lib: Introduce fw_config_get_field

In some cases, fw_config is used for ids like sar_id, sku_id etc.
To avoid calling fw_config_probe over and over, hence provide the
method to return the value then caller can use the switch case
instead of if else statement.

TEST=get fw_config field value on nivviks.
[INFO ]  fw_config get field name=DB_USB, mask=0x3, shift=0, value =0x1

Signed-off-by: Eric Lai <eric_lai@quanta.corp-partner.google.com>
Change-Id: Iae89668e8fe7322d5a4dcbf88a97d7ed36619af5
Reviewed-on: https://review.coreboot.org/c/coreboot/+/70745
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-by: Tim Wawrzynczak <inforichland@gmail.com>

1 files changed, 20 insertions, 0 deletions

diff --git a/src/include/fw_config.h b/src/include/fw_config.h
index 7a8ad30482..04fdf98921 100644
--- a/src/include/fw_config.h
+++ b/src/include/fw_config.h
@@ -24,6 +24,11 @@ struct fw_config {
 	uint64_t value;
 };
 
+struct fw_config_field {
+	const char *field_name;
+	uint64_t mask;
+};
+
 /* Generate a pointer to a compound literal of the fw_config structure. */
 #define FW_CONFIG(__field, __option)	(&(const struct fw_config) {		\
 	.field_name = FW_CONFIG_FIELD_##__field##_NAME,				\
@@ -32,6 +37,11 @@ struct fw_config {
 	.value = FW_CONFIG_FIELD_##__field##_OPTION_##__option##_VALUE		\
 })
 
+#define FW_CONFIG_FIELD(__field) (&(const struct fw_config_field) {		\
+	.field_name = FW_CONFIG_FIELD_##__field##_NAME,				\
+	.mask = FW_CONFIG_FIELD_##__field##_MASK,				\
+})
+
 /**
  * fw_config_get() - Provide firmware configuration value.
  *
@@ -42,6 +52,16 @@ uint64_t fw_config_get(void);
 #if CONFIG(FW_CONFIG)
 
 /**
+ * fw_config_get_field() - Provide firmware configuration field value.
+ * @field: Structure containing field name and mask
+ *
+ * Return 64bit firmware configuration value determined for the system.
+ * Will return UNDEFINED_FW_CONFIG if unprovisioned, caller should treat
+ * as error value for the case.
+ */
+uint64_t fw_config_get_field(const struct fw_config_field *field);
+
+/**
  * fw_config_probe() - Check if field and option matches.
  * @match: Structure containing field and option to probe.
  *