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 <bige...@linutronix.de>
---
drivers/usb/musb/musb_core.c | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)
diff --git a/drivers/usb/musb/musb_core.c b/drivers/usb/musb/musb_core.c
index 13a8d0e..84a46b5 100644
--- a/drivers/usb/musb/musb_core.c
+++ b/drivers/usb/musb/musb_core.c
@@ -437,12 +437,12 @@ 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.
@@ -455,6 +455,7 @@ 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:
@@ -462,6 +463,7 @@ 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;
@@ -625,8 +627,8 @@ 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) {
@@ -1530,12 +1532,11 @@ 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",
@@ -1546,7 +1547,7 @@ 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 */
--
1.7.10.4
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