This is a note to let you know that I've just added the patch titled
drm/panfrost: Really power off GPU cores in panfrost_gpu_power_off()
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-panfrost-really-power-off-gpu-cores-in-panfrost_.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit c6fba450f4dec69820157802fde0a2e7e9d54f88
Author: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>
Date: Thu Nov 2 15:15:07 2023 +0100
drm/panfrost: Really power off GPU cores in panfrost_gpu_power_off()
[ Upstream commit 22aa1a209018dc2eca78745f7666db63637cd5dc ]
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: f3ba91228e8e ("drm/panfrost: Add initial panfrost driver")
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>
Reviewed-by: Steven Price <steven.price@xxxxxxx>
Signed-off-by: Steven Price <steven.price@xxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20231102141507.73481-1-angelogioacchino.delregno@xxxxxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/gpu/drm/panfrost/panfrost_gpu.c b/drivers/gpu/drm/panfrost/panfrost_gpu.c
index d28b99732dde..e20619169fe1 100644
--- a/drivers/gpu/drm/panfrost/panfrost_gpu.c
+++ b/drivers/gpu/drm/panfrost/panfrost_gpu.c
@@ -321,28 +321,38 @@ static void panfrost_gpu_init_features(struct panfrost_device *pfdev)
pfdev->features.shader_present, pfdev->features.l2_present);
}
+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),
@@ -367,9 +377,27 @@ 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)
