[PATCH v2 01/12] usb: xhci: add sysfs file for xHCI debug port
From: Lu Baolu
Date: Tue Nov 03 2015 - 03:17:47 EST
This patch adds a sysfs file for users to check 1) whether the debug
capability is implemented by hardware; 2) if supported, which state
does it stay at.
With a host that supports debug port, a file named "debug_port_state"
will be created under the device sysfs directory. Reading this file
will show users the state (disabled, enabled or configured) of the
debug port.
With a host that does NOT support debug port, "debug_port_state" file
won't be created.
Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
---
.../ABI/testing/sysfs-bus-pci-drivers-xhci_hcd | 23 +++++
drivers/usb/host/Makefile | 2 +-
drivers/usb/host/xhci-ext-caps.h | 14 ++-
drivers/usb/host/xhci-sysfs.c | 100 +++++++++++++++++++++
drivers/usb/host/xhci.c | 4 +
drivers/usb/host/xhci.h | 4 +
6 files changed, 145 insertions(+), 2 deletions(-)
create mode 100644 Documentation/ABI/testing/sysfs-bus-pci-drivers-xhci_hcd
create mode 100644 drivers/usb/host/xhci-sysfs.c
diff --git a/Documentation/ABI/testing/sysfs-bus-pci-drivers-xhci_hcd b/Documentation/ABI/testing/sysfs-bus-pci-drivers-xhci_hcd
new file mode 100644
index 0000000..dd3e722
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-bus-pci-drivers-xhci_hcd
@@ -0,0 +1,23 @@
+What: /sys/bus/pci/drivers/xhci_hcd/.../debug_port_state
+Date: November 2015
+KernelVersion: 4.3.0
+Contact: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
+Description:
+ This file is designed for users to check the state of a
+ USB3 debug port. On a machine which supports USB3 debug
+ port, this file will be created. Reading this file will
+ show the state (disabled, enabled or configured) of the
+ debug port. On a machine that doesn't support USB3 debug
+ port, this file doesn't exist.
+
+ The state of a debug port could be:
+ 1) disabled: The debug port is not enabled and the root
+ port has been switched to xHCI host as a normal
+ root port.
+ 2) enabled: The debug port is enabled. The debug port
+ has been assigned to debug capability. The debug
+ capability is able to handle the control requests
+ defined in USB3 spec.
+ 3) configured: The debug port has been enumerated by the
+ debug host as a debug device. The debug port is
+ in use now.
diff --git a/drivers/usb/host/Makefile b/drivers/usb/host/Makefile
index e7558ab..810c304 100644
--- a/drivers/usb/host/Makefile
+++ b/drivers/usb/host/Makefile
@@ -12,7 +12,7 @@ fhci-$(CONFIG_FHCI_DEBUG) += fhci-dbg.o
xhci-hcd-y := xhci.o xhci-mem.o
xhci-hcd-y += xhci-ring.o xhci-hub.o xhci-dbg.o
-xhci-hcd-y += xhci-trace.o
+xhci-hcd-y += xhci-trace.o xhci-sysfs.o
xhci-plat-hcd-y := xhci-plat.o
ifneq ($(CONFIG_USB_XHCI_MVEBU), )
diff --git a/drivers/usb/host/xhci-ext-caps.h b/drivers/usb/host/xhci-ext-caps.h
index 9fe3225..12c87e5 100644
--- a/drivers/usb/host/xhci-ext-caps.h
+++ b/drivers/usb/host/xhci-ext-caps.h
@@ -49,8 +49,15 @@
#define XHCI_EXT_CAPS_PM 3
#define XHCI_EXT_CAPS_VIRT 4
#define XHCI_EXT_CAPS_ROUTE 5
-/* IDs 6-9 reserved */
+#define XHCI_EXT_CAPS_LOCALMEM 6
+/* IDs 7-9 reserved */
#define XHCI_EXT_CAPS_DEBUG 10
+/* IDs 192-255 vendor specific */
+#define XHCI_EXT_CAPS_VEN_START 192
+#define XHCI_EXT_CAPS_VEN_END 255
+#define XHCI_EXT_CAPS_VENDOR(p) (((p) >= XHCI_EXT_CAPS_VEN_START) && \
+ ((p) <= XHCI_EXT_CAPS_VEN_END))
+#define XHCI_EXT_MAX_CAPID XHCI_EXT_CAPS_VEN_END
/* USB Legacy Support Capability - section 7.1.1 */
#define XHCI_HC_BIOS_OWNED (1 << 16)
#define XHCI_HC_OS_OWNED (1 << 24)
@@ -73,6 +80,11 @@
#define XHCI_HLC (1 << 19)
#define XHCI_BLC (1 << 20)
+/* Debug capability - section 7.6.8 */
+#define XHCI_DBC_DCCTRL 0x20
+#define XHCI_DBC_DCCTRL_DCR (1 << 0)
+#define XHCI_DBC_DCCTRL_DCE (1 << 31)
+
/* command register values to disable interrupts and halt the HC */
/* start/stop HC execution - do not write unless HC is halted*/
#define XHCI_CMD_RUN (1 << 0)
diff --git a/drivers/usb/host/xhci-sysfs.c b/drivers/usb/host/xhci-sysfs.c
new file mode 100644
index 0000000..0192ac4
--- /dev/null
+++ b/drivers/usb/host/xhci-sysfs.c
@@ -0,0 +1,100 @@
+/*
+ * sysfs interface for xHCI host controller driver
+ *
+ * Copyright (C) 2015 Intel Corp.
