diff options
Diffstat (limited to 'arch/arm/mach-omap2/clockdomain.c')
| -rw-r--r-- | arch/arm/mach-omap2/clockdomain.c | 623 |
1 files changed, 623 insertions, 0 deletions
diff --git a/arch/arm/mach-omap2/clockdomain.c b/arch/arm/mach-omap2/clockdomain.c new file mode 100644 index 000000000000..4c3ce9cfd948 --- /dev/null +++ b/arch/arm/mach-omap2/clockdomain.c @@ -0,0 +1,623 @@ +/* + * OMAP2/3 clockdomain framework functions + * + * Copyright (C) 2008 Texas Instruments, Inc. + * Copyright (C) 2008 Nokia Corporation + * + * Written by Paul Walmsley and Jouni Högander + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ +#ifdef CONFIG_OMAP_DEBUG_CLOCKDOMAIN +# define DEBUG +#endif + +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/device.h> +#include <linux/list.h> +#include <linux/errno.h> +#include <linux/delay.h> +#include <linux/clk.h> +#include <linux/limits.h> + +#include <linux/io.h> + +#include <linux/bitops.h> + +#include <mach/clock.h> + +#include "prm.h" +#include "prm-regbits-24xx.h" +#include "cm.h" + +#include <mach/powerdomain.h> +#include <mach/clockdomain.h> + +/* clkdm_list contains all registered struct clockdomains */ +static LIST_HEAD(clkdm_list); + +/* clkdm_mutex protects clkdm_list add and del ops */ +static DEFINE_MUTEX(clkdm_mutex); + +/* array of powerdomain deps to be added/removed when clkdm in hwsup mode */ +static struct clkdm_pwrdm_autodep *autodeps; + + +/* Private functions */ + +/* + * _autodep_lookup - resolve autodep pwrdm names to pwrdm pointers; store + * @autodep: struct clkdm_pwrdm_autodep * to resolve + * + * Resolve autodep powerdomain names to powerdomain pointers via + * pwrdm_lookup() and store the pointers in the autodep structure. An + * "autodep" is a powerdomain sleep/wakeup dependency that is + * automatically added and removed whenever clocks in the associated + * clockdomain are enabled or disabled (respectively) when the + * clockdomain is in hardware-supervised mode. Meant to be called + * once at clockdomain layer initialization, since these should remain + * fixed for a particular architecture. No return value. + */ +static void _autodep_lookup(struct clkdm_pwrdm_autodep *autodep) +{ + struct powerdomain *pwrdm; + + if (!autodep) + return; + + if (!omap_chip_is(autodep->omap_chip)) + return; + + pwrdm = pwrdm_lookup(autodep->pwrdm_name); + if (!pwrdm) { + pr_debug("clockdomain: _autodep_lookup: powerdomain %s " + "does not exist\n", autodep->pwrdm_name); + WARN_ON(1); + return; + } + autodep->pwrdm = pwrdm; + + return; +} + +/* + * _clkdm_add_autodeps - add auto sleepdeps/wkdeps to clkdm upon clock enable + * @clkdm: struct clockdomain * + * + * Add the "autodep" sleep & wakeup dependencies to clockdomain 'clkdm' + * in hardware-supervised mode. Meant to be called from clock framework + * when a clock inside clockdomain 'clkdm' is enabled. No return value. + */ +static void _clkdm_add_autodeps(struct clockdomain *clkdm) +{ + struct clkdm_pwrdm_autodep *autodep; + + for (autodep = autodeps; autodep->pwrdm_name; autodep++) { + if (!autodep->pwrdm) + continue; + + pr_debug("clockdomain: adding %s sleepdep/wkdep for " + "pwrdm %s\n", autodep->pwrdm_name, + clkdm->pwrdm->name); + + pwrdm_add_sleepdep(clkdm->pwrdm, autodep->pwrdm); + pwrdm_add_wkdep(clkdm->pwrdm, autodep->pwrdm); + } +} + +/* + * _clkdm_add_autodeps - remove auto sleepdeps/wkdeps from