Commit 820f59ed authored by D Scott Phillips's avatar D Scott Phillips Committed by Bjorn Helgaas
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PCI: hotplug: Add Ampere Altra Attention Indicator extension driver 

On Ampere Altra, PCIe hotplug is handled through ACPI. A side interface is
also present to request system firmware control of the hotplug Attention
Indicators. Add an ACPI PCI Hotplug companion driver to support Attention
Indicator control.

Link: https://lore.kernel.org/r/20230930002036.6491-2-scott@os.amperecomputing.com


Signed-off-by: default avatarD Scott Phillips <scott@os.amperecomputing.com>
[bhelgaas: mask domain to low 4 bits]
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
Acked-by: default avatar"Rafael J. Wysocki" <rafael@kernel.org>
parent 33883eed

drivers/pci/hotplug/Kconfig

+12 −0
Original line number Diff line number Diff line
@@ -61,6 +61,18 @@ config HOTPLUG_PCI_ACPI 


	  When in doubt, say N.



config HOTPLUG_PCI_ACPI_AMPERE_ALTRA

	tristate "ACPI PCI Hotplug driver Ampere Altra extensions"

	depends on HOTPLUG_PCI_ACPI

	depends on HAVE_ARM_SMCCC_DISCOVERY

	help

	  Say Y here if you have an Ampere Altra system.



	  To compile this driver as a module, choose M here: the

	  module will be called acpiphp_ampere_altra.



	  When in doubt, say N.



config HOTPLUG_PCI_ACPI_IBM

	tristate "ACPI PCI Hotplug driver IBM extensions"

	depends on HOTPLUG_PCI_ACPI

drivers/pci/hotplug/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -23,6 +23,7 @@ obj-$(CONFIG_HOTPLUG_PCI_S390) += s390_pci_hpc.o 


# acpiphp_ibm extends acpiphp, so should be linked afterwards.



obj-$(CONFIG_HOTPLUG_PCI_ACPI_AMPERE_ALTRA)	+= acpiphp_ampere_altra.o

obj-$(CONFIG_HOTPLUG_PCI_ACPI_IBM)	+= acpiphp_ibm.o



pci_hotplug-objs	:=	pci_hotplug_core.o

drivers/pci/hotplug/acpiphp_ampere_altra.c

0 → 100644
+127 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

/*

 * ACPI PCI Hot Plug Extension for Ampere Altra. Allows control of

 * attention LEDs via requests to system firmware.

 *

 * Copyright (C) 2023 Ampere Computing LLC

 */



#define pr_fmt(fmt) "acpiphp_ampere_altra: " fmt



#include <linux/init.h>

#include <linux/module.h>

#include <linux/pci.h>

#include <linux/pci_hotplug.h>

#include <linux/platform_device.h>



#include "acpiphp.h"



#define HANDLE_OPEN	0xb0200000

#define HANDLE_CLOSE	0xb0300000

#define REQUEST		0xf0700000

#define LED_CMD		0x00000004

#define LED_ATTENTION	0x00000002

#define LED_SET_ON	0x00000001

#define LED_SET_OFF	0x00000002

#define LED_SET_BLINK	0x00000003



static u32 led_service_id[4];



static int led_status(u8 status)

{

	switch (status) {

	case 1: return LED_SET_ON;

	case 2: return LED_SET_BLINK;

	default: return LED_SET_OFF;

	}

}



static int set_attention_status(struct hotplug_slot *slot, u8 status)

{

	struct arm_smccc_res res;

	struct pci_bus *bus;

	struct pci_dev *root_port;

	unsigned long flags;

	u32 handle;

	int ret = 0;



	bus = slot->pci_slot->bus;

	root_port = pcie_find_root_port(bus->self);

	if (!root_port)

		return -ENODEV;



	local_irq_save(flags);

	arm_smccc_smc(HANDLE_OPEN, led_service_id[0], led_service_id[1],

		      led_service_id[2], led_service_id[3], 0, 0, 0, &res);

	if (res.a0) {

		ret = -ENODEV;

		goto out;

	}

	handle = res.a1 & 0xffff0000;



	arm_smccc_smc(REQUEST, LED_CMD, led_status(status), LED_ATTENTION,

		 (PCI_SLOT(root_port->devfn) << 4) | (pci_domain_nr(bus) & 0xf),

		 0, 0, handle, &res);

	if (res.a0)

		ret = -ENODEV;



	arm_smccc_smc(HANDLE_CLOSE, handle, 0, 0, 0, 0, 0, 0, &res);



 out:

	local_irq_restore(flags);

	return ret;

}



static int get_attention_status(struct hotplug_slot *slot, u8 *status)

{

	return -EINVAL;

}



static struct acpiphp_attention_info ampere_altra_attn = {

	.set_attn = set_attention_status,

	.get_attn = get_attention_status,

	.owner = THIS_MODULE,

};



static int altra_led_probe(struct platform_device *pdev)

{

	struct fwnode_handle *fwnode = dev_fwnode(&pdev->dev);

	int ret;



	ret = fwnode_property_read_u32_array(fwnode, "uuid", led_service_id, 4);

	if (ret) {

		dev_err(&pdev->dev, "can't find uuid\n");

		return ret;

	}



	ret = acpiphp_register_attention(&ampere_altra_attn);

	if (ret) {

		dev_err(&pdev->dev, "can't register driver\n");

		return ret;

	}

	return 0;

}



static void altra_led_remove(struct platform_device *pdev)

{

	acpiphp_unregister_attention(&ampere_altra_attn);

}



static const struct acpi_device_id altra_led_ids[] = {

	{ "AMPC0008", 0 },

	{ }

};

MODULE_DEVICE_TABLE(acpi, altra_led_ids);



static struct platform_driver altra_led_driver = {

	.driver = {

		.name = "ampere-altra-leds",

		.acpi_match_table = altra_led_ids,

	},

	.probe = altra_led_probe,

	.remove_new = altra_led_remove,

};

module_platform_driver(altra_led_driver);



MODULE_AUTHOR("D Scott Phillips <scott@os.amperecomputing.com>");

MODULE_LICENSE("GPL");