHANGED:

- DC_LOG_DEBUG("%s: *** BW ALLOC CAPABILITY CHANGED for DP-TX Request ***\n", __func__);
+ DC_LOG_ERROR("%s: BW ALLOC CAPABILITY CHANGED to Disabled for link(%d)\n",
+ __func__, link->link_index);
link->dpia_bw_alloc_config.bw_alloc_enabled = false;
break;
}
@@ -409,11 +387,11 @@ int dpia_handle_usb4_bandwidth_allocation_for_link(struct dc_link *link, int pea
set_usb4_req_bw_req(link, link->dpia_bw_alloc_config.sink_max_bw);

do {
- if (!(timeout > 0))
+ if (timeout > 0)
timeout--;
else
break;
- fsleep(10 * 1000);
+ msleep(10);
} while (!get_cm_response_ready_flag(link));

if (!timeout)
@@ -428,37 +406,36 @@ int dpia_handle_usb4_bandwidth_allocation_for_link(struct dc_link *link, int pea
out:
return ret;
}
-int link_dp_dpia_allocate_usb4_bandwidth_for_stream(struct dc_link *link, int req_bw)
+
+bool link_dp_dpia_allocate_usb4_bandwidth_for_stream(struct dc_link *link, int req_bw)
{
- int ret = 0;
+ bool ret = false;
uint8_t timeout = 10;

+ DC_LOG_DEBUG("%s: ENTER: link(%d), hpd_status(%d), current allocated_bw(%d), req_bw(%d)\n",
+ __func__, link->link_index, link->hpd_status,
+ link->dpia_bw_alloc_config.sink_allocated_bw, req_bw);
+
if (!get_bw_alloc_proceed_flag(link))
goto out;

- /*
- * Sometimes stream uses same timing parameters as the already
- * allocated max sink bw so no need to re-alloc
- */
- if (req_bw != link->dpia_bw_alloc_config.sink_allocated_bw) {
- set_usb4_req_bw_req(link, req_bw);
- do {
- if (!(timeout > 0))
- timeout--;
- else
- break;
- udelay(10 * 1000);
- } while (!get_cm_response_ready_flag(link));
+ set_usb4_req_bw_req(link, req_bw);
+ do {
+ if (timeout > 0)
+ timeout--;
+ else
+ break;
+ msleep(10);
+ } while (!get_cm_response_ready_flag(link));

- if (!timeout)
- ret = 0;// ERROR TIMEOUT waiting for response for allocating bw
- else if (link->dpia_bw_alloc_config.sink_allocated_bw > 0)
- ret = get_host_router_total_bw(link, HOST_ROUTER_BW_ALLOCATED);
- }
+ if (timeout)
+ ret = true;

out:
+ DC_LOG_DEBUG("%s: EXIT: timeout(%d), ret(%d)\n", __func__, timeout, ret);
return ret;
}
+
bool dpia_validate_usb4_bw(struct dc_link **link, int *bw_needed_per_dpia, const unsigned int num_dpias)
{
bool ret = true;
diff --git a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_dpia_bw.h b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_dpia_bw.h
index 7292690383ae..981bc4eb6120 100644
--- a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_dpia_bw.h
+++ b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_dpia_bw.h
@@ -59,9 +59,9 @@ bool link_dp_dpia_set_dptx_usb4_bw_alloc_support(struct dc_link *link);
* @link: pointer to the dc_link struct instance
* @req_bw: Bw requested by the stream
*
- * return: allocated bw else return 0
+ * return: true if allocated successfully
*/
-int link_dp_dpia_allocate_usb4_bandwidth_for_stream(struct dc_link *link, int req_bw);
+bool link_dp_dpia_allocate_usb4_bandwidth_for_stream(struct dc_link *link, int req_bw);

/*
* Handle the USB4 BW Allocation related functionality here:
--
2.43.0