+ *
+ * Author: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/kernel.h>
+
+#include "xhci.h"
+
+/*
+ * Return the register offset of a extended capability specified
+ * by @cap_id. Return 0 if @cap_id capability is not supported or
+ * in error cases.
+ */
+static int get_extended_capability_offset(struct xhci_hcd *xhci,
+ int cap_id)
+{
+ u32 cap_reg;
+ unsigned long flags;
+ int offset;
+ void __iomem *base = (void __iomem *) xhci->cap_regs;
+ struct usb_hcd *hcd = xhci_to_hcd(xhci);
+ int time_to_leave = XHCI_EXT_MAX_CAPID;
+
+ spin_lock_irqsave(&xhci->lock, flags);
+
+ offset = xhci_find_next_cap_offset(base, XHCI_HCC_PARAMS_OFFSET);
+ if (!HCD_HW_ACCESSIBLE(hcd) || !offset) {
+ spin_unlock_irqrestore(&xhci->lock, flags);
+ return 0;
+ }
+
+ while (time_to_leave--) {
+ cap_reg = readl(base + offset);
+
+ if (XHCI_EXT_CAPS_ID(cap_reg) == cap_id)
+ break;
+
+ offset = xhci_find_next_cap_offset(base, offset);
+ if (!offset)
+ break;
+ }
+
+ spin_unlock_irqrestore(&xhci->lock, flags);
+
+ return offset;
+}
+
+static ssize_t debug_port_state_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ int count = 0, offset;
+ char *state;
+ void __iomem *dbc_base;
+ u32 dcctrl_reg;
+ struct xhci_hcd *xhci = hcd_to_xhci(dev_get_drvdata(dev));
+
+ offset = get_extended_capability_offset(xhci, XHCI_EXT_CAPS_DEBUG);
+ if (!offset)
+ return 0;
+
+ dbc_base = (void __iomem *) xhci->cap_regs + offset;
+ dcctrl_reg = readl(dbc_base + XHCI_DBC_DCCTRL);
+
+ if (!(dcctrl_reg & XHCI_DBC_DCCTRL_DCE))
+ state = "disabled";
+ else if (dcctrl_reg & XHCI_DBC_DCCTRL_DCR)
+ state = "configured";
+ else
+ state = "enabled";
+
+ count = scnprintf(buf, PAGE_SIZE, "%s\n", state);
+
+ return count;
+}
+static DEVICE_ATTR_RO(debug_port_state);
+
+int xhci_sysfs_create_files(struct xhci_hcd *xhci)
+{
+ struct device *dev = xhci_to_hcd(xhci)->self.controller;
+
+ if (get_extended_capability_offset(xhci, XHCI_EXT_CAPS_DEBUG))
+ return device_create_file(dev, &dev_attr_debug_port_state);
+
+ return 0;
+}
+
+void xhci_sysfs_remove_files(struct xhci_hcd *xhci)
+{
+ struct device *dev = xhci_to_hcd(xhci)->self.controller;
+
+ if (get_extended_capability_offset(xhci, XHCI_EXT_CAPS_DEBUG))
+ device_remove_file(dev, &dev_attr_debug_port_state);
+}
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 6e7dc6f..583b59f 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -651,6 +651,9 @@ int xhci_run(struct usb_hcd *hcd)
}
xhci_dbg_trace(xhci, trace_xhci_dbg_init,
"Finished xhci_run for USB2 roothub");
+
+ xhci_sysfs_create_files(xhci);
+
return 0;
}
EXPORT_SYMBOL_GPL(xhci_run);
@@ -684,6 +687,7 @@ void xhci_stop(struct usb_hcd *hcd)
xhci_reset(xhci);
spin_unlock_irq(&xhci->lock);
+ xhci_sysfs_remove_files(xhci);
xhci_cleanup_msix(xhci);
/* Deleting Compliance Mode Recovery Timer */
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index be9048e..6bd2e6a 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1950,4 +1950,8 @@ struct xhci_input_control_ctx *xhci_get_input_control_ctx(struct xhci_container_
struct xhci_slot_ctx *xhci_get_slot_ctx(struct xhci_hcd *xhci, struct xhci_container_ctx *ctx);
struct xhci_ep_ctx *xhci_get_ep_ctx(struct xhci_hcd *xhci, struct xhci_container_ctx *ctx, unsigned int ep_index);
+/* xHCI sysfs interfaces */
+int xhci_sysfs_create_files(struct xhci_hcd *xhci);
+void xhci_sysfs_remove_files(struct xhci_hcd *xhci);
+
#endif /* __LINUX_XHCI_HCD_H */
--
2.1.4
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