drm/msm/a6xx: Avoid freeing gmu resources multiple times

The driver checks for gmu->mmio as a sign that the device has been
initialized, however there are failures in probe below the mmio init.
If one of those is hit, mmio will be non-null but freed.

In that case, a6xx_gmu_probe will return an error to a6xx_gpu_init which
will in turn call a6xx_gmu_remove which checks gmu->mmio and tries to free
resources for a second time. This causes a great boom.

Fix this by adding an initialized member to gmu which is set on
successful probe and cleared on removal.

Changes in v2:
- None

Cc: Jordan Crouse <[e-mail]>
Reviewed-by: Jordan Crouse <[e-mail]>
Signed-off-by: Sean Paul <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/msm/adreno/a6xx_gmu.c

···
 	u32 val;
 
 	/* This can be called from gpu state code so make sure GMU is valid */
-	if (IS_ERR_OR_NULL(gmu->mmio))
+	if (!gmu->initialized)
 		return false;
 
 	val = gmu_read(gmu, REG_A6XX_GMU_SPTPRAC_PWR_CLK_STATUS);
···
 	u32 val;
 
 	/* This can be called from gpu state code so make sure GMU is valid */
-	if (IS_ERR_OR_NULL(gmu->mmio))
+	if (!gmu->initialized)
 		return false;
 
 	val = gmu_read(gmu, REG_A6XX_GMU_SPTPRAC_PWR_CLK_STATUS);
···
 	struct a6xx_gmu *gmu = &a6xx_gpu->gmu;
 	int status, ret;
 
-	if (WARN(!gmu->mmio, "The GMU is not set up yet\n"))
+	if (WARN(!gmu->initialized, "The GMU is not set up yet\n"))
 		return 0;
 
 	gmu->hung = false;
···
 {
 	u32 reg;
 
-	if (!gmu->mmio)
+	if (!gmu->initialized)
 		return true;
 
 	reg = gmu_read(gmu, REG_A6XX_GPU_GMU_AO_GPU_CX_BUSY_STATUS);
···
 {
 	struct a6xx_gmu *gmu = &a6xx_gpu->gmu;
 
-	if (IS_ERR_OR_NULL(gmu->mmio))
+	if (!gmu->initialized)
 		return;
 
 	a6xx_gmu_stop(a6xx_gpu);
···
 	iommu_detach_device(gmu->domain, gmu->dev);
 
 	iommu_domain_free(gmu->domain);
+
+	gmu->initialized = false;
 }
 
 int a6xx_gmu_probe(struct a6xx_gpu *a6xx_gpu, struct device_node *node)
···
 
 	/* Set up the HFI queues */
 	a6xx_hfi_init(gmu);
+
+	gmu->initialized = true;
 
 	return 0;
 err:

drivers/gpu/drm/msm/adreno/a6xx_gmu.h

···
 
 	struct a6xx_hfi_queue queues[2];
 
+	bool initialized;
 	bool hung;
 };