acpi.c

Go to the documentation of this file.

/* SPDX-License-Identifier: GPL-2.0-only */
 
#include <acpi/acpi_device.h>
#include <acpi/acpigen.h>
#include <console/console.h>
#include <device/device.h>
#include <device/path.h>
#include <device/spi.h>
#include <spi-generic.h>
#include <string.h>
#include "chip.h"
 
static int spi_acpi_get_bus(const struct device *dev)
{
        struct device *spi_dev;
        struct device_operations *ops;
 
        if (!dev->bus || !dev->bus->dev)
                return -1;
 
        spi_dev = dev->bus->dev;
        ops = spi_dev->ops;
 
        if (ops && ops->ops_spi_bus &&
            ops->ops_spi_bus->dev_to_bus)
                return ops->ops_spi_bus->dev_to_bus(spi_dev);
 
        return -1;
}
 
static bool spi_acpi_add_gpios_to_crs(struct drivers_spi_acpi_config *config)
{
        /*
         * Return false if:
         * 1. Request to explicitly disable export of GPIOs in CRS, or
         * 2. Both reset and enable GPIOs are not provided.
         */
        if (config->disable_gpio_export_in_crs ||
            ((config->reset_gpio.pin_count == 0) &&
             (config->enable_gpio.pin_count == 0)))
                return false;
 
        return true;
}
 
static int spi_acpi_write_gpio(struct acpi_gpio *gpio, int *curr_index)
{
        int ret = -1;
 
        if (gpio->pin_count == 0)
                return ret;
 
        acpi_device_write_gpio(gpio);
        ret = *curr_index;
        (*curr_index)++;
 
        return ret;
}
 
static void spi_acpi_fill_ssdt_generator(const struct device *dev)
{
        struct drivers_spi_acpi_config *config = dev->chip_info;
        const char *scope = acpi_device_scope(dev);
        const char *path = acpi_device_path(dev);
        struct acpi_spi spi = {
                .device_select = dev->path.spi.cs,
                .speed = config->speed ? : 1 * MHz,
                .resource = scope,
                .device_select_polarity = SPI_POLARITY_LOW,
                .wire_mode = SPI_4_WIRE_MODE,
                .data_bit_length = 8,
                .clock_phase = SPI_CLOCK_PHASE_FIRST,
                .clock_polarity = SPI_POLARITY_LOW,
        };
        int curr_index = 0;
        int irq_gpio_index = -1;
        int reset_gpio_index = -1;
        int enable_gpio_index = -1;
 
        if (!scope)
                return;
 
        if (spi_acpi_get_bus(dev) == -1) {
                printk(BIOS_ERR, "%s: ERROR: Cannot get bus for device.\n",
                        dev_path(dev));
                return;
        }
 
        if (!config->hid) {
                printk(BIOS_ERR, "%s: ERROR: HID required.\n", dev_path(dev));
                return;
        }
 
        /* Device */
        acpigen_write_scope(scope);
        acpigen_write_device(acpi_device_name(dev));
        acpigen_write_name_string("_HID", config->hid);
        if (config->cid)
                acpigen_write_name_string("_CID", config->cid);
        acpigen_write_name_integer("_UID", config->uid);
        if (config->desc)
                acpigen_write_name_string("_DDN", config->desc);
        acpigen_write_STA(acpi_device_status(dev));
 
        /* Resources */
        acpigen_write_name("_CRS");
        acpigen_write_resourcetemplate_header();
        acpi_device_write_spi(&spi);
 
        /* Use either Interrupt() or GpioInt() */
        if (config->irq_gpio.pin_count)
                irq_gpio_index = spi_acpi_write_gpio(&config->irq_gpio,
                                                     &curr_index);
        else
                acpi_device_write_interrupt(&config->irq);
 
        /* Add enable/reset GPIOs if needed */
        if (spi_acpi_add_gpios_to_crs(config)) {
                reset_gpio_index = spi_acpi_write_gpio(&config->reset_gpio,
                                                       &curr_index);
                enable_gpio_index = spi_acpi_write_gpio(&config->enable_gpio,
                                                        &curr_index);
        }
        acpigen_write_resourcetemplate_footer();
 
        /* Wake capabilities */
        if (config->wake) {
                acpigen_write_name_integer("_S0W", ACPI_DEVICE_SLEEP_D3_HOT);
                acpigen_write_PRW(config->wake, 3);
        };
 
        /* Write device properties if needed */
        if (config->compat_string || irq_gpio_index >= 0 ||
            reset_gpio_index >= 0 || enable_gpio_index >= 0) {
                struct acpi_dp *dsd = acpi_dp_new_table("_DSD");
                if (config->compat_string)
                        acpi_dp_add_string(dsd, "compatible",
                                           config->compat_string);
                if (irq_gpio_index >= 0)
                        acpi_dp_add_gpio(dsd, "irq-gpios", path,
                                         irq_gpio_index, 0,
                                         config->irq_gpio.active_low);
                if (reset_gpio_index >= 0)
                        acpi_dp_add_gpio(dsd, "reset-gpios", path,
                                         reset_gpio_index, 0,
                                         config->reset_gpio.active_low);
                if (enable_gpio_index >= 0)
                        acpi_dp_add_gpio(dsd, "enable-gpios", path,
                                         enable_gpio_index, 0,
                                         config->enable_gpio.active_low);
                acpi_dp_write(dsd);
        }
 
        /* Power Resource */
        if (config->has_power_resource) {
                const struct acpi_power_res_params power_res_params = {
                        &config->reset_gpio,
                        config->reset_delay_ms,
                        config->reset_off_delay_ms,
                        &config->enable_gpio,
                        config->enable_delay_ms,
                        config->enable_off_delay_ms,
                        &config->stop_gpio,
                        config->stop_delay_ms,
                        config->stop_off_delay_ms
                };
                acpi_device_add_power_res(&power_res_params);
        }
 
        acpigen_pop_len(); /* Device */
        acpigen_pop_len(); /* Scope */
 
        printk(BIOS_INFO, "%s: %s at %s\n", path,
               config->desc ? : dev->chip_ops->name, dev_path(dev));
}
 
static const char *spi_acpi_name(const struct device *dev)
{
        struct drivers_spi_acpi_config *config = dev->chip_info;
        static char name[5];
 
        if (config->name)
                return config->name;
 
        snprintf(name, sizeof(name), "S%03.3X", spi_acpi_get_bus(dev));
        name[4] = '\0';
        return name;
}
 
static struct device_operations spi_acpi_ops = {
        .read_resources         = noop_read_resources,
        .set_resources          = noop_set_resources,
        .acpi_name              = spi_acpi_name,
        .acpi_fill_ssdt         = spi_acpi_fill_ssdt_generator,
};
 
static void spi_acpi_enable(struct device *dev)
{
        dev->ops = &spi_acpi_ops;
}
 
struct chip_operations drivers_spi_acpi_ops = {
        CHIP_NAME("SPI Device")
        .enable_dev = spi_acpi_enable
};