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usb: musb: read MUSB_POWER register only when required.

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This is part of the workaround for AM35x advisory Advisory 1.1.20.
The advisory says that the IPSS bridge can't handle 8 & 16 bit read
access. An 8bit read access to MUSB_POWER results in an 32bit read
access which also reads INTRTX and therefore may lose interrupts.
This patch tries to minimize reads to MUSB_POWER and perform them only
when required.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Felipe Balbi <balbi@ti.com>
This commit is contained in:
Sebastian Andrzej Siewior 2012-10-30 19:52:23 +01:00 committed by Felipe Balbi
parent 4b0de6f383
commit b11e94d037
1 changed files with 8 additions and 7 deletions
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15
drivers/usb/musb/musb_core.c
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@ -467,12 +467,12 @@ void musb_hnp_stop(struct musb *musb)
*/
static irqreturn_t musb_stage0_irq(struct musb *musb, u8 int_usb,
u8 devctl, u8 power)
u8 devctl)
{
struct usb_otg *otg = musb->xceiv->otg;
irqreturn_t handled = IRQ_NONE;
dev_dbg(musb->controller, "<== Power=%02x, DevCtl=%02x, int_usb=0x%x\n", power, devctl,
dev_dbg(musb->controller, "<== DevCtl=%02x, int_usb=0x%x\n", devctl,
int_usb);
/* in host mode, the peripheral may issue remote wakeup.
@ -485,6 +485,7 @@ static irqreturn_t musb_stage0_irq(struct musb *musb, u8 int_usb,
if (devctl & MUSB_DEVCTL_HM) {
void __iomem *mbase = musb->mregs;
u8 power;
switch (musb->xceiv->state) {
case OTG_STATE_A_SUSPEND:
@ -492,6 +493,7 @@ static irqreturn_t musb_stage0_irq(struct musb *musb, u8 int_usb,
* will stop RESUME signaling
*/
power = musb_readb(musb->mregs, MUSB_POWER);
if (power & MUSB_POWER_SUSPENDM) {
/* spurious */
musb->int_usb &= ~MUSB_INTR_SUSPEND;
@ -655,8 +657,8 @@ static irqreturn_t musb_stage0_irq(struct musb *musb, u8 int_usb,
}
if (int_usb & MUSB_INTR_SUSPEND) {
dev_dbg(musb->controller, "SUSPEND (%s) devctl %02x power %02x\n",
otg_state_string(musb->xceiv->state), devctl, power);
dev_dbg(musb->controller, "SUSPEND (%s) devctl %02x\n",
otg_state_string(musb->xceiv->state), devctl);
handled = IRQ_HANDLED;
switch (musb->xceiv->state) {
@ -1560,12 +1562,11 @@ static irqreturn_t generic_interrupt(int irq, void *__hci)
irqreturn_t musb_interrupt(struct musb *musb)
{
irqreturn_t retval = IRQ_NONE;
u8 devctl, power;
u8 devctl;
int ep_num;
u32 reg;
devctl = musb_readb(musb->mregs, MUSB_DEVCTL);
power = musb_readb(musb->mregs, MUSB_POWER);
dev_dbg(musb->controller, "** IRQ %s usb%04x tx%04x rx%04x\n",
(devctl & MUSB_DEVCTL_HM) ? "host" : "peripheral",
@ -1576,7 +1577,7 @@ irqreturn_t musb_interrupt(struct musb *musb)
*/
if (musb->int_usb)
retval |= musb_stage0_irq(musb, musb->int_usb,
devctl, power);
devctl);
/* "stage 1" is handling endpoint irqs */