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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274// SPDX-License-Identifier: GPL-2.0+/* * Surface Book (2 and later) hot-plug driver. * * Surface Book devices (can) have a hot-pluggable discrete GPU (dGPU). This * driver is responsible for out-of-band hot-plug event signaling on these * devices. It is specifically required when the hot-plug device is in D3cold * and can thus not generate PCIe hot-plug events itself. * * Event signaling is handled via ACPI, which will generate the appropriate * device-check notifications to be picked up by the PCIe hot-plug driver. * * Copyright (C) 2019-2022 Maximilian Luz <luzmaximilian@gmail.com> */
#include <linux/acpi.h>#include <linux/gpio/consumer.h>#include <linux/interrupt.h>#include <linux/kernel.h>#include <linux/module.h>#include <linux/mutex.h>#include <linux/platform_device.h>
static const struct acpi_gpio_params shps_base_presence_int = { 0, 0, false };static const struct acpi_gpio_params shps_base_presence = { 1, 0, false };static const struct acpi_gpio_params shps_device_power_int = { 2, 0, false };static const struct acpi_gpio_params shps_device_power = { 3, 0, false };static const struct acpi_gpio_params shps_device_presence_int = { 4, 0, false };static const struct acpi_gpio_params shps_device_presence = { 5, 0, false };
static const struct acpi_gpio_mapping shps_acpi_gpios[] = { { "base_presence-int-gpio", &shps_base_presence_int, 1 }, { "base_presence-gpio", &shps_base_presence, 1 }, { "device_power-int-gpio", &shps_device_power_int, 1 }, { "device_power-gpio", &shps_device_power, 1 }, { "device_presence-int-gpio", &shps_device_presence_int, 1 }, { "device_presence-gpio", &shps_device_presence, 1 }, { },};
/* 5515a847-ed55-4b27-8352-cd320e10360a */static const guid_t shps_dsm_guid = GUID_INIT(0x5515a847, 0xed55, 0x4b27, 0x83, 0x52, 0xcd, 0x32, 0x0e, 0x10, 0x36, 0x0a);
#define SHPS_DSM_REVISION 1
enum shps_dsm_fn { SHPS_DSM_FN_PCI_NUM_ENTRIES = 0x01, SHPS_DSM_FN_PCI_GET_ENTRIES = 0x02, SHPS_DSM_FN_IRQ_BASE_PRESENCE = 0x03, SHPS_DSM_FN_IRQ_DEVICE_POWER = 0x04, SHPS_DSM_FN_IRQ_DEVICE_PRESENCE = 0x05,};
enum shps_irq_type { /* NOTE: Must be in order of enum shps_dsm_fn above. */ SHPS_IRQ_TYPE_BASE_PRESENCE = 0, SHPS_IRQ_TYPE_DEVICE_POWER = 1, SHPS_IRQ_TYPE_DEVICE_PRESENCE = 2, SHPS_NUM_IRQS,};
static const char *const shps_gpio_names[] = { [SHPS_IRQ_TYPE_BASE_PRESENCE] = "base_presence", [SHPS_IRQ_TYPE_DEVICE_POWER] = "device_power", [SHPS_IRQ_TYPE_DEVICE_PRESENCE] = "device_presence",};
struct shps_device { struct mutex lock[SHPS_NUM_IRQS]; /* Protects update in shps_dsm_notify_irq() */ struct gpio_desc *gpio[SHPS_NUM_IRQS]; unsigned int irq[SHPS_NUM_IRQS];};
#define SHPS_IRQ_NOT_PRESENT ((unsigned int)-1)
static enum shps_dsm_fn shps_dsm_fn_for_irq(enum shps_irq_type type){ return SHPS_DSM_FN_IRQ_BASE_PRESENCE + type;}
static void shps_dsm_notify_irq(struct platform_device *pdev, enum shps_irq_type type){ struct shps_device *sdev = platform_get_drvdata(pdev); acpi_handle handle = ACPI_HANDLE(&pdev->dev); union acpi_object *result; union acpi_object param; int value;
mutex_lock(&sdev->lock[type]);
value = gpiod_get_value_cansleep(sdev->gpio[type]); if (value < 0) { mutex_unlock(&sdev->lock[type]); dev_err(&pdev->dev, "failed to get gpio: %d (irq=%d)\n", type, value); return; }
dev_dbg(&pdev->dev, "IRQ notification via DSM (irq=%d, value=%d)\n", type, value);
param.type = ACPI_TYPE_INTEGER; param.integer.value = value;
result = acpi_evaluate_dsm_typed(handle, &shps_dsm_guid, SHPS_DSM_REVISION, shps_dsm_fn_for_irq(type), ¶m, ACPI_TYPE_BUFFER); if (!result) { dev_err(&pdev->dev, "IRQ notification via DSM failed (irq=%d, gpio=%d)\n", type, value);
} else if (result->buffer.length != 1 || result->buffer.pointer[0] != 0) { dev_err(&pdev->dev, "IRQ notification via DSM failed: unexpected result value (irq=%d, gpio=%d)\n", type, value); }
mutex_unlock(&sdev->lock[type]);
