[PATCH 3.4 006/146] usb: musb: core: fix TX/RX endpoint order

lizf
2015-09-15T09:05:39Z

From: Felipe Balbi <balbi@ti.com>

3.4.109-rc1 review patch. If anyone has any objections, please let me know.

------------------

commit e3c93e1a3f35be4cf1493d3ccfb0c6d9209e4922 upstream.

As per Mentor Graphics' documentation, we should
always handle TX endpoints before RX endpoints.

This patch fixes that error while also updating
some hard-to-read comments which were scattered
around musb_interrupt().

This patch should be backported as far back as
possible since this error has been in the driver
since it's conception.

Signed-off-by: Felipe Balbi <balbi@ti.com>
[lizf: Backported to 3.4: adjust context]
Signed-off-by: Zefan Li <lizefan@huawei.com>
---
drivers/usb/musb/musb_core.c | 44 ++++++++++++++++++++++++++------------------
1 file changed, 26 insertions(+), 18 deletions(-)

diff --git a/drivers/usb/musb/musb_core.c b/drivers/usb/musb/musb_core.c
index a2b4008..d3481c4 100644
--- a/drivers/usb/musb/musb_core.c
+++ b/drivers/usb/musb/musb_core.c
@@ -1544,16 +1544,30 @@ irqreturn_t musb_interrupt(struct musb *musb)
(devctl & MUSB_DEVCTL_HM) ? "host" : "peripheral",
musb->int_usb, musb->int_tx, musb->int_rx);

- /* the core can interrupt us for multiple reasons; docs have
- * a generic interrupt flowchart to follow
+ /**
+ * According to Mentor Graphics' documentation, flowchart on page 98,
+ * IRQ should be handled as follows:
+ *
+ * . Resume IRQ
+ * . Session Request IRQ
+ * . VBUS Error IRQ
+ * . Suspend IRQ
+ * . Connect IRQ
+ * . Disconnect IRQ
+ * . Reset/Babble IRQ
+ * . SOF IRQ (we're not using this one)
+ * . Endpoint 0 IRQ
+ * . TX Endpoints
+ * . RX Endpoints
+ *
+ * We will be following that flowchart in order to avoid any problems
+ * that might arise with internal Finite State Machine.
*/
+
if (musb->int_usb)
retval |= musb_stage0_irq(musb, musb->int_usb,
devctl, power);

- /* "stage 1" is handling endpoint irqs */
-
- /* handle endpoint 0 first */
if (musb->int_tx & 1) {
if (devctl & MUSB_DEVCTL_HM)
retval |= musb_h_ep0_irq(musb);
@@ -1561,43 +1575,37 @@ irqreturn_t musb_interrupt(struct musb *musb)
retval |= musb_g_ep0_irq(musb);
}

- /* RX on endpoints 1-15 */
- reg = musb->int_rx >> 1;
+ reg = musb->int_tx >> 1;
ep_num = 1;
while (reg) {
if (reg & 1) {
- /* musb_ep_select(musb->mregs, ep_num); */
- /* REVISIT just retval = ep->rx_irq(...) */
retval = IRQ_HANDLED;
if (devctl & MUSB_DEVCTL_HM) {
if (is_host_capable())
- musb_host_rx(musb, ep_num);
+ musb_host_tx(musb, ep_num);
} else {
if (is_peripheral_capable())
- musb_g_rx(musb, ep_num);
+ musb_g_tx(musb, ep_num);
}
}
-
reg >>= 1;
ep_num++;
}

- /* TX on endpoints 1-15 */
- reg = musb->int_tx >> 1;
+ reg = musb->int_rx >> 1;
ep_num = 1;
while (reg) {
if (reg & 1) {
- /* musb_ep_select(musb->mregs, ep_num); */
- /* REVISIT just retval |= ep->tx_irq(...) */
retval = IRQ_HANDLED;
if (devctl & MUSB_DEVCTL_HM) {
if (is_host_capable())
- musb_host_tx(musb, ep_num);
+ musb_host_rx(musb, ep_num);
} else {
if (is_peripheral_capable())
- musb_g_tx(musb, ep_num);
+ musb_g_rx(musb, ep_num);
}
}
+
reg >>= 1;
ep_num++;
}
--
1.9.1