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Message-ID: <20260210224023.2341728-3-vvidwans@nvidia.com>
Date: Tue, 10 Feb 2026 22:40:23 +0000
From: Vedashree Vidwans <vvidwans@...dia.com>
To: <salman.nabi@....com>, <sudeep.holla@....com>, <andre.przywara@....com>,
<lpieralisi@...nel.org>, <mark.rutland@....com>,
<trilokkumar.soni@....qualcomm.com>
CC: <ardb@...nel.org>, <chao.gao@...el.com>,
<linux-arm-kernel@...ts.infradead.org>, <linux-coco@...ts.linux.dev>,
<linux-kernel@...r.kernel.org>, <sdonthineni@...dia.com>,
<vsethi@...dia.com>, <vwadekar@...dia.com>, Vedashree Vidwans
<vvidwans@...dia.com>
Subject: [PATCH 2/2] firmware: smccc: register as platform driver
- Register the LFA driver as a platform driver corresponding to
'arml0003' ACPI device. The driver will be invoked when the device is
detected on a platform. NOTE: current functionality only available for
ACPI configuration.
- Add functionality to register ACPI notify handler for LFA in the
driver probe().
- When notify handler is invoked, driver will query latest FW component
details and trigger activation of capable and pending FW component in a
loop until all FWs are activated.
ACPI node snippet from LFA spec[1]:
Device (LFA0) {
Name (_HID, "ARML0003")
Name (_UID, 0)
}
[1] https://developer.arm.com/documentation/den0147/latest/
Signed-off-by: Vedashree Vidwans <vvidwans@...dia.com>
---
drivers/firmware/smccc/lfa_fw.c | 153 ++++++++++++++++++++++++++++----
1 file changed, 134 insertions(+), 19 deletions(-)
diff --git a/drivers/firmware/smccc/lfa_fw.c b/drivers/firmware/smccc/lfa_fw.c
index b0ace6fc8dac..042de937bf83 100644
--- a/drivers/firmware/smccc/lfa_fw.c
+++ b/drivers/firmware/smccc/lfa_fw.c
@@ -20,7 +20,10 @@
#include <linux/nmi.h>
#include <linux/ktime.h>
#include <linux/delay.h>
+#include <linux/acpi.h>
+#include <linux/platform_device.h>
+#define DRIVER_NAME "ARM_LFA"
#undef pr_fmt
#define pr_fmt(fmt) "Arm LFA: " fmt
@@ -284,26 +287,7 @@ static int activate_fw_image(struct image_props *attrs)
return lfa_cancel(attrs);
}
- /*
- * Invalidate fw_seq_ids (-1) for all images as the seq_ids and the
- * number of firmware images in the LFA agent may change after a
- * successful activation attempt. Negate all image flags as well.
- */
- attrs = NULL;
- list_for_each_entry(attrs, &lfa_fw_images, image_node) {
- set_image_flags(attrs, -1, 0b1000, 0, 0);
- }
-
update_fw_images_tree();
-
- /*
- * Removing non-valid image directories at the end of an activation.
- * We can't remove the sysfs attributes while in the respective
- * _store() handler, so have to postpone the list removal to a
- * workqueue.
- */
- INIT_WORK(&fw_images_update_work, remove_invalid_fw_images);
- queue_work(fw_images_update_wq, &fw_images_update_work);
mutex_unlock(&lfa_lock);
return ret;
@@ -627,6 +611,7 @@ static int update_fw_images_tree(void)
{
struct arm_smccc_1_2_regs reg = { 0 };
struct uuid_regs image_uuid;
+ struct image_props *attrs;
char image_id_str[40];
int ret, num_of_components;
@@ -636,6 +621,15 @@ static int update_fw_images_tree(void)
return -ENODEV;
}
+ /*
+ * Invalidate fw_seq_ids (-1) for all images as the seq_ids and the
+ * number of firmware images in the LFA agent may change after a
+ * successful activation attempt. Negate all image flags as well.
+ */
+ list_for_each_entry(attrs, &lfa_fw_images, image_node) {
+ set_image_flags(attrs, -1, 0b1000, 0, 0);
+ }
+
for (int i = 0; i < num_of_components; i++) {
reg.a0 = LFA_1_0_FN_GET_INVENTORY;
reg.a1 = i; /* fw_seq_id under consideration */
@@ -653,9 +647,121 @@ static int update_fw_images_tree(void)
}
}
+ /*
+ * Removing non-valid image directories at the end of an activation.
