diff options
| author | Roger Quadros <rogerq@ti.com> | 2013-07-22 11:14:37 +0300 |
|---|---|---|
| committer | Marek Vasut <marex@denx.de> | 2013-07-29 23:01:33 +0200 |
| commit | bb1f327d0a6ec9236c172fdc0912ace7c8e2ea83 (patch) | |
| tree | 42f6b251bc45a37381da496f4947abdd4932f596 /drivers/usb | |
| parent | 6bed7ce569fc409843ff2537937ea1b5fd0f694d (diff) | |
usb: ehci-omap: Don't softreset USB High-speed Host (UHH) Module
Fixes NFS root problems with Beagle (3530 ES1.0) when used with
external USB-ethernet adapter and "USB start" command used within
u-boot.
Soft resetting the UHH module causes instability issues on
all OMAPs so we just avoid it.
See OMAP36xx Errata
i571: USB host EHCI may stall when entering smart-standby mode
i660: USBHOST Configured In Smart-Idle Can Lead To a Deadlock
On OMAP4/5, soft-resetting the UHH module can put it into
Smart-Idle mode and lead to a deadlock.
On OMAP3 this doesn't seem to be the case but still instabilities
are observed on beagle (3530 ES1.0) if soft-reset is used.
e.g. NFS root failures with Linux kernel.
Signed-off-by: Roger Quadros <rogerq@ti.com>
Diffstat (limited to 'drivers/usb')
| -rw-r--r-- | drivers/usb/host/ehci-omap.c | 27 |
1 files changed, 15 insertions, 12 deletions
diff --git a/drivers/usb/host/ehci-omap.c b/drivers/usb/host/ehci-omap.c index a47e078f62..032d5e5ec2 100644 --- a/drivers/usb/host/ehci-omap.c +++ b/drivers/usb/host/ehci-omap.c @@ -28,18 +28,21 @@ static struct omap_ehci *const ehci = (struct omap_ehci *)OMAP_EHCI_BASE; static int omap_uhh_reset(void) { - unsigned long init = get_timer(0); - - /* perform UHH soft reset, and wait until reset is complete */ - writel(OMAP_UHH_SYSCONFIG_SOFTRESET, &uhh->sysc); - - /* Wait for UHH reset to complete */ - while (!(readl(&uhh->syss) & OMAP_UHH_SYSSTATUS_EHCI_RESETDONE)) - if (get_timer(init) > CONFIG_SYS_HZ) { - debug("OMAP UHH error: timeout resetting ehci\n"); - return -EL3RST; - } - +/* + * Soft resetting the UHH module causes instability issues on + * all OMAPs so we just avoid it. + * + * See OMAP36xx Errata + * i571: USB host EHCI may stall when entering smart-standby mode + * i660: USBHOST Configured In Smart-Idle Can Lead To a Deadlock + * + * On OMAP4/5, soft-resetting the UHH module will put it into + * Smart-Idle mode and lead to a deadlock. + * + * On OMAP3, this doesn't seem to be the case but still instabilities + * are observed on beagle (3530 ES1.0) if soft-reset is used. + * e.g. NFS root failures with Linux kernel. + */ return 0; } |