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drm/panfrost: Really power off GPU cores in panfrost_gpu_power_off()

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The layout of the registers {TILER,SHADER,L2}_PWROFF_LO, used to request
powering off cores, is the same as the {TILER,SHADER,L2}_PWRON_LO ones:
this means that in order to request poweroff of cores, we are supposed
to write a bitmask of cores that should be powered off!
This means that the panfrost_gpu_power_off() function has always been
doing nothing.

Fix powering off the GPU by writing a bitmask of the cores to poweroff
to the relevant PWROFF_LO registers and then check that the transition
(from ON to OFF) has finished by polling the relevant PWRTRANS_LO
registers.

While at it, in order to avoid code duplication, move the core mask
logic from panfrost_gpu_power_on() to a new panfrost_get_core_mask()
function, used in both poweron and poweroff.

Fixes: f3ba91228e ("drm/panfrost: Add initial panfrost driver")
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Signed-off-by: Steven Price <steven.price@arm.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231102141507.73481-1-angelogioacchino.delregno@collabora.com
This commit is contained in:
AngeloGioacchino Del Regno 2023-11-02 15:15:07 +01:00 committed by Steven Price
parent a78422e9df
commit 22aa1a2090
1 changed files with 46 additions and 18 deletions
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64
drivers/gpu/drm/panfrost/panfrost_gpu.c
View file

@ -362,28 +362,38 @@ unsigned long long panfrost_cycle_counter_read(struct panfrost_device *pfdev)
return ((u64)hi << 32) | lo;
}
static u64 panfrost_get_core_mask(struct panfrost_device *pfdev)
{
u64 core_mask;
if (pfdev->features.l2_present == 1)
return U64_MAX;
/*
* Only support one core group now.
* ~(l2_present - 1) unsets all bits in l2_present except
* the bottom bit. (l2_present - 2) has all the bits in
* the first core group set. AND them together to generate
* a mask of cores in the first core group.
*/
core_mask = ~(pfdev->features.l2_present - 1) &
(pfdev->features.l2_present - 2);
dev_info_once(pfdev->dev, "using only 1st core group (%lu cores from %lu)\n",
hweight64(core_mask),
hweight64(pfdev->features.shader_present));
return core_mask;
}
void panfrost_gpu_power_on(struct panfrost_device *pfdev)
{
int ret;
u32 val;
u64 core_mask = U64_MAX;
u64 core_mask;
panfrost_gpu_init_quirks(pfdev);
core_mask = panfrost_get_core_mask(pfdev);
if (pfdev->features.l2_present != 1) {
/*
* Only support one core group now.
* ~(l2_present - 1) unsets all bits in l2_present except
* the bottom bit. (l2_present - 2) has all the bits in
* the first core group set. AND them together to generate
* a mask of cores in the first core group.
*/
core_mask = ~(pfdev->features.l2_present - 1) &
(pfdev->features.l2_present - 2);
dev_info_once(pfdev->dev, "using only 1st core group (%lu cores from %lu)\n",
hweight64(core_mask),
hweight64(pfdev->features.shader_present));
}
gpu_write(pfdev, L2_PWRON_LO, pfdev->features.l2_present & core_mask);
ret = readl_relaxed_poll_timeout(pfdev->iomem + L2_READY_LO,
val, val == (pfdev->features.l2_present & core_mask),
@ -408,9 +418,27 @@ void panfrost_gpu_power_on(struct panfrost_device *pfdev)
void panfrost_gpu_power_off(struct panfrost_device *pfdev)
{
gpu_write(pfdev, TILER_PWROFF_LO, 0);
gpu_write(pfdev, SHADER_PWROFF_LO, 0);
gpu_write(pfdev, L2_PWROFF_LO, 0);
u64 core_mask = panfrost_get_core_mask(pfdev);
int ret;
u32 val;
gpu_write(pfdev, SHADER_PWROFF_LO, pfdev->features.shader_present & core_mask);
ret = readl_relaxed_poll_timeout(pfdev->iomem + SHADER_PWRTRANS_LO,
val, !val, 1, 1000);
if (ret)
dev_err(pfdev->dev, "shader power transition timeout");
gpu_write(pfdev, TILER_PWROFF_LO, pfdev->features.tiler_present);
ret = readl_relaxed_poll_timeout(pfdev->iomem + TILER_PWRTRANS_LO,
val, !val, 1, 1000);
if (ret)
dev_err(pfdev->dev, "tiler power transition timeout");
gpu_write(pfdev, L2_PWROFF_LO, pfdev->features.l2_present & core_mask);
ret = readl_poll_timeout(pfdev->iomem + L2_PWRTRANS_LO,
val, !val, 0, 1000);
if (ret)
dev_err(pfdev->dev, "l2 power transition timeout");
}
int panfrost_gpu_init(struct panfrost_device *pfdev)