Am 27.03.25 um 14:52 schrieb Maíra Canal:
Hi Stefan,
On 27/03/25 07:57, Stefan Wahren wrote:
Hi Maíra,
Am 18.03.25 um 02:01 schrieb Maíra Canal:
In addition to the standard reset controller, V3D 7.x requires
configuring
the V3D_SMS registers for proper power on/off and reset. Add the new
registers to `v3d_regs.h` and ensure they are properly configured
during
device probing, removal, and reset.
This change fixes GPU reset issues on the Raspberry Pi 5 (BCM2712).
Without exposing these registers, a GPU reset causes the GPU to hang,
stopping any further job execution and freezing the desktop GUI. The
same
issue occurs when unloading and loading the v3d driver.
Link: https://github.com/raspberrypi/linux/issues/6660
Reviewed-by: Iago Toral Quiroga <ito...@igalia.com>
Signed-off-by: Maíra Canal <mca...@igalia.com>
---
drivers/gpu/drm/v3d/v3d_drv.c | 40
++++++++++++++++++++++++++++++++ ++++++++
drivers/gpu/drm/v3d/v3d_drv.h | 11 +++++++++++
drivers/gpu/drm/v3d/v3d_gem.c | 17 +++++++++++++++++
drivers/gpu/drm/v3d/v3d_regs.h | 26 ++++++++++++++++++++++++++
4 files changed, 94 insertions(+)
diff --git a/drivers/gpu/drm/v3d/v3d_drv.c b/drivers/gpu/drm/v3d/
v3d_drv.c
index
c63f0ed1bd8a3d5511085e76ed2fbd6ee7df6f80..122848cdccc4a02039d9ea2e77aa2f377886b5d6
100644
--- a/drivers/gpu/drm/v3d/v3d_drv.c
+++ b/drivers/gpu/drm/v3d/v3d_drv.c
@@ -263,6 +263,36 @@ static const struct of_device_id v3d_of_match[]
= {
};
MODULE_DEVICE_TABLE(of, v3d_of_match);
+static void
+v3d_idle_sms(struct v3d_dev *v3d)
+{
+ if (v3d->ver < V3D_GEN_71)
+ return;
+
+ V3D_SMS_WRITE(V3D_SMS_TEE_CS, V3D_SMS_CLEAR_POWER_OFF);
+
+ if (wait_for((V3D_GET_FIELD(V3D_SMS_READ(V3D_SMS_TEE_CS),
+ V3D_SMS_STATE) == V3D_SMS_IDLE), 100)) {
+ DRM_ERROR("Failed to power up SMS\n");
+ }
+
+ v3d_reset_sms(v3d);
+}
+
+static void
+v3d_power_off_sms(struct v3d_dev *v3d)
+{
+ if (v3d->ver < V3D_GEN_71)
+ return;
+
+ V3D_SMS_WRITE(V3D_SMS_TEE_CS, V3D_SMS_POWER_OFF);
+
+ if (wait_for((V3D_GET_FIELD(V3D_SMS_READ(V3D_SMS_TEE_CS),
+ V3D_SMS_STATE) == V3D_SMS_POWER_OFF_STATE),
100)) {
+ DRM_ERROR("Failed to power off SMS\n");
+ }
+}
+
static int
map_regs(struct v3d_dev *v3d, void __iomem **regs, const char *name)
{
@@ -300,6 +330,12 @@ static int v3d_platform_drm_probe(struct
platform_device *pdev)
if (ret)
return ret;
+ if (v3d->ver >= V3D_GEN_71) {
+ ret = map_regs(v3d, &v3d->sms_regs, "sms");
+ if (ret)
+ return ret;
Is it correct, that BCM2712 now requires the SMS register and otherwise
the driver doesn't probe?
Hum, yeah, it is correct, but I can send a patch to ensure backwards
compatibility. But keep in mind that you won't be able to reset the GPU
or unload/load (power on/off).
Just a note for the future: the devicetree is considered as an ABI [1],
so new kernels should still work with old DTB (no regression). For
Raspberry Pi OS, the kernel and DTB are always updated, but this doesn't
apply for Linux Mainline. AFAIK V3D doesn't work with Linux Mainline on
Raspberry Pi 5 yet, so this is just a theoretical problem.
Yeah, I had that in mind, but due to the reason pointed in the end of
your comment, it was okay to do so and ensure that reset and power on/
off will work when RPi 5 reach upstream support.
Fine :-)
But, I'm open to send a patch removing the requirement.
I think, this is not necessary. There is no need to introduce such
"complexity".
Best Regards,
- Maíra
Best regards
[1] - https://docs.kernel.org/devicetree/bindings/ABI.html