clkdm + * @clkdm: struct clockdomain * + * + * Remove the "autodep" sleep & wakeup dependencies from clockdomain 'clkdm' + * in hardware-supervised mode. Meant to be called from clock framework + * when a clock inside clockdomain 'clkdm' is disabled. No return value. + */ +static void _clkdm_del_autodeps(struct clockdomain *clkdm) +{ + struct clkdm_pwrdm_autodep *autodep; + + for (autodep = autodeps; autodep->pwrdm_name; autodep++) { + if (!autodep->pwrdm) + continue; + + pr_debug("clockdomain: removing %s sleepdep/wkdep for " + "pwrdm %s\n", autodep->pwrdm_name, + clkdm->pwrdm->name); + + pwrdm_del_sleepdep(clkdm->pwrdm, autodep->pwrdm); + pwrdm_del_wkdep(clkdm->pwrdm, autodep->pwrdm); + } +} + + +static struct clockdomain *_clkdm_lookup(const char *name) +{ + struct clockdomain *clkdm, *temp_clkdm; + + if (!name) + return NULL; + + clkdm = NULL; + + list_for_each_entry(temp_clkdm, &clkdm_list, node) { + if (!strcmp(name, temp_clkdm->name)) { + clkdm = temp_clkdm; + break; + } + } + + return clkdm; +} + + +/* Public functions */ + +/** + * clkdm_init - set up the clockdomain layer + * @clkdms: optional pointer to an array of clockdomains to register + * @init_autodeps: optional pointer to an array of autodeps to register + * + * Set up internal state. If a pointer to an array of clockdomains + * was supplied, loop through the list of clockdomains, register all + * that are available on the current platform. Similarly, if a + * pointer to an array of clockdomain-powerdomain autodependencies was + * provided, register those. No return value. + */ +void clkdm_init(struct clockdomain **clkdms, + struct clkdm_pwrdm_autodep *init_autodeps) +{ + struct clockdomain **c = NULL; + struct clkdm_pwrdm_autodep *autodep = NULL; + + if (clkdms) + for (c = clkdms; *c; c++) + clkdm_register(*c); + + autodeps = init_autodeps; + if (autodeps) + for (autodep = autodeps; autodep->pwrdm_name; autodep++) + _autodep_lookup(autodep); +} + +/** + * clkdm_register - register a clockdomain + * @clkdm: struct clockdomain * to register + * + * Adds a clockdomain to the internal clockdomain list. + * Returns -EINVAL if given a null pointer, -EEXIST if a clockdomain is + * already registered by the provided name, or 0 upon success. + */ +int clkdm_register(struct clockdomain *clkdm) +{ + int ret = -EINVAL; + struct powerdomain *pwrdm; + + if (!clkdm || !clkdm->name) + return -EINVAL; + + if (!omap_chip_is(clkdm->omap_chip)) + return -EINVAL; + + pwrdm = pwrdm_lookup(clkdm->pwrdm_name); + if (!pwrdm) { + pr_debug("clockdomain: clkdm_register %s: powerdomain %s " + "does not exist\n", clkdm->name, clkdm->pwrdm_name); + return -EINVAL; + } + clkdm->pwrdm = pwrdm; + + mutex_lock(&clkdm_mutex); + /* Verify that the clockdomain is not already registered */ + if (_clkdm_lookup(clkdm->name)) { + ret = -EEXIST; + goto cr_unlock; + }; + + list_add(&clkdm->node, &clkdm_list); + + pwrdm_add_clkdm(pwrdm, clkdm); + + pr_debug("clockdomain: registered %s\n", clkdm->name); + ret = 0; + +cr_unlock: + mutex_unlock(&clkdm_mutex); + + return ret; +} + +/** + * clkdm_unregister - unregister a clockdomain + * @clkdm: struct clockdomain * to unregister + * + * Removes a clockdomain from the internal clockdomain list. Returns + * -EINVAL if clkdm argument is NULL. + */ +int clkdm_unregister(struct clockdomain *clkdm) +{ + if (!clkdm) + return -EINVAL; + + pwrdm_del_clkdm(clkdm->pwrdm, clkdm); + + mutex_lock(&clkdm_mutex); + list_del(&clkdm->node); + mutex_unlock(&clkdm_mutex); + + pr_debug("clockdomain: unregistered %s\n", clkdm->name); + + return 0; +} + +/** + * clkdm_lookup - look up a clockdomain by name, return a pointer + * @name: name of clockdomain + * + * Find a registered clockdomain by its name. Returns a pointer to the + * struct clockdomain if found, or NULL otherwise. + */ +struct clockdomain *clkdm_lookup(const char *name) +{ + struct clockdomain *clkdm, *temp_clkdm; + + if (!name) + return NULL; + + clkdm = NULL; + + mutex_lock(&clkdm_mutex); + list_for_each_entry(temp_clkdm, &clkdm_list, node) { + if (!strcmp(name, temp_clkdm->name)) { + clkdm = temp_clkdm; + break; + } + } + mutex_unlock(&clkdm_mutex); + + return clkdm; +} + +/** + * clkdm_for_each - call function on each registered clockdomain + * @fn: callback function * + * + * Call the supplied function for each registered clockdomain. + * The callback function can return anything but 0 to bail + * out early from the iterator. The callback function is called with + * the clkdm_mutex held, so no clockdomain structure manipulation + * functions should be called from the callback, although hardware + * clockdomain control functions are fine. Returns the last return + * value of the callback function, which should be 0 for success or + * anything else to indicate failure; or -EINVAL if the function pointer + * is null. + */ +int clkdm_for_each(int (*fn)(struct clockdomain *clkdm)) +{ + struct clockdomain *clkdm; + int ret = 0; + + if (!fn) + return -EINVAL; + + mutex_lock(&clkdm_mutex); + list_for_each_entry(clkdm, &clkdm_list, node) { + ret = (*fn)(clkdm); + if (ret) + break; + } + mutex_unlock(&clkdm_mutex); + + return ret; +} + + +/** + * clkdm_get_pwrdm - return a ptr to the pwrdm that this clkdm resides in + * @clkdm: struct clockdomain * + * + * Return a pointer to the struct powerdomain that the specified clockdomain + * 'clkdm' exists in, or returns NULL if clkdm argument is NULL. + */ +struct powerdomain *clkdm_get_pwrdm(struct clockdomain *clkdm) +{ + if (!clkdm) + return NULL; + + return clkdm->pwrdm; +} + + +/* Hardware clockdomain control */ + +/** + * omap2_clkdm_clktrctrl_read - read the clkdm's current state transition mode + * @clk: struct clk * of a clockdomain + * + * Return the clockdomain's current state transition mode from the + * corresponding domain CM_CLKSTCTRL register. Returns -EINVAL if clk + * is NULL or the current mode upon success. + */ +static int omap2_clkdm_clktrctrl_read(struct clockdomain *clkdm) +{ + u32 v; + + if (!clkdm) + return -EINVAL; + + v = cm_read_mod_reg(clkdm->pwrdm->prcm_offs, CM_CLKSTCTRL); + v &= clkdm->clktrctrl_mask; + v >>= __ffs(clkdm->clktrctrl_mask); + + return v; +} + +/** + * omap2_clkdm_sleep - force clockdomain sleep transition + * @clkdm: struct clockdomain * + * + * Instruct the CM to force a sleep transition on the specified + * clockdomain 'clkdm'. Returns -EINVAL if clk is NULL or if + * clockdomain does not support software-initiated sleep; 0 upon + * success. + */ +int omap2_clkdm_sleep(struct clockdomain *clkdm) +{ + if (!clkdm) + return -EINVAL; + + if (!