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drm/i915: add support for SBI ops

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With Lynx Point, we need to use SBI to communicate with the display clock
control. This commit adds helper functions to access the registers via
SBI.

v2: de-inline the function and address changes in bits names

v3: protect operations with dpio_lock, increase timeout to 100 for
paranoia sake.

v4: decrease paranoia a bit, as noticed by Chris Wilson

Reviewed-by: Rodrigo Vivi <rodrigo.vivi@gmail.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Eugeni Dodonov <eugeni.dodonov@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This commit is contained in:
Eugeni Dodonov 2012-05-09 15:37:10 -03:00 committed by Daniel Vetter
parent 7d4e146f75
commit a416edefbb
1 changed files with 63 additions and 0 deletions
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63
drivers/gpu/drm/i915/intel_display.c
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@ -1299,6 +1299,69 @@ static void intel_disable_pll(struct drm_i915_private *dev_priv, enum pipe pipe)
POSTING_READ(reg);
}
/* SBI access */
static void
intel_sbi_write(struct drm_i915_private *dev_priv, u16 reg, u32 value)
{
unsigned long flags;
spin_lock_irqsave(&dev_priv->dpio_lock, flags);
if (wait_for((I915_READ(SBI_CTL_STAT) & SBI_READY) == 0,
100)) {
DRM_ERROR("timeout waiting for SBI to become ready\n");
goto out_unlock;
}
I915_WRITE(SBI_ADDR,
(reg << 16));
I915_WRITE(SBI_DATA,
value);
I915_WRITE(SBI_CTL_STAT,
SBI_BUSY |
SBI_CTL_OP_CRWR);
if (wait_for((I915_READ(SBI_CTL_STAT) & (SBI_READY | SBI_RESPONSE_SUCCESS)) == 0,
100)) {
DRM_ERROR("timeout waiting for SBI to complete write transaction\n");
goto out_unlock;
}
out_unlock:
spin_unlock_irqrestore(&dev_priv->dpio_lock, flags);
}
static u32
intel_sbi_read(struct drm_i915_private *dev_priv, u16 reg)
{
unsigned long flags;
u32 value;
spin_lock_irqsave(&dev_priv->dpio_lock, flags);
if (wait_for((I915_READ(SBI_CTL_STAT) & SBI_READY) == 0,
100)) {
DRM_ERROR("timeout waiting for SBI to become ready\n");
goto out_unlock;
}
I915_WRITE(SBI_ADDR,
(reg << 16));
I915_WRITE(SBI_CTL_STAT,
SBI_BUSY |
SBI_CTL_OP_CRRD);
if (wait_for((I915_READ(SBI_CTL_STAT) & (SBI_READY | SBI_RESPONSE_SUCCESS)) == 0,
100)) {
DRM_ERROR("timeout waiting for SBI to complete read transaction\n");
goto out_unlock;
}
value = I915_READ(SBI_DATA);
out_unlock:
spin_unlock_irqrestore(&dev_priv->dpio_lock, flags);
return value;
}
/**
* intel_enable_pch_pll - enable PCH PLL
* @dev_priv: i915 private structure