drm/i915: Type safe register read/write

Make I915_READ and I915_WRITE more type safe by wrapping the register
offset in a struct. This should eliminate most of the fumbles we've had
with misplaced parens.

This only takes care of normal mmio registers. We could extend the idea
to other register types and define each with its own struct. That way
you wouldn't be able to accidentally pass the wrong thing to a specific
register access function.

The gpio_reg setup is probably the ugliest thing left. But I figure I'd
just leave it for now, and wait for some divine inspiration to strike
before making it nice.

As for the generated code, it's actually a bit better sometimes. Eg.
looking at i915_irq_handler(), we can see the following change:
  lea    0x70024(%rdx,%rax,1),%r9d
  mov    $0x1,%edx
- movslq %r9d,%r9
- mov    %r9,%rsi
- mov    %r9,-0x58(%rbp)
- callq  *0xd8(%rbx)
+ mov    %r9d,%esi
+ mov    %r9d,-0x48(%rbp)
 callq  *0xd8(%rbx)

So previously gcc thought the register offset might be signed and
decided to sign extend it, just in case. The rest appears to be
mostly just minor shuffling of instructions.

v2: i915_mmio_reg_{offset,equal,valid}() helpers added
    s/_REG/_MMIO/ in the register defines
    mo more switch statements left to worry about
    ring_emit stuff got sorted in a prep patch
    cmd parser, lrc context and w/a batch buildup also in prep patch
    vgpu stuff cleaned up and moved to a prep patch
    all other unrelated changes split out
v3: Rebased due to BXT DSI/BLC, MOCS, etc.
v4: Rebased due to churn, s/i915_mmio_reg_t/i915_reg_t/

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/1447853606-2751-1-git-send-email-ville.syrjala@linux.intel.com

1 files changed, 15 insertions, 15 deletions

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 8c0e9de9c9af..78f0ac3d1e7f 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -139,7 +139,8 @@ static const u32 hpd_bxt[HPD_NUM_PINS] = {
 /*
  * We should clear IMR at preinstall/uninstall, and just check at postinstall.
  */
-static void gen5_assert_iir_is_zero(struct drm_i915_private *dev_priv, u32 reg)
+static void gen5_assert_iir_is_zero(struct drm_i915_private *dev_priv,
+				    i915_reg_t reg)
 {
 	u32 val = I915_READ(reg);
 
@@ -147,7 +148,7 @@ static void gen5_assert_iir_is_zero(struct drm_i915_private *dev_priv, u32 reg)
 		return;
 
 	WARN(1, "Interrupt register 0x%x is not zero: 0x%08x\n",
-	     reg, val);
+	     i915_mmio_reg_offset(reg), val);
 	I915_WRITE(reg, 0xffffffff);
 	POSTING_READ(reg);
 	I915_WRITE(reg, 0xffffffff);
@@ -283,17 +284,17 @@ void gen5_disable_gt_irq(struct drm_i915_private *dev_priv, uint32_t mask)
 	ilk_update_gt_irq(dev_priv, mask, 0);
 }
 
-static u32 gen6_pm_iir(struct drm_i915_private *dev_priv)
+static i915_reg_t gen6_pm_iir(struct drm_i915_private *dev_priv)
 {
 	return INTEL_INFO(dev_priv)->gen >= 8 ? GEN8_GT_IIR(2) : GEN6_PMIIR;
 }
 
-static u32 gen6_pm_imr(struct drm_i915_private *dev_priv)
+static i915_reg_t gen6_pm_imr(struct drm_i915_private *dev_priv)
 {
 	return INTEL_INFO(dev_priv)->gen >= 8 ? GEN8_GT_IMR(2) : GEN6_PMIMR;
 }
 
