[Intel-gfx] [PATCH v2 5/6] drm/i915: Don't clobber the GTT when it's within stolen memory
Jani Nikula
jani.nikula at linux.intel.com
Mon Jun 30 12:25:29 CEST 2014
On Thu, 05 Jun 2014, ville.syrjala at linux.intel.com wrote:
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
>
> On most gen2-4 platforms the GTT can be (or maybe always is?)
> inside the stolen memory region. If that's the case, reduce the
> size of the stolen memory appropriately to make make sure we
> don't clobber the GTT.
>
> v2: Deal with gen4 36 bit physical address
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=80151
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> ---
> drivers/gpu/drm/i915/i915_gem_stolen.c | 44 ++++++++++++++++++++++++++++++++++
> drivers/gpu/drm/i915/i915_reg.h | 3 +++
> 2 files changed, 47 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/i915_gem_stolen.c b/drivers/gpu/drm/i915/i915_gem_stolen.c
> index 62ef55b..7465ab0 100644
> --- a/drivers/gpu/drm/i915/i915_gem_stolen.c
> +++ b/drivers/gpu/drm/i915/i915_gem_stolen.c
> @@ -74,6 +74,50 @@ static unsigned long i915_stolen_to_physical(struct drm_device *dev)
> if (base == 0)
> return 0;
>
> + /* make sure we don't clobber the GTT if it's within stolen memory */
> + if (INTEL_INFO(dev)->gen <= 4 && !IS_G33(dev) && !IS_G4X(dev)) {
> + struct {
> + u32 start, end;
> + } stolen[2] = {
> + { .start = base, .end = base + dev_priv->gtt.stolen_size, },
> + { .start = base, .end = base + dev_priv->gtt.stolen_size, },
> + };
> + u64 gtt_start, gtt_end;
> +
> + gtt_start = I915_READ(PGTBL_CTL);
> + if (IS_GEN4(dev))
> + gtt_start = (gtt_start & PGTBL_ADDRESS_LO_MASK) |
> + (gtt_start & PGTBL_ADDRESS_HI_MASK) << 28;
> + else
> + gtt_start &= PGTBL_ADDRESS_LO_MASK;
> + gtt_end = gtt_start + gtt_total_entries(dev_priv->gtt) * 4;
> +
> + if (gtt_start >= stolen[0].start && gtt_start < stolen[0].end)
> + stolen[0].end = gtt_start;
> + if (gtt_end > stolen[1].start && gtt_end <= stolen[1].end)
> + stolen[1].start = gtt_end;
> +
> + /* pick the larger of the two chunks */
> + if (stolen[0].end - stolen[0].start >
> + stolen[1].end - stolen[1].start) {
> + base = stolen[0].start;
> + dev_priv->gtt.stolen_size = stolen[0].end - stolen[0].start;
> + } else {
> + base = stolen[1].start;
> + dev_priv->gtt.stolen_size = stolen[1].end - stolen[1].start;
> + }
> +
> + if (stolen[0].start != stolen[1].start ||
> + stolen[0].end != stolen[1].end) {
> + DRM_DEBUG_KMS("GTT within stolen memory at 0x%llx-0x%llx\n",
> + (unsigned long long) gtt_start,
> + (unsigned long long) gtt_end - 1);
> + DRM_DEBUG_KMS("Stolen memory adjusted to 0x%x-0x%x\n",
> + base, base + (u32) dev_priv->gtt.stolen_size - 1);
> + }
> + }
> +
> +
> /* Verify that nothing else uses this physical address. Stolen
> * memory should be reserved by the BIOS and hidden from the
> * kernel. So if the region is already marked as busy, something
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index 247be2a..619924b 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -978,6 +978,9 @@ enum punit_power_well {
> /*
> * Instruction and interrupt control regs
> */
> +#define PGTBL_CTL 0x02020
> +#define PGTBL_ADDRESS_LO_MASK 0xfffff000 /* bits [31:12] */
> +#define PGTBL_ADDRESS_HI_MASK 0x000000f0 /* bits [35:32] (gen4) */
> #define PGTBL_ER 0x02024
> #define RENDER_RING_BASE 0x02000
> #define BSD_RING_BASE 0x04000
> --
> 1.8.5.5
>
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--
Jani Nikula, Intel Open Source Technology Center
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