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usb: musb: core: fix TX/RX endpoint order

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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.

Cc: <stable@vger.kernel.org>
Signed-off-by: Felipe Balbi <balbi@ti.com>
This commit is contained in:
Felipe Balbi 2013-12-30 12:33:53 -06:00
parent d5638fcf15
commit e3c93e1a3f
1 changed files with 33 additions and 25 deletions
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58
drivers/usb/musb/musb_core.c
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@ -1597,16 +1597,30 @@ irqreturn_t musb_interrupt(struct musb *musb)
is_host_active(musb) ? "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);
/* "stage 1" is handling endpoint irqs */
/* handle endpoint 0 first */
if (musb->int_tx & 1) {
if (is_host_active(musb))
retval |= musb_h_ep0_irq(musb);
@ -1614,13 +1628,24 @@ irqreturn_t musb_interrupt(struct musb *musb)
retval |= musb_g_ep0_irq(musb);
}
/* RX on endpoints 1-15 */
reg = musb->int_tx >> 1;
ep_num = 1;
while (reg) {
if (reg & 1) {
retval = IRQ_HANDLED;
if (is_host_active(musb))
musb_host_tx(musb, ep_num);
else
musb_g_tx(musb, ep_num);
}
reg >>= 1;
ep_num++;
}
reg = musb->int_rx >> 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 (is_host_active(musb))
musb_host_rx(musb, ep_num);
@ -1632,23 +1657,6 @@ irqreturn_t musb_interrupt(struct musb *musb)
ep_num++;
}
/* TX on endpoints 1-15 */
reg = musb->int_tx >> 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 (is_host_active(musb))
musb_host_tx(musb, ep_num);
else
musb_g_tx(musb, ep_num);
}
reg >>= 1;
ep_num++;
}
return retval;
}
EXPORT_SYMBOL_GPL(musb_interrupt);