On Ampere Altra, PCIe hotplug is handled through ACPI. A side interface is
also present to request system firmware control of attention LEDs. Add an
ACPI PCI Hotplug companion driver to support attention LED control.
Signed-off-by: D Scott Phillips <scott@xxxxxxxxxxxxxxxxxxxxxx>
---
Changes since v1:
- remove build-as-module restriction
- add some more description
- don't open code PCI_SLOT()
- convert to a platform driver
drivers/pci/hotplug/Kconfig | 12 ++
drivers/pci/hotplug/Makefile | 1 +
drivers/pci/hotplug/acpiphp_ampere_altra.c | 127 +++++++++++++++++++++
3 files changed, 140 insertions(+)
create mode 100644 drivers/pci/hotplug/acpiphp_ampere_altra.c
diff --git a/drivers/pci/hotplug/Kconfig b/drivers/pci/hotplug/Kconfig
index 48113b210cf93..1472aef0fb812 100644
--- a/drivers/pci/hotplug/Kconfig
+++ b/drivers/pci/hotplug/Kconfig
@@ -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
diff --git a/drivers/pci/hotplug/Makefile b/drivers/pci/hotplug/Makefile
index 5196983220df6..240c99517d5e9 100644
--- a/drivers/pci/hotplug/Makefile
+++ b/drivers/pci/hotplug/Makefile
@@ -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
diff --git a/drivers/pci/hotplug/acpiphp_ampere_altra.c b/drivers/pci/hotplug/acpiphp_ampere_altra.c
new file mode 100644
index 0000000000000..1b1fe5d6a3fbf
--- /dev/null
+++ b/drivers/pci/hotplug/acpiphp_ampere_altra.c
@@ -0,0 +1,127 @@
+// 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_domain_nr(bus) | (PCI_SLOT(root_port->devfn) << 4), 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(&ere_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(&ere_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@xxxxxxxxxxxxxxxxxxxxxx>");
+MODULE_LICENSE("GPL");
--
2.41.0
