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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>
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1 changed files with 15 additions and 12 deletions
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@ -28,18 +28,21 @@ static struct omap_ehci *const ehci = (struct omap_ehci *)OMAP_EHCI_BASE;
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static int omap_uhh_reset(void)
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{
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unsigned long init = get_timer(0);
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/* perform UHH soft reset, and wait until reset is complete */
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writel(OMAP_UHH_SYSCONFIG_SOFTRESET, &uhh->sysc);
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/* Wait for UHH reset to complete */
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while (!(readl(&uhh->syss) & OMAP_UHH_SYSSTATUS_EHCI_RESETDONE))
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if (get_timer(init) > CONFIG_SYS_HZ) {
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debug("OMAP UHH error: timeout resetting ehci\n");
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return -EL3RST;
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}
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/*
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* Soft resetting the UHH module causes instability issues on
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* all OMAPs so we just avoid it.
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*
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* See OMAP36xx Errata
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* i571: USB host EHCI may stall when entering smart-standby mode
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* i660: USBHOST Configured In Smart-Idle Can Lead To a Deadlock
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*
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* On OMAP4/5, soft-resetting the UHH module will put it into
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* Smart-Idle mode and lead to a deadlock.
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*
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* On OMAP3, this doesn't seem to be the case but still instabilities
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* are observed on beagle (3530 ES1.0) if soft-reset is used.
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* e.g. NFS root failures with Linux kernel.
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*/
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return 0;
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}
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