// SPDX-License-Identifier: GPL-2.0
/* (C) 2015 Pengutronix, Alexander Aring <aar@pengutronix.de>
 *
 * Authors:
 * Alexander Aring <aar@pengutronix.de>
 * Eric Anholt <eric@anholt.net>
 */

#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pm_domain.h>
#include <dt-bindings/power/raspberrypi-power.h>
#include <soc/bcm2835/raspberrypi-firmware.h>

/*
 * Firmware indices for the old power domains interface.  Only a few
 * of them were actually implemented.
 */
#define RPI_OLD_POWER_DOMAIN_USB                3
#define RPI_OLD_POWER_DOMAIN_V3D                10

struct rpi_power_domain {
        u32 domain;
        bool enabled;
        bool old_interface;
        struct generic_pm_domain base;
        struct rpi_firmware *fw;
};

struct rpi_power_domains {
        bool has_new_interface;
        struct genpd_onecell_data xlate;
        struct rpi_firmware *fw;
        struct rpi_power_domain domains[RPI_POWER_DOMAIN_COUNT];
};

/*
 * Packet definition used by RPI_FIRMWARE_SET_POWER_STATE and
 * RPI_FIRMWARE_SET_DOMAIN_STATE
 */
struct rpi_power_domain_packet {
        u32 domain;
        u32 state;
};

/*
 * Asks the firmware to enable or disable power on a specific power
 * domain.
 */
static int rpi_firmware_set_power(struct generic_pm_domain *domain, bool on)
{
        struct rpi_power_domain *rpi_domain =
                container_of(domain, struct rpi_power_domain, base);
        bool old_interface = rpi_domain->old_interface;
        struct rpi_power_domain_packet packet;
        int ret;

        packet.domain = rpi_domain->domain;
        packet.state = on;

        ret = rpi_firmware_property(rpi_domain->fw, old_interface ?
                                    RPI_FIRMWARE_SET_POWER_STATE :
                                    RPI_FIRMWARE_SET_DOMAIN_STATE,
                                    &packet, sizeof(packet));
        if (ret)
                dev_err(&domain->dev, "Failed to set %s to %u (%d)\n",
                        old_interface ? "power" : "domain", on, ret);
        else
                dev_dbg(&domain->dev, "Set %s to %u\n",
                        old_interface ? "power" : "domain", on);

        return ret;
}

static int rpi_domain_off(struct generic_pm_domain *domain)
{
        return rpi_firmware_set_power(domain, false);
}

static int rpi_domain_on(struct generic_pm_domain *domain)
{
        return rpi_firmware_set_power(domain, true);
}

static void rpi_common_init_power_domain(struct rpi_power_domains *rpi_domains,
                                         int xlate_index, const char *name)
{
        struct rpi_power_domain *dom = &rpi_domains->domains[xlate_index];

        dom->fw = rpi_domains->fw;

        dom->base.name = name;
        dom->base.flags = GENPD_FLAG_ACTIVE_WAKEUP;
        dom->base.power_on = rpi_domain_on;
        dom->base.power_off = rpi_domain_off;

        /*
         * Treat all power domains as off at boot.
         *
         * The firmware itself may be keeping some domains on, but
         * from Linux's perspective all we control is the refcounts
         * that we give to the firmware, and we can't ask the firmware
         * to turn off something that we haven't ourselves turned on.
         */
        pm_genpd_init(&dom->base, NULL, true);

        rpi_domains->xlate.domains[xlate_index] = &dom->base;
}

static void rpi_init_power_domain(struct rpi_power_domains *rpi_domains,
                                  int xlate_index, const char *name)
{
        struct rpi_power_domain *dom = &rpi_domains->domains[xlate_index];

        if (!rpi_domains->has_new_interface)
                return;

        /* The DT binding index is the firmware's domain index minus one. */
        dom->domain = xlate_index + 1;

        rpi_common_init_power_domain(rpi_domains, xlate_index, name);
}

static void rpi_init_old_power_domain(struct rpi_power_domains *rpi_domains,
                                      int xlate_index, int domain,
                                      const char *name)
{
        struct rpi_power_domain *dom = &rpi_domains->domains[xlate_index];

        dom->old_interface = true;
        dom->domain = domain;

        rpi_common_init_power_domain(rpi_domains, xlate_index, name);
}

/*
 * Detects whether the firmware supports the new power domains interface.
 *
 * The firmware doesn't actually return an error on an unknown tag,
 * and just skips over it, so we do the detection by putting an
 * unexpected value in the return field and checking if it was
 * unchanged.
 */
static bool
rpi_has_new_domain_support(struct rpi_power_domains *rpi_domains)
{
        struct rpi_power_domain_packet packet;
        int ret;

        packet.domain = RPI_POWER_DOMAIN_ARM;
        packet.state = ~0;

        ret = rpi_firmware_property(rpi_domains->fw,
                                    RPI_FIRMWARE_GET_DOMAIN_STATE,
                                    &packet, sizeof(packet));

