soc: qcom: socinfo: handle 'too new' format versions gracefully

Presently, if the bootchain updates the socinfo format version,
a corresponding change to the Linux soconfi driver must first be
made to avoid an "Unknown format found" error.

Avoid this by taking advantage of the fact that new format versions
with the same major version number are defined to be backward-
compatible with older formats having the same major number.

Change-Id: I985a46eeefaacd3425bbc17f72fe09b86264f8b1
Signed-off-by: Matt Wagantall <mattw@codeaurora.org>

1 files changed, 43 insertions, 23 deletions

diff --git a/drivers/soc/qcom/socinfo.c b/drivers/soc/qcom/socinfo.c
index ee8dadbc49d5..182eeb4ab2d5 100644
--- a/drivers/soc/qcom/socinfo.c
+++ b/drivers/soc/qcom/socinfo.c
@@ -220,6 +220,9 @@ static union {
 	struct socinfo_v0_11 v0_11;
 } *socinfo;
 
+/* max socinfo format version supported */
+#define MAX_SOCINFO_FORMAT SOCINFO_VERSION(0, 11)
+
 static struct msm_soc_info cpu_of_id[] = {
 
 	/* 7x01 IDs */
@@ -534,6 +537,7 @@ static struct msm_soc_info cpu_of_id[] = {
 
 static enum msm_cpu cur_cpu;
 static int current_image;
+static uint32_t socinfo_format;
 
 static struct socinfo_v0_1 dummy_socinfo = {
 	.format = SOCINFO_VERSION(0, 1),
@@ -588,7 +592,7 @@ err_path:
 uint32_t socinfo_get_raw_id(void)
 {
 	return socinfo ?
-		(socinfo->v0_1.format >= SOCINFO_VERSION(0, 2) ?
+		(socinfo_format >= SOCINFO_VERSION(0, 2) ?
 			socinfo->v0_2.raw_id : 0)
 		: 0;
 }
@@ -596,7 +600,7 @@ uint32_t socinfo_get_raw_id(void)
 uint32_t socinfo_get_raw_version(void)
 {
 	return socinfo ?
-		(socinfo->v0_1.format >= SOCINFO_VERSION(0, 2) ?
+		(socinfo_format >= SOCINFO_VERSION(0, 2) ?
 			socinfo->v0_2.raw_version : 0)
 		: 0;
 }
@@ -604,7 +608,7 @@ uint32_t socinfo_get_raw_version(void)
 uint32_t socinfo_get_platform_type(void)
 {
 	return socinfo ?
-		(socinfo->v0_1.format >= SOCINFO_VERSION(0, 3) ?
+		(socinfo_format >= SOCINFO_VERSION(0, 3) ?
 			socinfo->v0_3.hw_platform : 0)
 		: 0;
 }
@@ -613,7 +617,7 @@ uint32_t socinfo_get_platform_type(void)
 uint32_t socinfo_get_platform_version(void)
 {
 	return socinfo ?
-		(socinfo->v0_1.format >= SOCINFO_VERSION(0, 4) ?
+		(socinfo_format >= SOCINFO_VERSION(0, 4) ?
 			socinfo->v0_4.platform_version : 0)
 		: 0;
 }
@@ -623,7 +627,7 @@ uint32_t socinfo_get_platform_version(void)
 static uint32_t socinfo_get_accessory_chip(void)
 {
 	return socinfo ?
-		(socinfo->v0_1.format >= SOCINFO_VERSION(0, 5) ?
+		(socinfo_format >= SOCINFO_VERSION(0, 5) ?
 			socinfo->v0_5.accessory_chip : 0)
 		: 0;
 }
@@ -631,7 +635,7 @@ static uint32_t socinfo_get_accessory_chip(void)
 uint32_t socinfo_get_platform_subtype(void)
 {
 	return socinfo ?
-		(socinfo->v0_1.format >= SOCINFO_VERSION(0, 6) ?
+		(socinfo_format >= SOCINFO_VERSION(0, 6) ?
 			socinfo->v0_6.hw_platform_subtype : 0)
 		: 0;
 }
@@ -639,7 +643,7 @@ uint32_t socinfo_get_platform_subtype(void)
 static uint32_t socinfo_get_foundry_id(void)
 {
 	return socinfo ?
-		(socinfo->v0_1.format >= SOCINFO_VERSION(0, 9) ?
+		(socinfo_format >= SOCINFO_VERSION(0, 9) ?
 			socinfo->v0_9.foundry_id : 0)
 		: 0;
 }
@@ -647,7 +651,7 @@ static uint32_t socinfo_get_foundry_id(void)
 static uint32_t socinfo_get_serial_number(void)
 {
 	return socinfo ?
-		(socinfo->v0_1.format >= SOCINFO_VERSION(0, 10) ?
+		(socinfo_format >= SOCINFO_VERSION(0, 10) ?
 			socinfo->v0_10.serial_number : 0)
 		: 0;
 }
@@ -655,7 +659,7 @@ static uint32_t socinfo_get_serial_number(void)
 enum pmic_model socinfo_get_pmic_model(void)
 {
 	return socinfo ?
-		(socinfo->v0_1.format >= SOCINFO_VERSION(0, 7) ?
+		(socinfo_format >= SOCINFO_VERSION(0, 7) ?
 			socinfo->v0_7.pmic_model : PMIC_MODEL_UNKNOWN)
 		: PMIC_MODEL_UNKNOWN;
 }
@@ -663,7 +667,7 @@ enum pmic_model socinfo_get_pmic_model(void)
 uint32_t socinfo_get_pmic_die_revision(void)
 {
 	return socinfo ?
-		(socinfo->v0_1.format >= SOCINFO_VERSION(0, 7) ?
+		(socinfo_format >= SOCINFO_VERSION(0, 7) ?
 			socinfo->v0_7.pmic_die_revision : 0)
 		: 0;
 }
@@ -674,11 +678,6 @@ static char *socinfo_get_image_version_base_address(void)
 				SMEM_IMAGE_VERSION_SIZE, 0, SMEM_ANY_HOST_FLAG);
 }
 
