--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-only OR MIT
+/*
+ * Apple SMC Reboot/Poweroff Handler
+ * Copyright The Asahi Linux Contributors
+ */
+
+#include <linux/delay.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/macsmc.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/nvmem-consumer.h>
+#include <linux/platform_device.h>
+#include <linux/reboot.h>
+#include <linux/slab.h>
+
+struct macsmc_reboot_nvmem {
+ struct nvmem_cell *shutdown_flag;
+ struct nvmem_cell *boot_stage;
+ struct nvmem_cell *boot_error_count;
+ struct nvmem_cell *panic_count;
+};
+
+static const char * const nvmem_names[] = {
+ "shutdown_flag",
+ "boot_stage",
+ "boot_error_count",
+ "panic_count",
+};
+
+enum boot_stage {
+ BOOT_STAGE_SHUTDOWN = 0x00, /* Clean shutdown */
+ BOOT_STAGE_IBOOT_DONE = 0x2f, /* Last stage of bootloader */
+ BOOT_STAGE_KERNEL_STARTED = 0x30, /* Normal OS booting */
+};
+
+struct macsmc_reboot {
+ struct device *dev;
+ struct apple_smc *smc;
+ struct notifier_block reboot_notify;
+
+ union {
+ struct macsmc_reboot_nvmem nvm;
+ struct nvmem_cell *nvm_cells[ARRAY_SIZE(nvmem_names)];
+ };
+};
+
+/* Helpers to read/write a u8 given a struct nvmem_cell */
+static int nvmem_cell_get_u8(struct nvmem_cell *cell)
+{
+ size_t len;
+ void *bfr;
+ u8 val;
+
+ bfr = nvmem_cell_read(cell, &len);
+ if (IS_ERR(bfr))
+ return PTR_ERR(bfr);
+
+ if (len < 1) {
+ kfree(bfr);
+ return -EINVAL;
+ }
+
+ val = *(u8 *)bfr;
+ kfree(bfr);
+ return val;
+}
+
+static int nvmem_cell_set_u8(struct nvmem_cell *cell, u8 val)
+{
+ return nvmem_cell_write(cell, &val, sizeof(val));
+}
+
+/*
+ * SMC 'MBSE' key actions:
+ *
+ * 'offw' - shutdown warning
+ * 'slpw' - sleep warning
+ * 'rest' - restart warning
+ * 'off1' - shutdown (needs PMU bit set to stay on)
+ * 'susp' - suspend
+ * 'phra' - restart ("PE Halt Restart Action"?)
+ * 'panb' - panic beginning
+ * 'pane' - panic end
+ */
+
+static int macsmc_prepare_atomic(struct sys_off_data *data)
+{
+ struct macsmc_reboot *reboot = data->cb_data;
+
+ dev_info(reboot->dev, "Preparing SMC for atomic mode\n");
+
+ apple_smc_enter_atomic(reboot->smc);
+ return NOTIFY_OK;
+}
+
+static int macsmc_power_off(struct sys_off_data *data)
+{
+ struct macsmc_reboot *reboot = data->cb_data;
+
+ dev_info(reboot->dev, "Issuing power off (off1)\n");
+
+ if (apple_smc_write_u32_atomic(reboot->smc, SMC_KEY(MBSE), SMC_KEY(off1)) < 0) {
+ dev_err(reboot->dev, "Failed to issue MBSE = off1 (power_off)\n");
+ } else {
+ mdelay(100);
+ WARN_ONCE(1, "Unable to power off system\n");
+ }
+
+ return NOTIFY_OK;
+}
+
+static int macsmc_restart(struct sys_off_data *data)
+{
+ struct macsmc_reboot *reboot = data->cb_data;
+
+ dev_info(reboot->dev, "Issuing restart (phra)\n");
+
+ if (apple_smc_write_u32_atomic(reboot->smc, SMC_KEY(MBSE), SMC_KEY(phra)) < 0) {
+ dev_err(reboot->dev, "Failed to issue MBSE = phra (restart)\n");
+ } else {
+ mdelay(100);
+ WARN_ONCE(1, "Unable to restart system\n");
+ }
+
+ return NOTIFY_OK;
+}
+
+static int macsmc_reboot_notify(struct notifier_block *this, unsigned long action, void *data)
+{
+ struct macsmc_reboot *reboot = container_of(this, struct macsmc_reboot, reboot_notify);
+ u8 shutdown_flag;
+ u32 val;
+
+ switch (action) {
+ case SYS_RESTART:
+ val = SMC_KEY(rest);
+ shutdown_flag = 0;
+ break;
+ case SYS_POWER_OFF:
+ val = SMC_KEY(offw);
+ shutdown_flag = 1;
+ break;
+ default:
+ return NOTIFY_DONE;
+ }
+
+ dev_info(reboot->dev, "Preparing for reboot (%p4ch)\n", &val);
+
+ /* On the Mac Mini, this will turn off the LED for power off */
+ if (apple_smc_write_u32(reboot->smc, SMC_KEY(MBSE), val) < 0)
+ dev_err(reboot->dev, "Failed to issue MBSE = %p4ch (reboot_prepare)\n", &val);
+
+ /* Set the boot_stage to 0, which means we're doing a clean shutdown/reboot. */
+ if (reboot->nvm.boot_stage &&
+ nvmem_cell_set_u8(reboot->nvm.boot_stage, BOOT_STAGE_SHUTDOWN) < 0)
+ dev_err(reboot->dev, "Failed to write boot_stage\n");
+
+ /*
+ * Set the PMU flag to actually reboot into the off state.
+ * Without this, the device will just reboot. We make it optional in case it is no longer
+ * necessary on newer hardware.
