[M] Change in coreboot[main]: soc/amd/common/psp_smi_flash: add find_psp_spi_flash_device_region

[Felix Held (Code Review)]

Attention is currently required from: Fred Reitberger, Jason Glenesk, Matt DeVillier, ritul guru.

Hello ritul guru,

I'd like you to do a code review.
Please visit

https://review.coreboot.org/c/coreboot/+/83774?usp=email

to review the following change.

Change subject: soc/amd/common/psp_smi_flash: add find_psp_spi_flash_device_region
......................................................................

soc/amd/common/psp_smi_flash: add find_psp_spi_flash_device_region

Add 'find_psp_spi_flash_device_region' to get a pointer to the spi_flash
struct of the SPI flash used in the system and the region_device struct
for the target FMAP region specified by the target NV ID from the PSP
to x86 mailbox command. In order to have small patches, the newly added
static 'find_psp_spi_flash_device_region' function is marked as inline;
that inline will be removed in a following patch that calls this new
function.

This patch is a slightly reworked version of parts of CB:65523.

Document #55758 Rev. 2.04 was used as a reference.

Test=When selecting SOC_AMD_COMMON_BLOCK_PSP_SMI, Mandolin still builds

Signed-off-by: Felix Held 
Signed-off-by: Ritul Guru 
Change-Id: I64b8fba2392de46ecd4c786cef0d5b6acdbd865a
---
M src/soc/amd/common/block/psp/psp_smi_flash.c
1 file changed, 67 insertions(+), 0 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/74/83774/1

diff --git a/src/soc/amd/common/block/psp/psp_smi_flash.c b/src/soc/amd/common/block/psp/psp_smi_flash.c
index f1b9d85..4c83fcd 100644
--- a/src/soc/amd/common/block/psp/psp_smi_flash.c
+++ b/src/soc/amd/common/block/psp/psp_smi_flash.c
@@ -1,7 +1,11 @@
 /* SPDX-License-Identifier: GPL-2.0-only */

+#include <boot_device.h>
+#include <commonlib/region.h>
 #include <console/console.h>
 #include <device/mmio.h>
+#include <fmap.h>
+#include <spi_flash.h>
 #include <types.h>
 #include "psp_def.h"

@@ -67,6 +71,69 @@
    return is_valid_psp_spi_id(read64(&cmd_buf->req.target_nv_id));
 }

+static const char *id_to_region_name(u64 target_nv_id)
+{
+	switch (target_nv_id) {
+	case SMI_TARGET_NVRAM:
+		return "PSP_NVRAM";
+	case SMI_TARGET_RPMC_NVRAM:
+		return "PSP_RPMC_NVRAM";
+	}
+	return NULL;
+}
+
+/*
+ * Do not cache the location to cope with flash changing underneath (e.g. due
+ * to an update)
+ */
+static int lookup_store(u64 target_nv_id, struct region_device *rstore)
+{
+	/* read_rdev, write_rdev and store_irdev need to be static to not go out of scope when
+	   this function returns */
+	static struct region_device read_rdev, write_rdev;
+	static struct incoherent_rdev store_irdev;
+	const char *name;
+	struct region region;
+	const struct region_device *rdev;
+
+	name = id_to_region_name(target_nv_id);
+	if (!name)
+		return -1;
+
+	if (fmap_locate_area(name, &region) < 0)
+		return -1;
+
+	if (boot_device_ro_subregion(&region, &read_rdev) < 0)
+		return -1;
+
+	if (boot_device_rw_subregion(&region, &write_rdev) < 0)
+		return -1;
+
+	rdev = incoherent_rdev_init(&store_irdev, &region, &read_rdev, &write_rdev);
+	if (rdev == NULL)
+		return -1;
+
+	return rdev_chain(rstore, rdev, 0, region_device_sz(rdev));
+}
+
+static inline enum mbox_p2c_status find_psp_spi_flash_device_region(u64 target_nv_id,
+							     struct region_device *store,
+							     const struct spi_flash **flash)
+{
+	*flash = boot_device_spi_flash();
+	if (*flash == NULL) {
+		printk(BIOS_ERR, "PSP: Unable to find SPI device\n");
+		return MBOX_PSP_COMMAND_PROCESS_ERROR;
+	}
+
+	if (lookup_store(target_nv_id, store) < 0) {
+		printk(BIOS_ERR, "PSP: Unable to find PSP SPI region\n");
+		return MBOX_PSP_COMMAND_PROCESS_ERROR;
+	}
+
+	return MBOX_PSP_SUCCESS;
+}
+
 enum mbox_p2c_status psp_smi_spi_get_info(struct mbox_default_buffer *buffer)
 {
    struct mbox_pspv2_cmd_spi_info *const cmd_buf =