-static uint32_t socinfo_get_format(void)
-{
-	return socinfo ? socinfo->v0_1.format : 0;
-}
-
 enum msm_cpu socinfo_get_msm_cpu(void)
 {
 	return cur_cpu;
@@ -1089,15 +1088,13 @@ static void * __init setup_dummy_socinfo(void)
 
 static void __init populate_soc_sysfs_files(struct device *msm_soc_device)
 {
-	uint32_t legacy_format = socinfo_get_format();
-
 	device_create_file(msm_soc_device, &msm_soc_attr_vendor);
 	device_create_file(msm_soc_device, &image_version);
 	device_create_file(msm_soc_device, &image_variant);
 	device_create_file(msm_soc_device, &image_crm_version);
 	device_create_file(msm_soc_device, &select_image);
 
-	switch (legacy_format) {
+	switch (socinfo_format) {
 	case SOCINFO_VERSION(0, 10):
 		 device_create_file(msm_soc_device,
 					&msm_soc_attr_serial_number);
@@ -1135,8 +1132,8 @@ static void __init populate_soc_sysfs_files(struct device *msm_soc_device)
 		break;
 	default:
 		pr_err("Unknown socinfo format: v%u.%u\n",
-				SOCINFO_VERSION_MAJOR(legacy_format),
-				SOCINFO_VERSION_MINOR(legacy_format));
+				SOCINFO_VERSION_MAJOR(socinfo_format),
+				SOCINFO_VERSION_MINOR(socinfo_format));
 		break;
 	}
 
@@ -1191,12 +1188,12 @@ late_initcall(socinfo_init_sysfs);
 
 static void socinfo_print(void)
 {
-	uint32_t f_maj = SOCINFO_VERSION_MAJOR(socinfo->v0_1.format);
-	uint32_t f_min = SOCINFO_VERSION_MINOR(socinfo->v0_1.format);
+	uint32_t f_maj = SOCINFO_VERSION_MAJOR(socinfo_format);
+	uint32_t f_min = SOCINFO_VERSION_MINOR(socinfo_format);
 	uint32_t v_maj = SOCINFO_VERSION_MAJOR(socinfo->v0_1.version);
 	uint32_t v_min = SOCINFO_VERSION_MINOR(socinfo->v0_1.version);
 
-	switch (socinfo->v0_1.format) {
+	switch (socinfo_format) {
 	case SOCINFO_VERSION(0, 1):
 		pr_info("v%u.%u, id=%u, ver=%u.%u\n",
 			f_maj, f_min, socinfo->v0_1.id, v_maj, v_min);
@@ -1300,6 +1297,27 @@ static void socinfo_print(void)
 	}
 }
 
+static void socinfo_select_format(void)
+{
+	uint32_t f_maj = SOCINFO_VERSION_MAJOR(socinfo->v0_1.format);
+	uint32_t f_min = SOCINFO_VERSION_MINOR(socinfo->v0_1.format);
+
+	if (f_maj != 0) {
+		pr_err("Unsupported format v%u.%u. Falling back to dummy values.\n",
+			f_maj, f_min);
+		socinfo = setup_dummy_socinfo();
+	}
+
+	if (socinfo->v0_1.format > MAX_SOCINFO_FORMAT) {
+		pr_warn("Unsupported format v%u.%u. Falling back to v%u.%u.\n",
+			f_maj, f_min, SOCINFO_VERSION_MAJOR(MAX_SOCINFO_FORMAT),
+			SOCINFO_VERSION_MINOR(MAX_SOCINFO_FORMAT));
+		socinfo_format = MAX_SOCINFO_FORMAT;
+	} else {
+		socinfo_format = socinfo->v0_1.format;
+	}
+}
+
 int __init socinfo_init(void)
 {
 	static bool socinfo_init_done;
@@ -1315,6 +1333,8 @@ int __init socinfo_init(void)
 		socinfo = setup_dummy_socinfo();
 	}
 
+	socinfo_select_format();
+
 	WARN(!socinfo_get_id(), "Unknown SOC ID!\n");
 
 	if (socinfo_get_id() >= ARRAY_SIZE(cpu_of_id))