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, 23 insertions, 22 deletions

diff --git a/drivers/gpu/drm/i915/intel_dsi.c b/drivers/gpu/drm/i915/intel_dsi.c
index 170ae6f..efb5a27 100644
--- a/drivers/gpu/drm/i915/intel_dsi.c
+++ b/drivers/gpu/drm/i915/intel_dsi.c
@@ -60,7 +60,8 @@ static void wait_for_dsi_fifo_empty(struct intel_dsi *intel_dsi, enum port port)
 		DRM_ERROR("DPI FIFOs are not empty\n");
 }
 
-static void write_data(struct drm_i915_private *dev_priv, u32 reg,
+static void write_data(struct drm_i915_private *dev_priv,
+		       i915_reg_t reg,
 		       const u8 *data, u32 len)
 {
 	u32 i, j;
@@ -75,7 +76,8 @@ static void write_data(struct drm_i915_private *dev_priv, u32 reg,
 	}
 }
 
-static void read_data(struct drm_i915_private *dev_priv, u32 reg,
+static void read_data(struct drm_i915_private *dev_priv,
+		      i915_reg_t reg,
 		      u8 *data, u32 len)
 {
 	u32 i, j;
@@ -98,7 +100,8 @@ static ssize_t intel_dsi_host_transfer(struct mipi_dsi_host *host,
 	struct mipi_dsi_packet packet;
 	ssize_t ret;
 	const u8 *header, *data;
-	u32 data_reg, data_mask, ctrl_reg, ctrl_mask;
+	i915_reg_t data_reg, ctrl_reg;
+	u32 data_mask, ctrl_mask;
 
 	ret = mipi_dsi_create_packet(&packet, msg);
 	if (ret < 0)
@@ -377,10 +380,10 @@ static void intel_dsi_port_enable(struct intel_encoder *encoder)
 	struct intel_crtc *intel_crtc = to_intel_crtc(encoder->base.crtc);
 	struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
 	enum port port;
-	u32 temp;
-	u32 port_ctrl;
 
 	if (intel_dsi->dual_link == DSI_DUAL_LINK_FRONT_BACK) {
+		u32 temp;
+
 		temp = I915_READ(VLV_CHICKEN_3);
 		temp &= ~PIXEL_OVERLAP_CNT_MASK |
 					intel_dsi->pixel_overlap <<
@@ -389,8 +392,9 @@ static void intel_dsi_port_enable(struct intel_encoder *encoder)
 	}
 
 	for_each_dsi_port(port, intel_dsi->ports) {
-		port_ctrl = IS_BROXTON(dev) ? BXT_MIPI_PORT_CTRL(port) :
-						MIPI_PORT_CTRL(port);
+		i915_reg_t port_ctrl = IS_BROXTON(dev) ?
+			BXT_MIPI_PORT_CTRL(port) : MIPI_PORT_CTRL(port);
+		u32 temp;
 
 		temp = I915_READ(port_ctrl);
 
@@ -416,13 +420,13 @@ static void intel_dsi_port_disable(struct intel_encoder *encoder)
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
 	enum port port;
-	u32 temp;
-	u32 port_ctrl;
 
 	for_each_dsi_port(port, intel_dsi->ports) {
+		i915_reg_t port_ctrl = IS_BROXTON(dev) ?
+			BXT_MIPI_PORT_CTRL(port) : MIPI_PORT_CTRL(port);
+		u32 temp;
+
 		/* de-assert ip_tg_enable signal */
-		port_ctrl = IS_BROXTON(dev) ? BXT_MIPI_PORT_CTRL(port) :
-						MIPI_PORT_CTRL(port);
 		temp = I915_READ(port_ctrl);
 		I915_WRITE(port_ctrl, temp & ~DPI_ENABLE);
 		POSTING_READ(port_ctrl);
@@ -580,11 +584,13 @@ static void intel_dsi_clear_device_ready(struct intel_encoder *encoder)
 	struct drm_i915_private *dev_priv = encoder->base.dev->dev_private;
 	struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
 	enum port port;
-	u32 val;
-	u32 port_ctrl = 0;
 
 	DRM_DEBUG_KMS("\n");
 	for_each_dsi_port(port, intel_dsi->ports) {
+		/* Common bit for both MIPI Port A & MIPI Port C on VLV/CHV */
+		i915_reg_t port_ctrl = IS_BROXTON(dev) ?
+			BXT_MIPI_PORT_CTRL(port) : MIPI_PORT_CTRL(PORT_A);
+		u32 val;
 
 		I915_WRITE(MIPI_DEVICE_READY(port), DEVICE_READY |
 							ULPS_STATE_ENTER);
@@ -598,12 +604,6 @@ static void intel_dsi_clear_device_ready(struct intel_encoder *encoder)
 							ULPS_STATE_ENTER);
 		usleep_range(2000, 2500);
 
-		if (IS_BROXTON(dev))
-			port_ctrl = BXT_MIPI_PORT_CTRL(port);
-		else if (IS_VALLEYVIEW(dev))
-			/* Common bit for both MIPI Port A & MIPI Port C */
-			port_ctrl = MIPI_PORT_CTRL(PORT_A);
-
 		/* Wait till Clock lanes are in LP-00 state for MIPI Port A
 		 * only. MIPI Port C has no similar bit for checking
 		 */
@@ -656,7 +656,6 @@ static bool intel_dsi_get_hw_state(struct intel_encoder *encoder,
 	struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
 	struct drm_device *dev = encoder->base.dev;
 	enum intel_display_power_domain power_domain;
-	u32 dpi_enabled, func, ctrl_reg;
 	enum port port;
 
 	DRM_DEBUG_KMS("\n");
@@ -667,9 +666,11 @@ static bool intel_dsi_get_hw_state(struct intel_encoder *encoder,
 
 	/* XXX: this only works for one DSI output */
 	for_each_dsi_port(port, intel_dsi->ports) {
+		i915_reg_t ctrl_reg = IS_BROXTON(dev) ?
+			BXT_MIPI_PORT_CTRL(port) : MIPI_PORT_CTRL(port);
+		u32 dpi_enabled, func;
+
 		func = I915_READ(MIPI_DSI_FUNC_PRG(port));
-		ctrl_reg = IS_BROXTON(dev) ? BXT_MIPI_PORT_CTRL(port) :
-						MIPI_PORT_CTRL(port);
 		dpi_enabled = I915_READ(ctrl_reg) & DPI_ENABLE;
 
 		/* Due to some hardware limitations on BYT, MIPI Port C DPI