From: Paul Walmsley Date: Tue, 14 Dec 2010 19:42:35 +0000 (-0700) Subject: OMAP2+: hwmod: add support for per-class custom device reset functions X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=bd36179eec2827cd60b4a8c6e180cc030c74a4ec;p=linux-beck.git OMAP2+: hwmod: add support for per-class custom device reset functions The standard omap_hwmod.c _reset() code relies on an IP block's OCP_SYSCONFIG.SOFTRESET register bit to reset the IP block. This works for most IP blocks on the chip, but unfortunately not all. For example, initiator-only IP blocks often don't have any MPU-accessible OCP-header registers, and therefore the MPU can't write to any OCP_SYSCONFIG registers in that block. Other IP blocks, such as the IVA and I2C, require a specialized reset sequence. Since we need to be able to reset these IP blocks as well, allow custom IP block reset functions to be passed into the hwmod code via a per-hwmod-class reset function pointer, struct omap_hwmod_class.reset. If .reset is non-null, then the hwmod _reset() code will call the custom function instead of the standard OCP SOFTRESET-based code. As part of this change, rename most of the existing _reset() function code to _ocp_softreset(), to indicate more clearly that it does not work for all cases. Signed-off-by: Paul Walmsley Cc: Benoît Cousson Cc: Paul Hunt Cc: Stanley Liu --- diff --git a/arch/arm/mach-omap2/omap_hwmod.c b/arch/arm/mach-omap2/omap_hwmod.c index 683428fa91f4..12a0b9a30a30 100644 --- a/arch/arm/mach-omap2/omap_hwmod.c +++ b/arch/arm/mach-omap2/omap_hwmod.c @@ -1089,7 +1089,7 @@ static int _read_hardreset(struct omap_hwmod *oh, const char *name) } /** - * _reset - reset an omap_hwmod + * _ocp_softreset - reset an omap_hwmod via the OCP_SYSCONFIG bit * @oh: struct omap_hwmod * * * Resets an omap_hwmod @oh via the OCP_SYSCONFIG bit. hwmod must be @@ -1098,12 +1098,13 @@ static int _read_hardreset(struct omap_hwmod *oh, const char *name) * the module did not reset in time, or 0 upon success. * * In OMAP3 a specific SYSSTATUS register is used to get the reset status. - * Starting in OMAP4, some IPs does not have SYSSTATUS register and instead + * Starting in OMAP4, some IPs do not have SYSSTATUS registers and instead * use the SYSCONFIG softreset bit to provide the status. * - * Note that some IP like McBSP does have a reset control but no reset status. + * Note that some IP like McBSP do have reset control but don't have + * reset status. */ -static int _reset(struct omap_hwmod *oh) +static int _ocp_softreset(struct omap_hwmod *oh) { u32 v; int c = 0; @@ -1124,7 +1125,7 @@ static int _reset(struct omap_hwmod *oh) if (oh->flags & HWMOD_CONTROL_OPT_CLKS_IN_RESET) _enable_optional_clocks(oh); - pr_debug("omap_hwmod: %s: resetting\n", oh->name); + pr_debug("omap_hwmod: %s: resetting via OCP SOFTRESET\n", oh->name); v = oh->_sysc_cache; ret = _set_softreset(oh, &v); @@ -1163,6 +1164,33 @@ dis_opt_clks: return ret; } +/** + * _reset - reset an omap_hwmod + * @oh: struct omap_hwmod * + * + * Resets an omap_hwmod @oh. The default software reset mechanism for + * most OMAP IP blocks is triggered via the OCP_SYSCONFIG.SOFTRESET + * bit. However, some hwmods cannot be reset via this method: some + * are not targets and therefore have no OCP header registers to + * access; others (like the IVA) have idiosyncratic reset sequences. + * So for these relatively rare cases, custom reset code can be + * supplied in the struct omap_hwmod_class .reset function pointer. + * Passes along the return value from either _reset() or the custom + * reset function - these must return -EINVAL if the hwmod cannot be + * reset this way or if the hwmod is in the wrong state, -ETIMEDOUT if + * the module did not reset in time, or 0 upon success. + */ +static int _reset(struct omap_hwmod *oh) +{ + int ret; + + pr_debug("omap_hwmod: %s: resetting\n", oh->name); + + ret = (oh->class->reset) ? oh->class->reset(oh) : _ocp_softreset(oh); + + return ret; +} + /** * _omap_hwmod_enable - enable an omap_hwmod * @oh: struct omap_hwmod * diff --git a/arch/arm/plat-omap/include/plat/omap_hwmod.h b/arch/arm/plat-omap/include/plat/omap_hwmod.h index b445ecdb95b8..e4c4fd4cc1ed 100644 --- a/arch/arm/plat-omap/include/plat/omap_hwmod.h +++ b/arch/arm/plat-omap/include/plat/omap_hwmod.h @@ -364,7 +364,7 @@ struct omap_hwmod_omap4_prcm { * when module is enabled, rather than the default, which is to * enable autoidle * HWMOD_SET_DEFAULT_CLOCKACT: program CLOCKACTIVITY bits at startup - * HWMOD_NO_IDLEST : this module does not have idle status - this is the case + * HWMOD_NO_IDLEST: this module does not have idle status - this is the case * only for few initiator modules on OMAP2 & 3. * HWMOD_CONTROL_OPT_CLKS_IN_RESET: Enable all optional clocks during reset. * This is needed for devices like DSS that require optional clocks enabled @@ -416,6 +416,7 @@ struct omap_hwmod_omap4_prcm { * @sysc: device SYSCONFIG/SYSSTATUS register data * @rev: revision of the IP class * @pre_shutdown: ptr to fn to be executed immediately prior to device shutdown + * @reset: ptr to fn to be executed in place of the standard hwmod reset fn * * Represent the class of a OMAP hardware "modules" (e.g. timer, * smartreflex, gpio, uart...) @@ -427,12 +428,18 @@ struct omap_hwmod_omap4_prcm { * or some negative error upon failure. Returning an error will cause * omap_hwmod_shutdown() to abort the device shutdown and return an * error. + * + * If @reset is defined, then the function it points to will be + * executed in place of the standard hwmod _reset() code in + * mach-omap2/omap_hwmod.c. This is needed for IP blocks which have + * unusual reset sequences - usually processor IP blocks like the IVA. */ struct omap_hwmod_class { const char *name; struct omap_hwmod_class_sysconfig *sysc; u32 rev; int (*pre_shutdown)(struct omap_hwmod *oh); + int (*reset)(struct omap_hwmod *oh); }; /**