Got pxa27x_udc working on the pxa320 Nomad platform. The
problem was that the pxa3xx UDC is not quite compatible with
the pxa27x UDC in how it handles back-to-back control
packets. The pxa27x probably drops them by default, but the
pxa320 does not, and you have to detect it and set the OPC
bit to clear the zero-length packet.
Signed-off-by: Aric Blumer <aric@xxxxxxxxxxxxxx>
Signed-off-by: Robert Jarzmik <robert.jarzmik@xxxxxxx>
---
drivers/usb/gadget/Kconfig | 2 +-
drivers/usb/gadget/pxa27x_udc.c | 13 ++++++++++++-
2 files changed, 13 insertions(+), 2 deletions(-)
diff --git a/drivers/usb/gadget/Kconfig b/drivers/usb/gadget/Kconfig
index 080bb1e..772dd3b 100644
--- a/drivers/usb/gadget/Kconfig
+++ b/drivers/usb/gadget/Kconfig
@@ -253,7 +253,7 @@ config USB_PXA25X_SMALL
config USB_GADGET_PXA27X
boolean "PXA 27x"
- depends on ARCH_PXA && PXA27x
+ depends on ARCH_PXA && (PXA27x || PXA3xx)
select USB_OTG_UTILS
help
Intel's PXA 27x series XScale ARM v5TE processors include
diff --git a/drivers/usb/gadget/pxa27x_udc.c b/drivers/usb/gadget/pxa27x_udc.c
index ffe6e0a..51790b0 100644
--- a/drivers/usb/gadget/pxa27x_udc.c
+++ b/drivers/usb/gadget/pxa27x_udc.c
@@ -1892,6 +1892,15 @@ static void handle_ep0_ctrl_req(struct pxa_udc *udc,
nuke(ep, -EPROTO);
+ /*
+ * In the PXA320 manual, in the section about Back-to-Back setup
+ * packets, it describes this situation. The solution is to set OPC to
+ * get rid of the status packet, and then continue with the setup
+ * packet. Generalize to pxa27x CPUs.
+ */
+ if (epout_has_pkt(ep) && (ep_count_bytes_remain(ep) == 0))
+ udc_ep_writel(ep, UDCCSR, UDCCSR0_OPC);
+
/* read SETUP packet */
for (i = 0; i < 2; i++) {
if (unlikely(ep_is_empty(ep)))
@@ -1965,6 +1974,8 @@ stall:
* cleared by software.
* - clearing UDCCSR0_OPC always flushes ep0. If in setup stage, never do it
* before reading ep0.
+ * This is true only for PXA27x. This is not true anymore for PXA3xx family
+ * (check Back-to-Back setup packet in developers guide).
* - irq can be called on a "packet complete" event (opc_irq=1), while
* UDCCSR0_OPC is not yet raised (delta can be as big as 100ms
* from experimentation).
@@ -2575,7 +2586,7 @@ static struct platform_driver udc_driver = {
static int __init udc_init(void)
{
- if (!cpu_is_pxa27x())
+ if (!cpu_is_pxa27x() && !cpu_is_pxa3xx())
return -ENODEV;
printk(KERN_INFO "%s: version %s\n", driver_name, DRIVER_VERSION);
--
1.6.2.1
--
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