+ * We can't remove the sysfs attributes while in the respective
+ * _store() handler, so have to postpone the list removal to a
+ * workqueue.
+ */
+ INIT_WORK(&fw_images_update_work, remove_invalid_fw_images);
+ queue_work(fw_images_update_wq, &fw_images_update_work);
+
+ return 0;
+}
+
+#if defined(CONFIG_ACPI)
+static void lfa_notify_handler(acpi_handle handle, u32 event, void *data)
+{
+ struct image_props *attrs = NULL;
+ int ret;
+ bool found_activable_image = false;
+
+ /* Get latest FW inventory */
+ mutex_lock(&lfa_lock);
+ ret = update_fw_images_tree();
+ mutex_unlock(&lfa_lock);
+ if (ret != 0) {
+ pr_err("FW images tree update failed");
+ return;
+ }
+
+ /*
+ * Go through all FW images in a loop and trigger activation
+ * of all activable and pending images.
+ */
+ do {
+ /* Reset activable image flag */
+ found_activable_image = false;
+ list_for_each_entry(attrs, &lfa_fw_images, image_node) {
+ if (attrs->fw_seq_id == -1)
+ continue; /* Invalid FW component */
+
+ if ((!attrs->activation_capable) || (!attrs->activation_pending))
+ continue; /* FW component is not activable */
+
+ /*
+ * Found an image that is activable.
+ * As the FW images tree is revised after activation, it is
+ * not ideal to invoke activation from inside
+ * list_for_each_entry() loop.
+ * So, set the flasg and exit loop.
+ */
+ found_activable_image = true;
+ break;
+ }
+
+ if (found_activable_image) {
+ ret = prime_fw_image(attrs);
+ if (ret) {
+ pr_err("Firmware prime failed: %s\n",
+ lfa_error_strings[-ret]);
+ return;
+ }
+
+ ret = activate_fw_image(attrs);
+ if (ret) {
+ pr_err("Firmware activation failed: %s\n",
+ lfa_error_strings[-ret]);
+ return;
+ }
+
+ pr_info("Firmware %s activation succeeded", attrs->image_name);
+ }
+ } while (found_activable_image);
+}
+
+static int lfa_probe(struct platform_device *pdev)
+{
+ acpi_status status;
+ acpi_handle handle = ACPI_HANDLE(&pdev->dev);
+
+ if (!handle)
+ return -ENODEV;
+
+ /* Register notify handler that indicates if LFA updates are available */
+ status = acpi_install_notify_handler(handle,
+ ACPI_DEVICE_NOTIFY, lfa_notify_handler, pdev);
+ if (ACPI_FAILURE(status))
+ return -EIO;
+
return 0;
}
+static void lfa_remove(struct platform_device *pdev)
+{
+ acpi_handle handle = ACPI_HANDLE(&pdev->dev);
+
+ if (handle)
+ acpi_remove_notify_handler(handle,
+ ACPI_DEVICE_NOTIFY, lfa_notify_handler);
+}
+
+static const struct acpi_device_id lfa_acpi_ids[] = {
+ {"ARML0003"},
+ {},
+};
+MODULE_DEVICE_TABLE(acpi, lfa_acpi_ids);
+
+static struct platform_driver lfa_driver = {
+ .probe = lfa_probe,
+ .remove = lfa_remove,
+ .driver = {
+ .name = DRIVER_NAME,
+ .acpi_match_table = ACPI_PTR(lfa_acpi_ids),
+ },
+};
+#endif
+
static int __init lfa_init(void)
{
struct arm_smccc_1_2_regs reg = { 0 };
@@ -679,6 +785,12 @@ static int __init lfa_init(void)
pr_info("Live Firmware Activation: detected v%ld.%ld\n",
reg.a0 >> 16, reg.a0 & 0xffff);
+#if defined(CONFIG_ACPI)
+ err = platform_driver_register(&lfa_driver);
+ if (err < 0)
+ pr_err("Platform driver register failed");
+#endif
+
lfa_dir = kobject_create_and_add("lfa", firmware_kobj);
if (!lfa_dir)
return -ENOMEM;
@@ -703,6 +815,9 @@ static void __exit lfa_exit(void)
mutex_unlock(&lfa_lock);
kobject_put(lfa_dir);
+#if defined(CONFIG_ACPI)
+ platform_driver_unregister(&lfa_driver);
+#endif
}
module_exit(lfa_exit);
--
2.43.0
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