        return ret == 0 && packet.state != ~0;
}

static int rpi_power_probe(struct platform_device *pdev)
{
        struct device_node *fw_np;
        struct device *dev = &pdev->dev;
        struct rpi_power_domains *rpi_domains;

        rpi_domains = devm_kzalloc(dev, sizeof(*rpi_domains), GFP_KERNEL);
        if (!rpi_domains)
                return -ENOMEM;

        rpi_domains->xlate.domains =
                devm_kcalloc(dev,
                             RPI_POWER_DOMAIN_COUNT,
                             sizeof(*rpi_domains->xlate.domains),
                             GFP_KERNEL);
        if (!rpi_domains->xlate.domains)
                return -ENOMEM;

        rpi_domains->xlate.num_domains = RPI_POWER_DOMAIN_COUNT;

        fw_np = of_parse_phandle(pdev->dev.of_node, "firmware", 0);
        if (!fw_np) {
                dev_err(&pdev->dev, "no firmware node\n");
                return -ENODEV;
        }

        rpi_domains->fw = devm_rpi_firmware_get(&pdev->dev, fw_np);
        of_node_put(fw_np);
        if (!rpi_domains->fw)
                return -EPROBE_DEFER;

        rpi_domains->has_new_interface =
                rpi_has_new_domain_support(rpi_domains);

        rpi_init_power_domain(rpi_domains, RPI_POWER_DOMAIN_I2C0, "I2C0");
        rpi_init_power_domain(rpi_domains, RPI_POWER_DOMAIN_I2C1, "I2C1");
        rpi_init_power_domain(rpi_domains, RPI_POWER_DOMAIN_I2C2, "I2C2");
        rpi_init_power_domain(rpi_domains, RPI_POWER_DOMAIN_VIDEO_SCALER,
                              "VIDEO_SCALER");
        rpi_init_power_domain(rpi_domains, RPI_POWER_DOMAIN_VPU1, "VPU1");
        rpi_init_power_domain(rpi_domains, RPI_POWER_DOMAIN_HDMI, "HDMI");

        /*
         * Use the old firmware interface for USB power, so that we
         * can turn it on even if the firmware hasn't been updated.
         */
        rpi_init_old_power_domain(rpi_domains, RPI_POWER_DOMAIN_USB,
                                  RPI_OLD_POWER_DOMAIN_USB, "USB");

        rpi_init_power_domain(rpi_domains, RPI_POWER_DOMAIN_VEC, "VEC");
        rpi_init_power_domain(rpi_domains, RPI_POWER_DOMAIN_JPEG, "JPEG");
        rpi_init_power_domain(rpi_domains, RPI_POWER_DOMAIN_H264, "H264");
        rpi_init_power_domain(rpi_domains, RPI_POWER_DOMAIN_V3D, "V3D");
        rpi_init_power_domain(rpi_domains, RPI_POWER_DOMAIN_ISP, "ISP");
        rpi_init_power_domain(rpi_domains, RPI_POWER_DOMAIN_UNICAM0, "UNICAM0");
        rpi_init_power_domain(rpi_domains, RPI_POWER_DOMAIN_UNICAM1, "UNICAM1");
        rpi_init_power_domain(rpi_domains, RPI_POWER_DOMAIN_CCP2RX, "CCP2RX");
        rpi_init_power_domain(rpi_domains, RPI_POWER_DOMAIN_CSI2, "CSI2");
        rpi_init_power_domain(rpi_domains, RPI_POWER_DOMAIN_CPI, "CPI");
        rpi_init_power_domain(rpi_domains, RPI_POWER_DOMAIN_DSI0, "DSI0");
        rpi_init_power_domain(rpi_domains, RPI_POWER_DOMAIN_DSI1, "DSI1");
        rpi_init_power_domain(rpi_domains, RPI_POWER_DOMAIN_TRANSPOSER,
                              "TRANSPOSER");
        rpi_init_power_domain(rpi_domains, RPI_POWER_DOMAIN_CCP2TX, "CCP2TX");
        rpi_init_power_domain(rpi_domains, RPI_POWER_DOMAIN_CDP, "CDP");
        rpi_init_power_domain(rpi_domains, RPI_POWER_DOMAIN_ARM, "ARM");

        of_genpd_add_provider_onecell(dev->of_node, &rpi_domains->xlate);

        platform_set_drvdata(pdev, rpi_domains);

        return 0;
}

static const struct of_device_id rpi_power_of_match[] = {
        { .compatible = "raspberrypi,bcm2835-power", },
        {},
};
MODULE_DEVICE_TABLE(of, rpi_power_of_match);

static struct platform_driver rpi_power_driver = {
        .driver = {
                .name = "raspberrypi-power",
                .of_match_table = rpi_power_of_match,
        },
        .probe          = rpi_power_probe,
};
builtin_platform_driver(rpi_power_driver);

MODULE_AUTHOR("Alexander Aring <aar@pengutronix.de>");
MODULE_AUTHOR("Eric Anholt <eric@anholt.net>");
MODULE_DESCRIPTION("Raspberry Pi power domain driver");