soc: qcom: smem: Add a feature code getter

Recent (SM8550+ ish) Qualcomm SoCs have a new mechanism for precisely
identifying the specific SKU and the precise speed bin (in the general
meaning of this word, anyway): a pair of values called Product Code
and Feature Code.

Based on this information, we can deduce the available frequencies for
things such as Adreno. In the case of Adreno specifically, Pcode is
useless for non-prototype SoCs.

Introduce a getter for the feature code and export it.

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Link: https://lore.kernel.org/r/20240605-topic-smem_speedbin-v2-2-8989d7e3d176@linaro.org
Signed-off-by: Bjorn Andersson <andersson@kernel.org>

drivers/soc/qcom/smem.c

@@ -795,6 +795,39 @@ int qcom_smem_get_soc_id(u32 *id)
 }
 EXPORT_SYMBOL_GPL(qcom_smem_get_soc_id);
 
+/**
+ * qcom_smem_get_feature_code() - return the feature code
+ * @code: On success, return the feature code here.
+ *
+ * Look up the feature code identifier from SMEM and return it.
+ *
+ * Return: 0 on success, negative errno on failure.
+ */
+int qcom_smem_get_feature_code(u32 *code)
+{
+	struct socinfo *info;
+	u32 raw_code;
+
+	info = qcom_smem_get(QCOM_SMEM_HOST_ANY, SMEM_HW_SW_BUILD_ID, NULL);
+	if (IS_ERR(info))
+		return PTR_ERR(info);
+
+	/* This only makes sense for socinfo >= 16 */
+	if (__le32_to_cpu(info->fmt) < SOCINFO_VERSION(0, 16))
+		return -EOPNOTSUPP;
+
+	raw_code = __le32_to_cpu(info->feature_code);
+
+	/* Ensure the value makes sense */
+	if (raw_code > SOCINFO_FC_INT_MAX)
+		raw_code = SOCINFO_FC_UNKNOWN;
+
+	*code = raw_code;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(qcom_smem_get_feature_code);
+
 static int qcom_smem_get_sbl_version(struct qcom_smem *smem)
 {
 	struct smem_header *header;

include/linux/soc/qcom/smem.h

@@ -13,5 +13,6 @@ int qcom_smem_get_free_space(unsigned host);
 phys_addr_t qcom_smem_virt_to_phys(void *p);
 
 int qcom_smem_get_soc_id(u32 *id);
+int qcom_smem_get_feature_code(u32 *code);
 
 #endif

include/linux/soc/qcom/socinfo.h

@@ -3,6 +3,8 @@
 #ifndef __QCOM_SOCINFO_H__
 #define __QCOM_SOCINFO_H__
 
+#include <linux/types.h>
+
 /*
  * SMEM item id, used to acquire handles to respective
  * SMEM region.
@@ -82,4 +84,28 @@ struct socinfo {
 	__le32 boot_core;
 };
 
+/* Internal feature codes */
+enum qcom_socinfo_feature_code {
+	/* External feature codes */
+	SOCINFO_FC_UNKNOWN = 0x0,
+	SOCINFO_FC_AA,
+	SOCINFO_FC_AB,
+	SOCINFO_FC_AC,
+	SOCINFO_FC_AD,
+	SOCINFO_FC_AE,
+	SOCINFO_FC_AF,
+	SOCINFO_FC_AG,
+	SOCINFO_FC_AH,
+};
+
+/* Internal feature codes */
+/* Valid values: 0 <= n <= 0xf */
+#define SOCINFO_FC_Yn(n)		(0xf1 + (n))
+#define SOCINFO_FC_INT_MAX		SOCINFO_FC_Yn(0xf)
+
+/* Product codes */
+#define SOCINFO_PC_UNKNOWN		0
+#define SOCINFO_PCn(n)			((n) + 1)
+#define SOCINFO_PC_RESERVE		(BIT(31) - 1)
+
 #endif