+ */
+ if (reboot->nvm.shutdown_flag &&
+ nvmem_cell_set_u8(reboot->nvm.shutdown_flag, shutdown_flag) < 0)
+ dev_err(reboot->dev, "Failed to write shutdown_flag\n");
+
+ return NOTIFY_OK;
+}
+
+static void macsmc_power_init_error_counts(struct macsmc_reboot *reboot)
+{
+ int boot_error_count, panic_count;
+
+ if (!reboot->nvm.boot_error_count || !reboot->nvm.panic_count)
+ return;
+
+ boot_error_count = nvmem_cell_get_u8(reboot->nvm.boot_error_count);
+ if (boot_error_count < 0) {
+ dev_err(reboot->dev, "Failed to read boot_error_count (%d)\n", boot_error_count);
+ return;
+ }
+
+ panic_count = nvmem_cell_get_u8(reboot->nvm.panic_count);
+ if (panic_count < 0) {
+ dev_err(reboot->dev, "Failed to read panic_count (%d)\n", panic_count);
+ return;
+ }
+
+ if (!boot_error_count && !panic_count)
+ return;
+
+ dev_warn(reboot->dev, "PMU logged %d boot error(s) and %d panic(s)\n",
+ boot_error_count, panic_count);
+
+ if (nvmem_cell_set_u8(reboot->nvm.panic_count, 0) < 0)
+ dev_err(reboot->dev, "Failed to reset panic_count\n");
+ if (nvmem_cell_set_u8(reboot->nvm.boot_error_count, 0) < 0)
+ dev_err(reboot->dev, "Failed to reset boot_error_count\n");
+}
+
+static int macsmc_reboot_probe(struct platform_device *pdev)
+{
+ struct apple_smc *smc = dev_get_drvdata(pdev->dev.parent);
+ struct macsmc_reboot *reboot;
+ int ret, i;
+
+ reboot = devm_kzalloc(&pdev->dev, sizeof(*reboot), GFP_KERNEL);
+ if (!reboot)
+ return -ENOMEM;
+
+ reboot->dev = &pdev->dev;
+ reboot->smc = smc;
+
+ platform_set_drvdata(pdev, reboot);
+
+ for (i = 0; i < ARRAY_SIZE(nvmem_names); i++) {
+ struct nvmem_cell *cell;
+
+ cell = devm_nvmem_cell_get(&pdev->dev,
+ nvmem_names[i]);
+ if (IS_ERR(cell)) {
+ if (PTR_ERR(cell) == -EPROBE_DEFER)
+ return -EPROBE_DEFER;
+ dev_warn(&pdev->dev, "Missing NVMEM cell %s (%ld)\n",
+ nvmem_names[i], PTR_ERR(cell));
+ /* Non fatal, we'll deal with it */
+ cell = NULL;
+ }
+ reboot->nvm_cells[i] = cell;
+ }
+
+ /* Set the boot_stage to indicate we're running the OS kernel */
+ if (reboot->nvm.boot_stage &&
+ nvmem_cell_set_u8(reboot->nvm.boot_stage, BOOT_STAGE_KERNEL_STARTED) < 0)
+ dev_err(reboot->dev, "Failed to write boot_stage\n");
+
+ /* Display and clear the error counts */
+ macsmc_power_init_error_counts(reboot);
+
+ reboot->reboot_notify.notifier_call = macsmc_reboot_notify;
+
+ ret = devm_register_sys_off_handler(&pdev->dev, SYS_OFF_MODE_POWER_OFF_PREPARE,
+ SYS_OFF_PRIO_HIGH, macsmc_prepare_atomic, reboot);
+ if (ret)
+ return dev_err_probe(&pdev->dev, ret,
+ "Failed to register power-off prepare handler\n");
+ ret = devm_register_sys_off_handler(&pdev->dev, SYS_OFF_MODE_POWER_OFF, SYS_OFF_PRIO_HIGH,
+ macsmc_power_off, reboot);
+ if (ret)
+ return dev_err_probe(&pdev->dev, ret,
+ "Failed to register power-off handler\n");
+
+ ret = devm_register_sys_off_handler(&pdev->dev, SYS_OFF_MODE_RESTART_PREPARE,
+ SYS_OFF_PRIO_HIGH, macsmc_prepare_atomic, reboot);
+ if (ret)
+ return dev_err_probe(&pdev->dev, ret,
+ "Failed to register restart prepare handler\n");
+ ret = devm_register_sys_off_handler(&pdev->dev, SYS_OFF_MODE_RESTART, SYS_OFF_PRIO_HIGH,
+ macsmc_restart, reboot);
+ if (ret)
+ return dev_err_probe(&pdev->dev, ret, "Failed to register restart handler\n");
+
+ ret = devm_register_reboot_notifier(&pdev->dev, &reboot->reboot_notify);
+ if (ret)
+ return dev_err_probe(&pdev->dev, ret, "Failed to register reboot notifier\n");
+
+ dev_info(&pdev->dev, "Handling reboot and poweroff requests via SMC\n");
+
+ return 0;
+}
+
+static const struct of_device_id macsmc_reboot_of_table[] = {
+ { .compatible = "apple,smc-reboot", },
+ {}
+};
+MODULE_DEVICE_TABLE(of, macsmc_reboot_of_table);
+
+static struct platform_driver macsmc_reboot_driver = {
+ .driver = {
+ .name = "macsmc-reboot",
+ .of_match_table = macsmc_reboot_of_table,
+ },
+ .probe = macsmc_reboot_probe,
+};
+module_platform_driver(macsmc_reboot_driver);
+
+MODULE_LICENSE("Dual MIT/GPL");
+MODULE_DESCRIPTION("Apple SMC reboot/poweroff driver");
+MODULE_AUTHOR("Hector Martin <marcan@marcan.st>");
projects / thirdparty / kernel / linux.git / commitdiff
