usb: musb: Perform only write access on MUSB_INTRRXE
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 16bit read access to MUSB_INTRRXE results in an 32bit read
access which also reads INTRUSB and therefore may lose interrupts.
This patch uses a shadow register of MUSB_INTRRXE so we only perform
write access to it.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Felipe Balbi <balbi@ti.com>
diff --git a/drivers/usb/musb/musb_core.c b/drivers/usb/musb/musb_core.c
index d156fe8..7ff1986 100644
--- a/drivers/usb/musb/musb_core.c
+++ b/drivers/usb/musb/musb_core.c
@@ -725,7 +725,8 @@
/* REVISIT HNP; just force disconnect */
}
musb_writew(musb->mregs, MUSB_INTRTXE, musb->epmask);
- musb_writew(musb->mregs, MUSB_INTRRXE, musb->epmask & 0xfffe);
+ musb->intrrxe = musb->epmask & 0xfffe;
+ musb_writew(musb->mregs, MUSB_INTRRXE, musb->intrrxe);
musb_writeb(musb->mregs, MUSB_INTRUSBE, 0xf7);
musb->port1_status &= ~(USB_PORT_STAT_LOW_SPEED
|USB_PORT_STAT_HIGH_SPEED
@@ -947,7 +948,8 @@
/* Set INT enable registers, enable interrupts */
musb_writew(regs, MUSB_INTRTXE, musb->epmask);
- musb_writew(regs, MUSB_INTRRXE, musb->epmask & 0xfffe);
+ musb->intrrxe = musb->epmask & 0xfffe;
+ musb_writew(regs, MUSB_INTRRXE, musb->intrrxe);
musb_writeb(regs, MUSB_INTRUSBE, 0xf7);
musb_writeb(regs, MUSB_TESTMODE, 0);
@@ -986,6 +988,7 @@
/* disable interrupts */
musb_writeb(mbase, MUSB_INTRUSBE, 0);
musb_writew(mbase, MUSB_INTRTXE, 0);
+ musb->intrrxe = 0;
musb_writew(mbase, MUSB_INTRRXE, 0);
/* off */
@@ -2122,7 +2125,6 @@
musb->context.busctl = musb_read_ulpi_buscontrol(musb->mregs);
musb->context.power = musb_readb(musb_base, MUSB_POWER);
musb->context.intrtxe = musb_readw(musb_base, MUSB_INTRTXE);
- musb->context.intrrxe = musb_readw(musb_base, MUSB_INTRRXE);
musb->context.intrusbe = musb_readb(musb_base, MUSB_INTRUSBE);
musb->context.index = musb_readb(musb_base, MUSB_INDEX);
musb->context.devctl = musb_readb(musb_base, MUSB_DEVCTL);
@@ -2196,7 +2198,7 @@
musb_write_ulpi_buscontrol(musb->mregs, musb->context.busctl);
musb_writeb(musb_base, MUSB_POWER, musb->context.power);
musb_writew(musb_base, MUSB_INTRTXE, musb->context.intrtxe);
- musb_writew(musb_base, MUSB_INTRRXE, musb->context.intrrxe);
+ musb_writew(musb_base, MUSB_INTRRXE, musb->intrrxe);
musb_writeb(musb_base, MUSB_INTRUSBE, musb->context.intrusbe);
musb_writeb(musb_base, MUSB_DEVCTL, musb->context.devctl);