soc/intel/xeon_sp: Introduce soc_cpu_is_enabled

Add a function to check if the CPU placed at the specified socket was
found usable during QPI init. This is useful for multi-socket
platforms were a CPU is missing or has been disabled due to an error.

Change-Id: I135968fcc905928b9bc6511e3ddbd7d12bad0096
Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/76556
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>

src/soc/intel/xeon_sp/include/soc/util.h

@@ -13,6 +13,7 @@ msr_t read_msr_ppin(void);
 int get_platform_thread_count(void);
 const IIO_UDS *get_iio_uds(void);
 unsigned int soc_get_num_cpus(void);
+bool soc_cpu_is_enabled(const size_t idx);
 void set_bios_init_completion(void);
 uint8_t soc_get_iio_ioapicid(int socket, int stack);
 

src/soc/intel/xeon_sp/spr/soc_acpi.c

@@ -394,7 +394,7 @@ void uncore_inject_dsdt(const struct device *device)
 			const STACK_RES *ri =
 				&hob->PlatformData.IIO_resource[socket].StackRes[stack];
 
-			stack_enabled = hob->PlatformData.IIO_resource[socket].Valid &&
+			stack_enabled = soc_cpu_is_enabled(socket) &&
 					ri->Personality < TYPE_RESERVED;
 
 			printk(BIOS_DEBUG, "%s processing socket: %d, stack: %d, type: %d\n",

src/soc/intel/xeon_sp/util.c

@@ -118,6 +118,18 @@ void get_iiostack_info(struct iiostack_resource *info)
 	}
 }
 
+/*
+ * Returns true if the CPU in the specified socket was found
+ * during QPI init, false otherwise.
+ */
+bool soc_cpu_is_enabled(const size_t idx)
+{
+	const IIO_UDS *hob = get_iio_uds();
+	assert(idx < CONFIG_MAX_SOCKET);
+
+	return hob->PlatformData.IIO_resource[idx].Valid;
+}
+
 unsigned int soc_get_num_cpus(void)
 {
 	/* The FSP IIO UDS HOB has field numCpus, it is actually socket count */