drm/i915: add Punit read/write routines for VLV v2

Slightly different than other platforms.

v2 [Jani]: Fix IOSF_BYTE_ENABLES_SHIFT shift. Use common routine.
v3: drop turbo defines from this patch (Ville)
    use PCI_DEVFN(2,0) instead of open coding (Ville)
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
[danvet: Add checkpatch bikeshed about missing space.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_drv.h

@@ -1863,6 +1863,8 @@ int __gen6_gt_wait_for_fifo(struct drm_i915_private *dev_priv);
 
 int sandybridge_pcode_read(struct drm_i915_private *dev_priv, u8 mbox, u32 *val);
 int sandybridge_pcode_write(struct drm_i915_private *dev_priv, u8 mbox, u32 val);
+int valleyview_punit_read(struct drm_i915_private *dev_priv, u8 addr, u32 *val);
+int valleyview_punit_write(struct drm_i915_private *dev_priv, u8 addr, u32 val);
 
 #define __i915_read(x, y) \
 	u##x i915_read##x(struct drm_i915_private *dev_priv, u32 reg);

drivers/gpu/drm/i915/i915_reg.h

@@ -4381,6 +4381,20 @@
 #define GEN6_PCODE_DATA				0x138128
 #define   GEN6_PCODE_FREQ_IA_RATIO_SHIFT	8
 
+#define VLV_IOSF_DOORBELL_REQ			0x182100
+#define   IOSF_DEVFN_SHIFT			24
+#define   IOSF_OPCODE_SHIFT			16
+#define   IOSF_PORT_SHIFT			8
+#define   IOSF_BYTE_ENABLES_SHIFT		4
+#define   IOSF_BAR_SHIFT			1
+#define   IOSF_SB_BUSY				(1<<0)
+#define   IOSF_PORT_PUNIT			0x4
+#define VLV_IOSF_DATA				0x182104
+#define VLV_IOSF_ADDR				0x182108
+
+#define PUNIT_OPCODE_REG_READ			6
+#define PUNIT_OPCODE_REG_WRITE			7
+
 #define GEN6_GT_CORE_STATUS		0x138060
 #define   GEN6_CORE_CPD_STATE_MASK	(7<<4)
 #define   GEN6_RCn_MASK			7

drivers/gpu/drm/i915/intel_pm.c

@@ -4536,3 +4536,56 @@ int sandybridge_pcode_write(struct drm_i915_private *dev_priv, u8 mbox, u32 val)
 
 	return 0;
 }
+
+static int vlv_punit_rw(struct drm_i915_private *dev_priv, u8 opcode,
+			u8 addr, u32 *val)
+{
+	u32 cmd, devfn, port, be, bar;
+
+	bar = 0;
+	be = 0xf;
+	port = IOSF_PORT_PUNIT;
+	devfn = PCI_DEVFN(2, 0);
+
+	cmd = (devfn << IOSF_DEVFN_SHIFT) | (opcode << IOSF_OPCODE_SHIFT) |
+		(port << IOSF_PORT_SHIFT) | (be << IOSF_BYTE_ENABLES_SHIFT) |
+		(bar << IOSF_BAR_SHIFT);
+
+	WARN_ON(!mutex_is_locked(&dev_priv->rps.hw_lock));
+
+	if (I915_READ(VLV_IOSF_DOORBELL_REQ) & IOSF_SB_BUSY) {
+		DRM_DEBUG_DRIVER("warning: pcode (%s) mailbox access failed\n",
+				 opcode == PUNIT_OPCODE_REG_READ ?
+				 "read" : "write");
+		return -EAGAIN;
+	}
+
+	I915_WRITE(VLV_IOSF_ADDR, addr);
+	if (opcode == PUNIT_OPCODE_REG_WRITE)
+		I915_WRITE(VLV_IOSF_DATA, *val);
+	I915_WRITE(VLV_IOSF_DOORBELL_REQ, cmd);
+
+	if (wait_for((I915_READ(VLV_IOSF_DOORBELL_REQ) & IOSF_SB_BUSY) == 0,
+		     500)) {
+		DRM_ERROR("timeout waiting for pcode %s (%d) to finish\n",
+			  opcode == PUNIT_OPCODE_REG_READ ? "read" : "write",
+			  addr);
+		return -ETIMEDOUT;
+	}
+
+	if (opcode == PUNIT_OPCODE_REG_READ)
+		*val = I915_READ(VLV_IOSF_DATA);
+	I915_WRITE(VLV_IOSF_DATA, 0);
+
+	return 0;
+}
+
+int valleyview_punit_read(struct drm_i915_private *dev_priv, u8 addr, u32 *val)
+{
+	return vlv_punit_rw(dev_priv, PUNIT_OPCODE_REG_READ, addr, val);
+}
+
+int valleyview_punit_write(struct drm_i915_private *dev_priv, u8 addr, u32 val)
+{
+	return vlv_punit_rw(dev_priv, PUNIT_OPCODE_REG_WRITE, addr, &val);
+}