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drm/amd/display: Poll for GPUVM context ready (v2)

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[Why]
Hardware docs state that we must wait until the GPUVM context is ready
after programming it.

[How]
Poll until the valid bit of PAGE_TABLE_BASE_ADDR_LO32 is set to 1 after
programming it.

v2: fix include for udelay (Alex)

Signed-off-by: Julian Parkin <julian.parkin@amd.com>
Reviewed-by: Charlene Liu <Charlene.Liu@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This commit is contained in:
Julian Parkin 2019-06-13 12:49:37 -04:00 committed by Alex Deucher
parent dd5d9348da
commit ca6f188cdf
1 changed files with 37 additions and 0 deletions
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37
drivers/gpu/drm/amd/display/dc/dcn20/dcn20_vmid.c
View File

@ -23,6 +23,8 @@
*
*/
#include <linux/delay.h>
#include "dcn20_vmid.h"
#include "reg_helper.h"
@ -36,6 +38,38 @@
#define FN(reg_name, field_name) \
vmid->shifts->field_name, vmid->masks->field_name
static void dcn20_wait_for_vmid_ready(struct dcn20_vmid *vmid)
{
/* According the hardware spec, we need to poll for the lowest
* bit of PAGE_TABLE_BASE_ADDR_LO32 = 1 any time a GPUVM
* context is updated. We can't use REG_WAIT here since we
* don't have a seperate field to wait on.
*
* TODO: Confirm timeout / poll interval with hardware team
*/
int max_times = 10000;
int delay_us = 5;
int i;
for (i = 0; i < max_times; ++i) {
uint32_t entry_lo32;
REG_GET(PAGE_TABLE_BASE_ADDR_LO32,
VM_CONTEXT0_PAGE_DIRECTORY_ENTRY_LO32,
&entry_lo32);
if (entry_lo32 & 0x1)
return;
udelay(delay_us);
}
/* VM setup timed out */
DC_LOG_WARNING("Timeout while waiting for GPUVM context update\n");
ASSERT(0);
}
void dcn20_vmid_setup(struct dcn20_vmid *vmid, const struct dcn_vmid_page_table_config *config)
{
REG_SET(PAGE_TABLE_START_ADDR_HI32, 0,
@ -54,6 +88,9 @@ void dcn20_vmid_setup(struct dcn20_vmid *vmid, const struct dcn_vmid_page_table_
REG_SET(PAGE_TABLE_BASE_ADDR_HI32, 0,
VM_CONTEXT0_PAGE_DIRECTORY_ENTRY_HI32, (config->page_table_base_addr >> 32) & 0xFFFFFFFF);
/* Note: per hardware spec PAGE_TABLE_BASE_ADDR_LO32 must be programmed last in sequence */
REG_SET(PAGE_TABLE_BASE_ADDR_LO32, 0,
VM_CONTEXT0_PAGE_DIRECTORY_ENTRY_LO32, config->page_table_base_addr & 0xFFFFFFFF);
dcn20_wait_for_vmid_ready(vmid);
}