[PATCH v5 4/4] usb: xhci: provide a debugfs hook for erasing rom

Vinod Koul
2019-11-06T08:39:49Z

run "echo 1 > /sys/kernel/debug/renesas-usb/rom_erase" to erase firmware
when driver is loaded.

Subsequent init of driver shall reload the firmware

Signed-off-by: Vinod Koul <vkoul@kernel.org>
---
drivers/usb/host/xhci-pci.c | 34 ++++++++++++++++++++++++++++++++++
1 file changed, 34 insertions(+)

diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
index 4d0c0fd18c23..ac8f433861e9 100644
--- a/drivers/usb/host/xhci-pci.c
+++ b/drivers/usb/host/xhci-pci.c
@@ -14,6 +14,7 @@
#include <linux/acpi.h>
#include <linux/firmware.h>
#include <linux/unaligned/access_ok.h>
+#include <linux/debugfs.h>

#include "xhci.h"
#include "xhci-trace.h"
@@ -493,6 +494,8 @@ static int renesas_fw_verify(struct pci_dev *dev,
return 0;
}

+static void debugfs_init(struct pci_dev *pdev);
+
static int renesas_check_rom_state(struct pci_dev *pdev)
{
const struct renesas_fw_entry *entry;
@@ -516,6 +519,7 @@ static int renesas_check_rom_state(struct pci_dev *pdev)
if (version == entry->expected_version) {
dev_dbg(&pdev->dev, "Detected valid ROM version..\n");
valid_version = true;
+ debugfs_init(pdev);
}
}
if (valid_version == false)
@@ -803,6 +807,34 @@ static void renesas_rom_erase(struct pci_dev *pdev)
dev_dbg(&pdev->dev, "ROM Erase... Done success\n");
}

+static int debugfs_rom_erase(void *data, u64 value)
+{
+ struct pci_dev *pdev = data;
+
+ if (value == 1) {
+ dev_dbg(&pdev->dev, "Userspace requested ROM erase\n");
+ renesas_rom_erase(pdev);
+ return 0;
+ }
+ return -EINVAL;
+}
+DEFINE_DEBUGFS_ATTRIBUTE(rom_erase_ops, NULL, debugfs_rom_erase, "%llu\n");
+
+static struct dentry *debugfs_root;
+
+static void debugfs_init(struct pci_dev *pdev)
+{
+ debugfs_root = debugfs_create_dir("renesas-usb", NULL);
+
+ debugfs_create_file("rom_erase", 0200, debugfs_root,
+ pdev, &rom_erase_ops);
+}
+
+static void debugfs_exit(void)
+{
+ debugfs_remove_recursive(debugfs_root);
+}
+
static bool renesas_download_rom(struct pci_dev *pdev,
const u32 *fw, size_t step)
{
@@ -1248,6 +1280,8 @@ static void xhci_pci_remove(struct pci_dev *dev)
{
struct xhci_hcd *xhci;

+ debugfs_exit();
+
if (renesas_fw_alive_check(dev)) {
/*
* bail out early, if this was a renesas device w/o FW.
--
2.23.0