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usb: octeon-hcd: fail the probe when the USB core does not respond

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If the USBN clock/PHY setup did not actually bring the core up (wrong
board reference-clock configuration, for instance), every USBC CSR
reads as all-ones and initialization marches on programming garbage,
ending in timeouts or a wedge deep in the FIFO flush.

Read GHWCFG3 - a hardwired configuration register that can be neither
0 nor all-ones on a live core - right before core initialization, and
give up cleanly if the core is not answering.

Assisted-by: Claude:claude-opus-5
Signed-off-by: Orgad Shaneh <orgads@gmail.com>
Link: https://patch.msgid.link/20260901193100.1352110-2-orgads@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Orgad Shaneh 2026-09-01 19:30:28 +00:00 committed by Greg Kroah-Hartman
parent 4c7a1b9f1f
commit 22bce6d2b3
1 changed files with 8 additions and 0 deletions
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8
drivers/usb/host/octeon-hcd.c
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@ -853,6 +853,14 @@ static int cvmx_usb_initialize(struct device *dev,
* USBC_GAHBCFG[PTXFEMPLVL]
* Global interrupt mask, USBC_GAHBCFG[GLBLINTRMSK] = 1
*/
usbcx_gahbcfg.u32 = cvmx_usb_read_csr32(usb,
CVMX_USBCX_GHWCFG3(usb->index));
if (usbcx_gahbcfg.u32 == 0xffffffff || usbcx_gahbcfg.u32 == 0) {
dev_err(dev, "USB core is not responding (GHWCFG3=0x%08x)\n",
usbcx_gahbcfg.u32);
return -ENODEV;
}
usbcx_gahbcfg.u32 = 0;
usbcx_gahbcfg.s.dmaen = !(usb->init_flags &
CVMX_USB_INITIALIZE_FLAGS_NO_DMA);