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Commit 815e173e authored by Jason Wessel's avatar Jason Wessel Committed by Greg Kroah-Hartman
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USB: ehci-dbgp: split PID register updates for IN and OUT pipes 



This patch addresses two problems:

1) Bulk reads should always use the DATA0 for the pid, and the write
   PID should toggle between DATA0 and DATA1.  The fix is using
   dbgp_pid_write_update() and dbgp_pid_read_update().

2) The delay loop for waiting for a transaction was not long enough to
   always complete the initial handshake inside dbgp_wait_until_done().
   After the initial handshake the maximum delay length is never reached.

The combined result of these two changes allows for the removal of the
forced resynchronization where a bulk write was issued with a dummy
data payload only to get the device to start accepting data writes
again.

CC: Eric Biederman <ebiederm@xmission.com>
CC: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: default avatarJason Wessel <jason.wessel@windriver.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 52720983

drivers/usb/early/ehci-dbgp.c

+28 −40
Original line number Diff line number Diff line
@@ -66,8 +66,6 @@ static struct ehci_dev ehci_dev; 


#define USB_DEBUG_DEVNUM 127



#define DBGP_DATA_TOGGLE	0x8800



#ifdef DBGP_DEBUG

#define dbgp_printk printk

static void dbgp_ehci_status(char *str)
@@ -88,11 +86,6 @@ static inline void dbgp_ehci_status(char *str) { } 
static inline void dbgp_printk(const char *fmt, ...) { }

#endif



static inline u32 dbgp_pid_update(u32 x, u32 tok)

{

	return ((x ^ DBGP_DATA_TOGGLE) & 0xffff00) | (tok & 0xff);

}



static inline u32 dbgp_len_update(u32 x, u32 len)

{

	return (x & ~0x0f) | (len & 0x0f);
@@ -136,6 +129,19 @@ static inline u32 dbgp_len_update(u32 x, u32 len) 


#define DBGP_MAX_PACKET		8

#define DBGP_TIMEOUT		(250 * 1000)

#define DBGP_LOOPS		1000



static inline u32 dbgp_pid_write_update(u32 x, u32 tok)

{

	static int data0 = USB_PID_DATA1;

	data0 ^= USB_PID_DATA_TOGGLE;

	return (x & 0xffff0000) | (data0 << 8) | (tok & 0xff);

}



static inline u32 dbgp_pid_read_update(u32 x, u32 tok)

{

	return (x & 0xffff0000) | (USB_PID_DATA0 << 8) | (tok & 0xff);

}



static int dbgp_wait_until_complete(void)

{
@@ -180,7 +186,7 @@ static int dbgp_wait_until_done(unsigned ctrl) 
{

	u32 pids, lpid;

	int ret;

	int loop = 3;

	int loop = DBGP_LOOPS;



retry:

	writel(ctrl | DBGP_GO, &ehci_debug->control);
@@ -197,6 +203,8 @@ retry: 
		 */

		if (ret == -DBGP_TIMEOUT && !dbgp_not_safe)

			dbgp_not_safe = 1;

		if (ret == -DBGP_ERR_BAD && --loop > 0)

			goto retry;

		return ret;

	}
@@ -245,12 +253,20 @@ static inline void dbgp_get_data(void *buf, int size) 
		bytes[i] = (hi >> (8*(i - 4))) & 0xff;

}



static int dbgp_out(u32 addr, const char *bytes, int size)

static int dbgp_bulk_write(unsigned devnum, unsigned endpoint,

			 const char *bytes, int size)

{

	int ret;

	u32 addr;

	u32 pids, ctrl;



	if (size > DBGP_MAX_PACKET)

		return -1;



	addr = DBGP_EPADDR(devnum, endpoint);



	pids = readl(&ehci_debug->pids);

	pids = dbgp_pid_update(pids, USB_PID_OUT);

	pids = dbgp_pid_write_update(pids, USB_PID_OUT);



	ctrl = readl(&ehci_debug->control);

	ctrl = dbgp_len_update(ctrl, size);
@@ -260,34 +276,7 @@ static int dbgp_out(u32 addr, const char *bytes, int size) 
	dbgp_set_data(bytes, size);

	writel(addr, &ehci_debug->address);

	writel(pids, &ehci_debug->pids);

	return dbgp_wait_until_done(ctrl);

}



static int dbgp_bulk_write(unsigned devnum, unsigned endpoint,

			 const char *bytes, int size)

{

	int ret;

	int loops = 5;

	u32 addr;

	if (size > DBGP_MAX_PACKET)

		return -1;



	addr = DBGP_EPADDR(devnum, endpoint);

try_again:

	if (loops--) {

		ret = dbgp_out(addr, bytes, size);

		if (ret == -DBGP_ERR_BAD) {

			int try_loops = 3;

			do {

				/* Emit a dummy packet to re-sync communication

				 * with the debug device */

				if (dbgp_out(addr, "12345678", 8) >= 0) {

					udelay(2);

					goto try_again;

				}

			} while (try_loops--);

		}

	}

	ret = dbgp_wait_until_done(ctrl);



	return ret;

}
@@ -304,7 +293,7 @@ static int dbgp_bulk_read(unsigned devnum, unsigned endpoint, void *data, 
	addr = DBGP_EPADDR(devnum, endpoint);



	pids = readl(&ehci_debug->pids);

	pids = dbgp_pid_update(pids, USB_PID_IN);

	pids = dbgp_pid_read_update(pids, USB_PID_IN);



	ctrl = readl(&ehci_debug->control);

	ctrl = dbgp_len_update(ctrl, size);
@@ -362,7 +351,6 @@ static int dbgp_control_msg(unsigned devnum, int requesttype, 
	return dbgp_bulk_read(devnum, 0, data, size);

}





/* Find a PCI capability */

static u32 __init find_cap(u32 num, u32 slot, u32 func, int cap)

{