usb: xhci: Add debugfs interface for xHCI driver

This adds debugfs consumer for xHCI driver. The debugfs entries
read all host registers, device/endpoint contexts, command ring,
event ring and various endpoint rings. With these entries, users
can check the registers and memory spaces used by a host during
run time, or save all the information with a simple 'cp -r' for
post-mortem programs.

The file hierarchy looks like this.

[root of debugfs]
|__usb
|____[e,u,o]hci                 <---------[root for other HCIs]
|____xhci                       <---------------[root for xHCI]
|______0000:00:14.0             <--------------[xHCI host name]
|________reg-cap                <--------[capability registers]
|________reg-op                 <-------[operational registers]
|________reg-runtime            <-----------[runtime registers]
|________reg-ext-#cap_name      <----[extended capability regs]
|________command-ring           <-------[root for command ring]
|__________cycle                <------------------[ring cycle]
|__________dequeue              <--------[ring dequeue pointer]
|__________enqueue              <--------[ring enqueue pointer]
|__________trbs                 <-------------------[ring trbs]
|________event-ring             <---------[root for event ring]
|__________cycle                <------------------[ring cycle]
|__________dequeue              <--------[ring dequeue pointer]
|__________enqueue              <--------[ring enqueue pointer]
|__________trbs                 <-------------------[ring trbs]
|________devices                <------------[root for devices]
|__________#slot_id             <-----------[root for a device]
|____________name               <-----------------[device name]
|____________slot-context       <----------------[slot context]
|____________ep-context         <-----------[endpoint contexts]
|____________ep#ep_index        <--------[root for an endpoint]
|______________cycle            <------------------[ring cycle]
|______________dequeue          <--------[ring dequeue pointer]
|______________enqueue          <--------[ring enqueue pointer]
|______________trbs             <-------------------[ring trbs]

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 9 insertions, 0 deletions

diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index ea176da627cd..ccf0ca3ed71e 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -131,6 +131,8 @@ struct xhci_cap_regs {
 /* Extended Capabilities pointer from PCI base - section 5.3.6 */
 #define HCC_EXT_CAPS(p)		XHCI_HCC_EXT_CAPS(p)
 
+#define CTX_SIZE(_hcc)		(HCC_64BYTE_CONTEXT(_hcc) ? 64 : 32)
+
 /* db_off bitmask - bits 0:1 reserved */
 #define	DBOFF_MASK	(~0x3)
 
@@ -1005,6 +1007,8 @@ struct xhci_virt_device {
 	struct xhci_tt_bw_info		*tt_info;
 	/* The current max exit latency for the enabled USB3 link states. */
 	u16				current_mel;
+	/* Used for the debugfs interfaces. */
+	void				*debugfs_private;
 };
 
 /*
@@ -1858,6 +1862,10 @@ struct xhci_hcd {
 /* Compliance Mode Timer Triggered every 2 seconds */
 #define COMP_MODE_RCVRY_MSECS 2000
 
+	struct dentry		*debugfs_root;
+	struct dentry		*debugfs_slots;
+	struct list_head	regset_list;
+
 	/* platform-specific data -- must come last */
 	unsigned long		priv[0] __aligned(sizeof(s64));
 };
@@ -2106,6 +2114,7 @@ struct xhci_ep_ctx *xhci_get_ep_ctx(struct xhci_hcd *xhci, struct xhci_container
 struct xhci_ring *xhci_triad_to_transfer_ring(struct xhci_hcd *xhci,
 		unsigned int slot_id, unsigned int ep_index,
 		unsigned int stream_id);
+
 static inline struct xhci_ring *xhci_urb_to_transfer_ring(struct xhci_hcd *xhci,
 								struct urb *urb)
 {