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drm/panthor: Explicitly set the coherency mode

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This commit fixes the potential misalignment between the value of device
tree property "dma-coherent" and default value of COHERENCY_ENABLE
register.
Panthor driver didn't explicitly program the COHERENCY_ENABLE register
with the desired coherency mode. The default value of COHERENCY_ENABLE
register is implementation defined, so it may not be always aligned with
the "dma-coherent" property value.
The commit also checks the COHERENCY_FEATURES register to confirm that
the coherency protocol is actually supported or not.

v2:
- Added R-b tags

Signed-off-by: Akash Goel <akash.goel@arm.com>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Liviu Dudau <liviu.dudau@arm.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Link: https://lore.kernel.org/r/20241030225407.4077513-3-akash.goel@arm.com
Signed-off-by: Liviu Dudau <liviu.dudau@arm.com>
This commit is contained in:
Akash Goel 2024-10-30 22:54:06 +00:00 • committed by Liviu Dudau
parent 06e931e0fc
commit dd7db8d911
2 changed files with 30 additions and 1 deletions
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22
drivers/gpu/drm/panthor/panthor_device.c
View file

@ -22,6 +22,24 @@
#include "panthor_regs.h"
#include "panthor_sched.h"
static int panthor_gpu_coherency_init(struct panthor_device *ptdev)
{
ptdev->coherent = device_get_dma_attr(ptdev->base.dev) == DEV_DMA_COHERENT;
if (!ptdev->coherent)
return 0;
/* Check if the ACE-Lite coherency protocol is actually supported by the GPU.
* ACE protocol has never been supported for command stream frontend GPUs.
*/
if ((gpu_read(ptdev, GPU_COHERENCY_FEATURES) &
GPU_COHERENCY_PROT_BIT(ACE_LITE)))
return 0;
drm_err(&ptdev->base, "Coherency not supported by the device");
return -ENOTSUPP;
}
static int panthor_clk_init(struct panthor_device *ptdev)
{
ptdev->clks.core = devm_clk_get(ptdev->base.dev, NULL);
@ -156,7 +174,9 @@ int panthor_device_init(struct panthor_device *ptdev)
struct page *p;
int ret;
ptdev->coherent = device_get_dma_attr(ptdev->base.dev) == DEV_DMA_COHERENT;
ret = panthor_gpu_coherency_init(ptdev);
if (ret)
return ret;
init_completion(&ptdev->unplug.done);
ret = drmm_mutex_init(&ptdev->base, &ptdev->unplug.lock);

9
drivers/gpu/drm/panthor/panthor_gpu.c
View file

@ -77,6 +77,12 @@ static const struct panthor_model gpu_models[] = {
GPU_IRQ_RESET_COMPLETED | \
GPU_IRQ_CLEAN_CACHES_COMPLETED)
static void panthor_gpu_coherency_set(struct panthor_device *ptdev)
{
gpu_write(ptdev, GPU_COHERENCY_PROTOCOL,
ptdev->coherent ? GPU_COHERENCY_PROT_BIT(ACE_LITE) : GPU_COHERENCY_NONE);
}
static void panthor_gpu_init_info(struct panthor_device *ptdev)
{
const struct panthor_model *model;
@ -365,6 +371,9 @@ int panthor_gpu_l2_power_on(struct panthor_device *ptdev)
hweight64(ptdev->gpu_info.shader_present));
}
/* Set the desired coherency mode before the power up of L2 */
panthor_gpu_coherency_set(ptdev);
return panthor_gpu_power_on(ptdev, L2, 1, 20000);
}