Hello.
Praveena Nadahally wrote:
From: Hans Petter Selasky <hans.petter.selasky@xxxxxxxxxxxxxx>
FIFOFLUSH is broken when a real packet is in the FIFO. This
hardware feature only works when the FIFO is empty.
The workaround described requires limiting the maximum
number of USB devices to 126, 128 - 2.
Signed-off-by: Hans Petter Selasky <hans.petter.selasky@xxxxxxxxxxxxxx>
Signed-off-by: Praveena Nadahally <praveen.nadahally@xxxxxxxxxxxxxx>
Acked-by: Linus Walleij <linus.walleij@xxxxxxxxxxxxxx>
---
drivers/usb/core/hub.c | 8 ++++--
drivers/usb/musb/musb_host.c | 45 +++++++++++++++++++++++++++++------------
2 files changed, 37 insertions(+), 16 deletions(-)
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 84c1897..83f1f50 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -1511,12 +1511,14 @@ static void choose_address(struct usb_device *udev)
* bus->devnum_next. */
devnum = find_next_zero_bit(bus->devmap.devicemap, 128,
bus->devnum_next);
- if (devnum >= 128)
+ /* Due to Hardware bugs we need to reserve a device address
+ * for flushing of endpoints. */
+ if (devnum >= 127)
devnum = find_next_zero_bit(bus->devmap.devicemap,
128, 1);
- bus->devnum_next = ( devnum >= 127 ? 1 : devnum + 1);
+ bus->devnum_next = devnum >= 126 ? 1 : devnum + 1;
}
- if (devnum < 128) {
+ if (devnum < 127) {
Oh, horror...
diff --git a/drivers/usb/musb/musb_host.c b/drivers/usb/musb/musb_host.c
index 877d20b..b14a5ff 100644
--- a/drivers/usb/musb/musb_host.c
+++ b/drivers/usb/musb/musb_host.c
@@ -106,24 +106,41 @@ static void musb_ep_program(struct musb *musb, u8 epnum,
static void musb_h_tx_flush_fifo(struct musb_hw_ep *ep)
{
void __iomem *epio = ep->regs;
+ void __iomem *regs = ep->musb->mregs;
u16 csr;
- u16 lastcsr = 0;
- int retries = 1000;
+ u8 addr;
+ int retries = 3000; /* 3ms */
+ /*
+ * NOTE: We are using a hack here because the FIFO-FLUSH
+ * bit is broken in hardware! The hack consists of changing
Broken on which version of MUSB core?
+ * the TXFUNCADDR to an unused device address and waiting
+ * for any pending USB packets to hit the 3-strikes and your
s/your/you're/
+ * gone rule.
+ */
+ addr = musb_readb(regs, MUSB_BUSCTL_OFFSET(ep->epnum, MUSB_TXFUNCADDR));
csr = musb_readw(epio, MUSB_TXCSR);
while (csr & MUSB_TXCSR_FIFONOTEMPTY) {
Besides, flushing is only documented to work when there's a full packet in
FIFO, so this condition should probably change...
- if (csr != lastcsr)
- DBG(3, "Host TX FIFONOTEMPTY csr: %02x\n", csr);
- lastcsr = csr;
- csr |= MUSB_TXCSR_FLUSHFIFO;
- musb_writew(epio, MUSB_TXCSR, csr);
+ musb_writeb(regs, MUSB_BUSCTL_OFFSET(ep->epnum,
+ MUSB_TXFUNCADDR), 127);
There's special macro for that write, musb_write_txfunaddr().
csr = musb_readw(epio, MUSB_TXCSR);
- if (WARN(retries-- < 1,
- "Could not flush host TX%d fifo: csr: %04x\n",
- ep->epnum, csr))
- return;
- mdelay(1);
+ retries--;
+ if (retries == 0) {
+ /* can happen if the USB clocks are OFF */
So what? Why you changed WARN() to DBG()?
+ DBG(3, "Could not flush host TX%d "
+ "fifo: csr=0x%04x\n", ep->epnum, csr);
+ break;
+ }
+ udelay(1);
}
+ /* clear any errors */
+ csr &= ~(MUSB_TXCSR_H_ERROR
+ | MUSB_TXCSR_H_RXSTALL
+ | MUSB_TXCSR_H_NAKTIMEOUT);
+ musb_writew(epio, MUSB_TXCSR, csr);
Why?
@@ -1141,7 +1158,9 @@ void musb_host_tx(struct musb *musb, u8 epnum)
DBG(3, "TX 3strikes on ep=%d\n", epnum);
status = -ETIMEDOUT;
-
+ } else if (tx_csr & MUSB_TXCSR_TXPKTRDY) {
+ /* BUSY - can happen during USB transfer cancel */
+ return;
Is this change somehow releated to yor proposed workaround?
WBR, Sergei
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