-static u32 gen6_pm_ier(struct drm_i915_private *dev_priv)
+static i915_reg_t gen6_pm_ier(struct drm_i915_private *dev_priv)
 {
 	return INTEL_INFO(dev_priv)->gen >= 8 ? GEN8_GT_IER(2) : GEN6_PMIER;
 }
@@ -350,7 +351,7 @@ void gen6_disable_pm_irq(struct drm_i915_private *dev_priv, uint32_t mask)
 void gen6_reset_rps_interrupts(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
-	uint32_t reg = gen6_pm_iir(dev_priv);
+	i915_reg_t reg = gen6_pm_iir(dev_priv);
 
 	spin_lock_irq(&dev_priv->irq_lock);
 	I915_WRITE(reg, dev_priv->pm_rps_events);
@@ -477,7 +478,7 @@ static void
 __i915_enable_pipestat(struct drm_i915_private *dev_priv, enum pipe pipe,
 		       u32 enable_mask, u32 status_mask)
 {
-	u32 reg = PIPESTAT(pipe);
+	i915_reg_t reg = PIPESTAT(pipe);
 	u32 pipestat = I915_READ(reg) & PIPESTAT_INT_ENABLE_MASK;
 
 	assert_spin_locked(&dev_priv->irq_lock);
@@ -504,7 +505,7 @@ static void
 __i915_disable_pipestat(struct drm_i915_private *dev_priv, enum pipe pipe,
 		        u32 enable_mask, u32 status_mask)
 {
-	u32 reg = PIPESTAT(pipe);
+	i915_reg_t reg = PIPESTAT(pipe);
 	u32 pipestat = I915_READ(reg) & PIPESTAT_INT_ENABLE_MASK;
 
 	assert_spin_locked(&dev_priv->irq_lock);
@@ -665,8 +666,7 @@ static u32 i8xx_get_vblank_counter(struct drm_device *dev, int pipe)
 static u32 i915_get_vblank_counter(struct drm_device *dev, int pipe)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
-	unsigned long high_frame;
-	unsigned long low_frame;
+	i915_reg_t high_frame, low_frame;
 	u32 high1, high2, low, pixel, vbl_start, hsync_start, htotal;
 	struct intel_crtc *intel_crtc =
 		to_intel_crtc(dev_priv->pipe_to_crtc_mapping[pipe]);
@@ -1186,7 +1186,7 @@ static void ivybridge_parity_work(struct work_struct *work)
 	POSTING_READ(GEN7_MISCCPCTL);
 
 	while ((slice = ffs(dev_priv->l3_parity.which_slice)) != 0) {
-		u32 reg;
+		i915_reg_t reg;
 
 		slice--;
 		if (WARN_ON_ONCE(slice >= NUM_L3_SLICES(dev_priv->dev)))
@@ -1622,7 +1622,7 @@ static void valleyview_pipestat_irq_handler(struct drm_device *dev, u32 iir)
 
 	spin_lock(&dev_priv->irq_lock);
 	for_each_pipe(dev_priv, pipe) {
-		int reg;
+		i915_reg_t reg;
 		u32 mask, iir_bit = 0;
 
 		/*
@@ -3870,7 +3870,7 @@ static irqreturn_t i8xx_irq_handler(int irq, void *arg)
 			DRM_DEBUG("Command parser error, iir 0x%08x\n", iir);
 
 		for_each_pipe(dev_priv, pipe) {
-			int reg = PIPESTAT(pipe);
+			i915_reg_t reg = PIPESTAT(pipe);
 			pipe_stats[pipe] = I915_READ(reg);
 
 			/*
@@ -4051,7 +4051,7 @@ static irqreturn_t i915_irq_handler(int irq, void *arg)
 			DRM_DEBUG("Command parser error, iir 0x%08x\n", iir);
 
 		for_each_pipe(dev_priv, pipe) {
-			int reg = PIPESTAT(pipe);
+			i915_reg_t reg = PIPESTAT(pipe);
 			pipe_stats[pipe] = I915_READ(reg);
 
 			/* Clear the PIPE*STAT regs before the IIR */
@@ -4272,7 +4272,7 @@ static irqreturn_t i965_irq_handler(int irq, void *arg)
 			DRM_DEBUG("Command parser error, iir 0x%08x\n", iir);
 
 		for_each_pipe(dev_priv, pipe) {
-			int reg = PIPESTAT(pipe);
+			i915_reg_t reg = PIPESTAT(pipe);
 			pipe_stats[pipe] = I915_READ(reg);
 
 			/*