drm/i915: Sort the shadow register table

Also verify the order at runtime. This was we can start using
binary search on it in a following patch.

v2: Add comment on the sorted array and only check it when
    debug option is enabled.

v3: Use IS_ENABLED. (Chris Wilson)

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> (v1)
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>

diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c
index fbcc303..d7c9b6b 100644 (file)
--- a/drivers/gpu/drm/i915/intel_uncore.c
+++ b/drivers/gpu/drm/i915/intel_uncore.c
@@ -663,16 +663,34 @@ static const struct intel_forcewake_range __vlv_fw_ranges[] = {
        __fwd; \
 })
 
+/* *Must* be sorted by offset! See intel_shadow_table_check(). */
 static const i915_reg_t gen8_shadowed_regs[] = {
-       GEN6_RPNSWREQ,
-       GEN6_RC_VIDEO_FREQ,
-       RING_TAIL(RENDER_RING_BASE),
-       RING_TAIL(GEN6_BSD_RING_BASE),
-       RING_TAIL(VEBOX_RING_BASE),
-       RING_TAIL(BLT_RING_BASE),
+       RING_TAIL(RENDER_RING_BASE),    /* 0x2000 (base) */
+       GEN6_RPNSWREQ,                  /* 0xA008 */
+       GEN6_RC_VIDEO_FREQ,             /* 0xA00C */
+       RING_TAIL(GEN6_BSD_RING_BASE),  /* 0x12000 (base) */
+       RING_TAIL(VEBOX_RING_BASE),     /* 0x1a000 (base) */
+       RING_TAIL(BLT_RING_BASE),       /* 0x22000 (base) */
        /* TODO: Other registers are not yet used */
 };
 
+static void intel_shadow_table_check(void)
+{
+       const i915_reg_t *reg = gen8_shadowed_regs;
+       s32 prev;
+       u32 offset;
+       unsigned int i;
+
+       if (!IS_ENABLED(CONFIG_DRM_I915_DEBUG))
+               return;
+
+       for (i = 0, prev = -1; i < ARRAY_SIZE(gen8_shadowed_regs); i++, reg++) {
+               offset = i915_mmio_reg_offset(*reg);
+               WARN_ON_ONCE(prev >= (s32)offset);
+               prev = offset;
+       }
+}
+
 static bool is_gen8_shadowed(u32 offset)
 {
        int i;
@@ -1283,6 +1301,8 @@ void intel_uncore_init(struct drm_i915_private *dev_priv)
        }
 
        intel_fw_table_check(dev_priv);
+       if (INTEL_GEN(dev_priv) >= 8)
+               intel_shadow_table_check();
 
        if (intel_vgpu_active(dev_priv)) {
                ASSIGN_WRITE_MMIO_VFUNCS(vgpu);