ACPI_FREE(result);}
static irqreturn_t shps_handle_irq(int irq, void *data){ struct platform_device *pdev = data; struct shps_device *sdev = platform_get_drvdata(pdev); int type;
/* Figure out which IRQ we're handling. */ for (type = 0; type < SHPS_NUM_IRQS; type++) if (irq == sdev->irq[type]) break;
/* We should have found our interrupt, if not: this is a bug. */ if (WARN(type >= SHPS_NUM_IRQS, "invalid IRQ number: %d\n", irq)) return IRQ_HANDLED;
/* Forward interrupt to ACPI via DSM. */ shps_dsm_notify_irq(pdev, type); return IRQ_HANDLED;}
static int shps_setup_irq(struct platform_device *pdev, enum shps_irq_type type){ unsigned long flags = IRQF_ONESHOT | IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING; struct shps_device *sdev = platform_get_drvdata(pdev); struct gpio_desc *gpiod; acpi_handle handle = ACPI_HANDLE(&pdev->dev); const char *irq_name; const int dsm = shps_dsm_fn_for_irq(type); int status, irq;
/* * Only set up interrupts that we actually need: The Surface Book 3 * does not have a DSM for base presence, so don't set up an interrupt * for that. */ if (!acpi_check_dsm(handle, &shps_dsm_guid, SHPS_DSM_REVISION, BIT(dsm))) { dev_dbg(&pdev->dev, "IRQ notification via DSM not present (irq=%d)\n", type); return 0; }
gpiod = devm_gpiod_get(&pdev->dev, shps_gpio_names[type], GPIOD_ASIS); if (IS_ERR(gpiod)) return PTR_ERR(gpiod);
irq = gpiod_to_irq(gpiod); if (irq < 0) return irq;
irq_name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "shps-irq-%d", type); if (!irq_name) return -ENOMEM;
status = devm_request_threaded_irq(&pdev->dev, irq, NULL, shps_handle_irq, flags, irq_name, pdev); if (status) return status;
dev_dbg(&pdev->dev, "set up irq %d as type %d\n", irq, type);
sdev->gpio[type] = gpiod; sdev->irq[type] = irq;
return 0;}
static void surface_hotplug_remove(struct platform_device *pdev){ struct shps_device *sdev = platform_get_drvdata(pdev); int i;
/* Ensure that IRQs have been fully handled and won't trigger any more. */ for (i = 0; i < SHPS_NUM_IRQS; i++) { if (sdev->irq[i] != SHPS_IRQ_NOT_PRESENT) disable_irq(sdev->irq[i]);
mutex_destroy(&sdev->lock[i]); }}
static int surface_hotplug_probe(struct platform_device *pdev){ struct shps_device *sdev; int status, i;
/* * The MSHW0153 device is also present on the Surface Laptop 3, * however that doesn't have a hot-pluggable PCIe device. It also * doesn't have any GPIO interrupts/pins under the MSHW0153, so filter * it out here. */ if (gpiod_count(&pdev->dev, NULL) < 0) return -ENODEV;
status = devm_acpi_dev_add_driver_gpios(&pdev->dev, shps_acpi_gpios); if (status) return status;
sdev = devm_kzalloc(&pdev->dev, sizeof(*sdev), GFP_KERNEL); if (!sdev) return -ENOMEM;
platform_set_drvdata(pdev, sdev);
/* * Initialize IRQs so that we can safely call surface_hotplug_remove() * on errors. */ for (i = 0; i < SHPS_NUM_IRQS; i++) sdev->irq[i] = SHPS_IRQ_NOT_PRESENT;
/* Set up IRQs. */ for (i = 0; i < SHPS_NUM_IRQS; i++) { mutex_init(&sdev->lock[i]);
status = shps_setup_irq(pdev, i); if (status) { dev_err(&pdev->dev, "failed to set up IRQ %d: %d\n", i, status); goto err; } }
/* Ensure everything is up-to-date. */ for (i = 0; i < SHPS_NUM_IRQS; i++) if (sdev->irq[i] != SHPS_IRQ_NOT_PRESENT) shps_dsm_notify_irq(pdev, i);
return 0;
err: surface_hotplug_remove(pdev); return status;}
static const struct acpi_device_id surface_hotplug_acpi_match[] = { { "MSHW0153", 0 }, { },};MODULE_DEVICE_TABLE(acpi, surface_hotplug_acpi_match);
static struct platform_driver surface_hotplug_driver = { .probe = surface_hotplug_probe, .remove = surface_hotplug_remove, .driver = { .name = "surface_hotplug", .acpi_match_table = surface_hotplug_acpi_match, .probe_type = PROBE_PREFER_ASYNCHRONOUS, },};module_platform_driver(surface_hotplug_driver);
MODULE_AUTHOR("Maximilian Luz <luzmaximilian@gmail.com>");MODULE_DESCRIPTION("Surface Hot-Plug Signaling Driver for Surface Book Devices");MODULE_LICENSE("GPL");