drm/i915/pcode: Add a couple of pcode helpers

Some dGfx pcode commands take additional sub-commands and parameters. Add a
couple of helpers to help formatting these commands to improve code
readability.

v2: Fixed commit author (Rodrigo)
v3: Function rename and convert to new uncore interface for pcode functions
    Remove unnecessary #define's (Andi)
v4: Another function rename

Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Signed-off-by: Dale B Stimson <dale.b.stimson@intel.com>
Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220519085732.1276255-3-tvrtko.ursulin@linux.intel.com

drivers/gpu/drm/i915/i915_reg.h

@@ -6674,6 +6674,9 @@
 
 #define GEN6_PCODE_MAILBOX			_MMIO(0x138124)
 #define   GEN6_PCODE_READY			(1 << 31)
+#define   GEN6_PCODE_MB_PARAM2			REG_GENMASK(23, 16)
+#define   GEN6_PCODE_MB_PARAM1			REG_GENMASK(15, 8)
+#define   GEN6_PCODE_MB_COMMAND			REG_GENMASK(7, 0)
 #define   GEN6_PCODE_ERROR_MASK			0xFF
 #define     GEN6_PCODE_SUCCESS			0x0
 #define     GEN6_PCODE_ILLEGAL_CMD		0x1

drivers/gpu/drm/i915/intel_pcode.c

@@ -214,3 +214,35 @@ int intel_pcode_init(struct intel_uncore *uncore)
 				 DG1_UNCORE_INIT_STATUS_COMPLETE,
 				 DG1_UNCORE_INIT_STATUS_COMPLETE, 180000);
 }
+
+int snb_pcode_read_p(struct intel_uncore *uncore, u32 mbcmd, u32 p1, u32 p2, u32 *val)
+{
+	intel_wakeref_t wakeref;
+	u32 mbox;
+	int err;
+
+	mbox = REG_FIELD_PREP(GEN6_PCODE_MB_COMMAND, mbcmd)
+		| REG_FIELD_PREP(GEN6_PCODE_MB_PARAM1, p1)
+		| REG_FIELD_PREP(GEN6_PCODE_MB_PARAM2, p2);
+
+	with_intel_runtime_pm(uncore->rpm, wakeref)
+		err = snb_pcode_read(uncore, mbox, val, NULL);
+
+	return err;
+}
+
+int snb_pcode_write_p(struct intel_uncore *uncore, u32 mbcmd, u32 p1, u32 p2, u32 val)
+{
+	intel_wakeref_t wakeref;
+	u32 mbox;
+	int err;
+
+	mbox = REG_FIELD_PREP(GEN6_PCODE_MB_COMMAND, mbcmd)
+		| REG_FIELD_PREP(GEN6_PCODE_MB_PARAM1, p1)
+		| REG_FIELD_PREP(GEN6_PCODE_MB_PARAM2, p2);
+
+	with_intel_runtime_pm(uncore->rpm, wakeref)
+		err = snb_pcode_write(uncore, mbox, val);
+
+	return err;
+}

drivers/gpu/drm/i915/intel_pcode.h

@@ -21,4 +21,10 @@ int skl_pcode_request(struct intel_uncore *uncore, u32 mbox, u32 request,
 
 int intel_pcode_init(struct intel_uncore *uncore);
 
+/*
+ * Helpers for dGfx PCODE mailbox command formatting
+ */
+int snb_pcode_read_p(struct intel_uncore *uncore, u32 mbcmd, u32 p1, u32 p2, u32 *val);
+int snb_pcode_write_p(struct intel_uncore *uncore, u32 mbcmd, u32 p1, u32 p2, u32 val);
+
 #endif /* _INTEL_PCODE_H */