fw_config.c

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/* SPDX-License-Identifier: GPL-2.0-only */
 
#include <assert.h>
#include <bootstate.h>
#include <cbfs.h>
#include <console/console.h>
#include <device/device.h>
#include <ec/google/chromeec/ec.h>
#include <fw_config.h>
#include <inttypes.h>
#include <lib.h>
#include <stdbool.h>
#include <stdint.h>
#include <drivers/vpd/vpd.h>
 
uint64_t fw_config_get(void)
{
        static uint64_t fw_config_value;
        static bool fw_config_value_initialized;
 
        /* Nothing to prepare if setup is already done. */
        if (fw_config_value_initialized)
                return fw_config_value;
        fw_config_value_initialized = true;
        fw_config_value = UNDEFINED_FW_CONFIG;
 
        /* Read the value from EC CBI. */
        if (CONFIG(FW_CONFIG_SOURCE_CHROMEEC_CBI)) {
                if (google_chromeec_cbi_get_fw_config(&fw_config_value))
                        printk(BIOS_WARNING, "%s: Could not get fw_config from CBI\n",
                                __func__);
                else
                        printk(BIOS_INFO, "FW_CONFIG value from CBI is 0x%" PRIx64 "\n",
                                fw_config_value);
        }
 
        /* Look in CBFS to allow override of value. */
        if (CONFIG(FW_CONFIG_SOURCE_CBFS) && fw_config_value == UNDEFINED_FW_CONFIG) {
                if (cbfs_load(CONFIG_CBFS_PREFIX "/fw_config", &fw_config_value,
                              sizeof(fw_config_value)) != sizeof(fw_config_value))
                        printk(BIOS_WARNING, "%s: Could not get fw_config from CBFS\n",
                                __func__);
                else
                        printk(BIOS_INFO, "FW_CONFIG value from CBFS is 0x%" PRIx64 "\n",
                                fw_config_value);
        }
 
        if (CONFIG(FW_CONFIG_SOURCE_VPD) && fw_config_value == UNDEFINED_FW_CONFIG) {
                int vpd_value;
                if (vpd_get_int("fw_config", VPD_RW_THEN_RO, &vpd_value)) {
                        fw_config_value = vpd_value;
                        printk(BIOS_INFO, "FW_CONFIG value from VPD is 0x%" PRIx64 "\n",
                                fw_config_value);
                } else
                        printk(BIOS_WARNING, "%s: Could not get fw_config from vpd\n",
                                __func__);
        }
 
        return fw_config_value;
}
 
bool fw_config_probe(const struct fw_config *match)
{
        /* If fw_config is not provisioned, then there is nothing to match. */
        if (!fw_config_is_provisioned())
                return false;
 
        /* Compare to system value. */
        if ((fw_config_get() & match->mask) == match->value) {
                if (match->field_name && match->option_name)
                        printk(BIOS_INFO, "fw_config match found: %s=%s\n", match->field_name,
                               match->option_name);
                else
                        printk(BIOS_INFO, "fw_config match found: mask=0x%" PRIx64 " value=0x%"
                               PRIx64 "\n",
                               match->mask, match->value);
                return true;
        }
 
        return false;
}
 
bool fw_config_is_provisioned(void)
{
        return fw_config_get() != UNDEFINED_FW_CONFIG;
}
 
bool fw_config_probe_dev(const struct device *dev, const struct fw_config **matching_probe)
{
        const struct fw_config *probe;
 
        if (matching_probe)
                *matching_probe = NULL;
 
        /* If the device does not have a probe list, then probing is not required. */
        if (!dev->probe_list)
                return true;
 
        for (probe = dev->probe_list; probe && probe->mask != 0; probe++) {
                if (!fw_config_probe(probe))
                        continue;
 
                if (matching_probe)
                        *matching_probe = probe;
                return true;
        }
 
        return false;
}
 
#if ENV_RAMSTAGE
 
/*
 * The maximum number of fw_config fields is limited by the 64-bit mask that is used to
 * represent them.
 */
#define MAX_CACHE_ELEMENTS      (8 * sizeof(uint64_t))
 
static const struct fw_config *cached_configs[MAX_CACHE_ELEMENTS];
 
static size_t probe_index(uint64_t mask)
{
        assert(mask);
        return __ffs64(mask);
}
 
const struct fw_config *fw_config_get_found(uint64_t field_mask)
{
        const struct fw_config *config;
        config = cached_configs[probe_index(field_mask)];
        if (config && config->mask == field_mask)
                return config;
 
        return NULL;
}
 
void fw_config_for_each_found(void (*cb)(const struct fw_config *config, void *arg), void *arg)
{
        size_t i;
 
        for (i = 0; i < MAX_CACHE_ELEMENTS; ++i)
                if (cached_configs[i])
                        cb(cached_configs[i], arg);
}
 
static void fw_config_init(void *unused)
{
        struct device *dev;
 
        for (dev = all_devices; dev; dev = dev->next) {
                const struct fw_config *probe;
 
                if (!fw_config_probe_dev(dev, &probe)) {
                        printk(BIOS_INFO, "%s disabled by fw_config\n", dev_path(dev));
                        dev->enabled = 0;
                        continue;
                }
 
                if (probe)
                        cached_configs[probe_index(probe->mask)] = probe;
        }
}
BOOT_STATE_INIT_ENTRY(BS_DEV_INIT_CHIPS, BS_ON_ENTRY, fw_config_init, NULL);
#endif