diff options
| author | Catalin Marinas <catalin.marinas@arm.com> | 2009-03-23 12:38:16 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2009-03-24 16:20:46 -0700 |
| commit | e6bdfe36e52f0e552b50acf49a82851eeb122fde (patch) | |
| tree | 42dcc7d86734cb10a9f8010ceb9ec4f54698229d | |
| parent | b7af0bb26899bb47ae16fb41d2296111b0784a56 (diff) | |
USB: isp1760: Add a delay before reading the SKIPMAP registers in isp1760-hcd.c
The data read from the SKIPMAP registers is not immediately available
after writing and the driver panics when a packet is enqueued from the
interrupt handler. This patch adds an ndelay(195) before these registers
are read (delay value mentioned in section 15.1.1.3 of the ISP1760 data
sheet).
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| -rw-r--r-- | drivers/usb/host/isp1760-hcd.c | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/drivers/usb/host/isp1760-hcd.c b/drivers/usb/host/isp1760-hcd.c index 3172c0fd2a6..cd07ea3f0c6 100644 --- a/drivers/usb/host/isp1760-hcd.c +++ b/drivers/usb/host/isp1760-hcd.c @@ -819,6 +819,13 @@ static void enqueue_an_ATL_packet(struct usb_hcd *hcd, struct isp1760_qh *qh, u32 atl_regs, payload; u32 buffstatus; + /* + * When this function is called from the interrupt handler to enqueue + * a follow-up packet, the SKIP register gets written and read back + * almost immediately. With ISP1761, this register requires a delay of + * 195ns between a write and subsequent read (see section 15.1.1.3). + */ + ndelay(195); skip_map = isp1760_readl(hcd->regs + HC_ATL_PTD_SKIPMAP_REG); BUG_ON(!skip_map); @@ -853,6 +860,13 @@ static void enqueue_an_INT_packet(struct usb_hcd *hcd, struct isp1760_qh *qh, u32 int_regs, payload; u32 buffstatus; + /* + * When this function is called from the interrupt handler to enqueue + * a follow-up packet, the SKIP register gets written and read back + * almost immediately. With ISP1761, this register requires a delay of + * 195ns between a write and subsequent read (see section 15.1.1.3). + */ + ndelay(195); skip_map = isp1760_readl(hcd->regs + HC_INT_PTD_SKIPMAP_REG); BUG_ON(!skip_map); |