drm/i915/uncore: Convert gen6/gen7 read operations to fwtable

On gen6-gen8 (except vlv/chv) we don't use a forcewake lookup table; we
simply check whether the register offset is < 0x40000, and return
FORCEWAKE_RENDER if it is.  To prepare for upcoming refactoring, let's
define a single-entry forcewake table from [0x0, 0x3ffff] and switch
these platforms over to use the fwtable reader functions.

v2:
 - Drop __gen6_reg_read_fw_domains which is no longer used.  (Tvrtko)

Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210910201030.3436066-2-matthew.d.roper@intel.com

drivers/gpu/drm/i915/intel_uncore.c

@@ -853,16 +853,6 @@ void assert_forcewakes_active(struct intel_uncore *uncore,
 /* We give fast paths for the really cool registers */
 #define NEEDS_FORCE_WAKE(reg) ((reg) < 0x40000)
 
-#define __gen6_reg_read_fw_domains(uncore, offset) \
-({ \
-	enum forcewake_domains __fwd; \
-	if (NEEDS_FORCE_WAKE(offset)) \
-		__fwd = FORCEWAKE_RENDER; \
-	else \
-		__fwd = 0; \
-	__fwd; \
-})
-
 static int fw_range_cmp(u32 offset, const struct intel_forcewake_range *entry)
 {
 	if (offset < entry->start)
@@ -1064,6 +1054,10 @@ gen6_reg_write_fw_domains(struct intel_uncore *uncore, i915_reg_t reg)
 	__fwd; \
 })
 
+static const struct intel_forcewake_range __gen6_fw_ranges[] = {
+	GEN_FW_RANGE(0x0, 0x3ffff, FORCEWAKE_RENDER),
+};
+
 /* *Must* be sorted by offset ranges! See intel_fw_table_check(). */
 static const struct intel_forcewake_range __chv_fw_ranges[] = {
 	GEN_FW_RANGE(0x2000, 0x3fff, FORCEWAKE_RENDER),
@@ -1623,7 +1617,6 @@ __gen_read(func, 64)
 
 __gen_reg_read_funcs(gen11_fwtable);
 __gen_reg_read_funcs(fwtable);
-__gen_reg_read_funcs(gen6);
 
 #undef __gen_reg_read_funcs
 #undef GEN6_READ_FOOTER
@@ -2111,15 +2104,17 @@ static int uncore_forcewake_init(struct intel_uncore *uncore)
 		ASSIGN_WRITE_MMIO_VFUNCS(uncore, fwtable);
 		ASSIGN_READ_MMIO_VFUNCS(uncore, fwtable);
 	} else if (GRAPHICS_VER(i915) == 8) {
+		ASSIGN_FW_DOMAINS_TABLE(uncore, __gen6_fw_ranges);
 		ASSIGN_WRITE_MMIO_VFUNCS(uncore, gen8);
-		ASSIGN_READ_MMIO_VFUNCS(uncore, gen6);
+		ASSIGN_READ_MMIO_VFUNCS(uncore, fwtable);
 	} else if (IS_VALLEYVIEW(i915)) {
 		ASSIGN_FW_DOMAINS_TABLE(uncore, __vlv_fw_ranges);
 		ASSIGN_WRITE_MMIO_VFUNCS(uncore, gen6);
 		ASSIGN_READ_MMIO_VFUNCS(uncore, fwtable);
 	} else if (IS_GRAPHICS_VER(i915, 6, 7)) {
+		ASSIGN_FW_DOMAINS_TABLE(uncore, __gen6_fw_ranges);
 		ASSIGN_WRITE_MMIO_VFUNCS(uncore, gen6);
-		ASSIGN_READ_MMIO_VFUNCS(uncore, gen6);
+		ASSIGN_READ_MMIO_VFUNCS(uncore, fwtable);
 	}
 
 	uncore->pmic_bus_access_nb.notifier_call = i915_pmic_bus_access_notifier;