From d61a04bce69a9899f3f9e09917c407ae61635203 Mon Sep 17 00:00:00 2001 From: loos Date: Fri, 9 Jan 2015 03:32:51 +0000 Subject: [PATCH] MFC r276249: Fix the musb initialization sequence on AM335x. According to http://e2e.ti.com/support/arm/sitara_arm/f/791/t/210729 the USB reset pulse has an undocumented duration of 200ns and during this period the module must not be acessed. We wait for 100us to take into account for some imprecision of the early DELAY() loop. This fixes the eventual 'External Non-Linefetch Abort (S)' that happens at boot while resetting the musb subsystem. While here, enable the USB subsystem clock before the first access. git-svn-id: svn://svn.freebsd.org/base/stable/10@276877 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f --- sys/arm/ti/am335x/am335x_usbss.c | 27 ++++++++++++++++++--------- 1 file changed, 18 insertions(+), 9 deletions(-) diff --git a/sys/arm/ti/am335x/am335x_usbss.c b/sys/arm/ti/am335x/am335x_usbss.c index f1204f35e..0173922a1 100644 --- a/sys/arm/ti/am335x/am335x_usbss.c +++ b/sys/arm/ti/am335x/am335x_usbss.c @@ -288,21 +288,30 @@ musbotg_attach(device_t dev) return (ENXIO); } + /* Enable device clocks. */ + ti_prcm_clk_enable(MUSB0_CLK); + /* - * Reset USBSS, USB0 and USB1 + * Reset USBSS, USB0 and USB1. + * The registers of USB subsystem must not be accessed while the + * reset pulse is active (200ns). */ + USBSS_WRITE4(sc, USBSS_SYSCONFIG, USBSS_SYSCONFIG_SRESET); + DELAY(100); + i = 10; + while (USBSS_READ4(sc, USBSS_SYSCONFIG) & USBSS_SYSCONFIG_SRESET) { + DELAY(100); + if (i-- == 0) { + device_printf(dev, "reset timeout.\n"); + return (ENXIO); + } + } + + /* Read the module revision. */ rev = USBSS_READ4(sc, USBSS_REVREG); device_printf(dev, "TI AM335X USBSS v%d.%d.%d\n", (rev >> 8) & 7, (rev >> 6) & 3, rev & 63); - ti_prcm_clk_enable(MUSB0_CLK); - - USBSS_WRITE4(sc, USBSS_SYSCONFIG, - USBSS_SYSCONFIG_SRESET); - while (USBSS_READ4(sc, USBSS_SYSCONFIG) & - USBSS_SYSCONFIG_SRESET) - ; - err = bus_setup_intr(dev, sc->sc_irq_res[0], INTR_TYPE_BIO | INTR_MPSAFE, NULL, (driver_intr_t *)musbotg_usbss_interrupt, sc, -- 2.45.0