| Paul Walmsley | 81fbc5ef | 2010-12-21 19:56:17 -0700 | [diff] [blame^] | 1 | /* |
| 2 | * OMAP2+ MPU WD_TIMER-specific code |
| 3 | * |
| 4 | * This program is free software; you can redistribute it and/or modify |
| 5 | * it under the terms of the GNU General Public License as published by |
| 6 | * the Free Software Foundation; either version 2 of the License, or |
| 7 | * (at your option) any later version. |
| 8 | */ |
| 9 | |
| 10 | #include <linux/kernel.h> |
| 11 | #include <linux/io.h> |
| 12 | #include <linux/err.h> |
| 13 | |
| 14 | #include <plat/omap_hwmod.h> |
| 15 | |
| 16 | /* |
| 17 | * In order to avoid any assumptions from bootloader regarding WDT |
| 18 | * settings, WDT module is reset during init. This enables the watchdog |
| 19 | * timer. Hence it is required to disable the watchdog after the WDT reset |
| 20 | * during init. Otherwise the system would reboot as per the default |
| 21 | * watchdog timer registers settings. |
| 22 | */ |
| 23 | #define OMAP_WDT_WPS 0x34 |
| 24 | #define OMAP_WDT_SPR 0x48 |
| 25 | |
| 26 | |
| 27 | int omap2_wd_timer_disable(struct omap_hwmod *oh) |
| 28 | { |
| 29 | void __iomem *base; |
| 30 | int ret; |
| 31 | |
| 32 | if (!oh) { |
| 33 | pr_err("%s: Could not look up wdtimer_hwmod\n", __func__); |
| 34 | return -EINVAL; |
| 35 | } |
| 36 | |
| 37 | base = omap_hwmod_get_mpu_rt_va(oh); |
| 38 | if (!base) { |
| 39 | pr_err("%s: Could not get the base address for %s\n", |
| 40 | oh->name, __func__); |
| 41 | return -EINVAL; |
| 42 | } |
| 43 | |
| 44 | /* Enable the clocks before accessing the WDT registers */ |
| 45 | ret = omap_hwmod_enable(oh); |
| 46 | if (ret) { |
| 47 | pr_err("%s: Could not enable clocks for %s\n", |
| 48 | oh->name, __func__); |
| 49 | return ret; |
| 50 | } |
| 51 | |
| 52 | /* sequence required to disable watchdog */ |
| 53 | __raw_writel(0xAAAA, base + OMAP_WDT_SPR); |
| 54 | while (__raw_readl(base + OMAP_WDT_WPS) & 0x10) |
| 55 | cpu_relax(); |
| 56 | |
| 57 | __raw_writel(0x5555, base + OMAP_WDT_SPR); |
| 58 | while (__raw_readl(base + OMAP_WDT_WPS) & 0x10) |
| 59 | cpu_relax(); |
| 60 | |
| 61 | ret = omap_hwmod_idle(oh); |
| 62 | if (ret) |
| 63 | pr_err("%s: Could not disable clocks for %s\n", |
| 64 | oh->name, __func__); |
| 65 | |
| 66 | return ret; |
| 67 | } |
| 68 | |