(clkdm->flags & CLKDM_CAN_FORCE_SLEEP)) { + pr_debug("clockdomain: %s does not support forcing " + "sleep via software\n", clkdm->name); + return -EINVAL; + } + + pr_debug("clockdomain: forcing sleep on %s\n", clkdm->name); + + if (cpu_is_omap24xx()) { + + cm_set_mod_reg_bits(OMAP24XX_FORCESTATE, + clkdm->pwrdm->prcm_offs, PM_PWSTCTRL); + + } else if (cpu_is_omap34xx()) { + + u32 v = (OMAP34XX_CLKSTCTRL_FORCE_SLEEP << + __ffs(clkdm->clktrctrl_mask)); + + cm_rmw_mod_reg_bits(clkdm->clktrctrl_mask, v, + clkdm->pwrdm->prcm_offs, CM_CLKSTCTRL); + + } else { + BUG(); + }; + + return 0; +} + +/** + * omap2_clkdm_wakeup - force clockdomain wakeup transition + * @clkdm: struct clockdomain * + * + * Instruct the CM to force a wakeup transition on the specified + * clockdomain 'clkdm'. Returns -EINVAL if clkdm is NULL or if the + * clockdomain does not support software-controlled wakeup; 0 upon + * success. + */ +int omap2_clkdm_wakeup(struct clockdomain *clkdm) +{ + if (!clkdm) + return -EINVAL; + + if (!(clkdm->flags & CLKDM_CAN_FORCE_WAKEUP)) { + pr_debug("clockdomain: %s does not support forcing " + "wakeup via software\n", clkdm->name); + return -EINVAL; + } + + pr_debug("clockdomain: forcing wakeup on %s\n", clkdm->name); + + if (cpu_is_omap24xx()) { + + cm_clear_mod_reg_bits(OMAP24XX_FORCESTATE, + clkdm->pwrdm->prcm_offs, PM_PWSTCTRL); + + } else if (cpu_is_omap34xx()) { + + u32 v = (OMAP34XX_CLKSTCTRL_FORCE_WAKEUP << + __ffs(clkdm->clktrctrl_mask)); + + cm_rmw_mod_reg_bits(clkdm->clktrctrl_mask, v, + clkdm->pwrdm->prcm_offs, CM_CLKSTCTRL); + + } else { + BUG(); + }; + + return 0; +} + +/** + * omap2_clkdm_allow_idle - enable hwsup idle transitions for clkdm + * @clkdm: struct clockdomain * + * + * Allow the hardware to automatically switch the clockdomain into + * active or idle states, as needed by downstream clocks. If the + * clockdomain has any downstream clocks enabled in the clock + * framework, wkdep/sleepdep autodependencies are added; this is so + * device drivers can read and write to the device. No return value. + */ +void omap2_clkdm_allow_idle(struct clockdomain *clkdm) +{ + u32 v; + + if (!clkdm) + return; + + if (!(clkdm->flags & CLKDM_CAN_ENABLE_AUTO)) { + pr_debug("clock: automatic idle transitions cannot be enabled " + "on clockdomain %s\n", clkdm->name); + return; + } + + pr_debug("clockdomain: enabling automatic idle transitions for %s\n", + clkdm->name); + + if (atomic_read(&clkdm->usecount) > 0) + _clkdm_add_autodeps(clkdm); + + if (cpu_is_omap24xx()) + v = OMAP24XX_CLKSTCTRL_ENABLE_AUTO; + else if (cpu_is_omap34xx()) + v = OMAP34XX_CLKSTCTRL_ENABLE_AUTO; + else + BUG(); + + + cm_rmw_mod_reg_bits(clkdm->clktrctrl_mask, + v << __ffs(clkdm->clktrctrl_mask), + clkdm->pwrdm->prcm_offs, + CM_CLKSTCTRL); +} + +/** + * omap2_clkdm_deny_idle - disable hwsup idle transitions for clkdm + * @clkdm: struct clockdomain * + * + * Prevent the hardware from automatically switching the clockdomain + * into inactive or idle states. If the clockdomain has downstream + * clocks enabled in the clock framework, wkdep/sleepdep + * autodependencies are removed. No return value. + */ +void omap2_clkdm_deny_idle(struct clockdomain *clkdm) +{ + u32 v; + + if (!clkdm) + return; + + if (!(clkdm->flags & CLKDM_CAN_DISABLE_AUTO)) { + pr_debug("clockdomain: automatic idle transitions cannot be " + "disabled on %s\n", clkdm->name); + return; + } + + pr_debug("clockdomain: disabling automatic idle transitions for %s\n", + clkdm->name); + + if (cpu_is_omap24xx()) + v = OMAP24XX_CLKSTCTRL_DISABLE_AUTO; + else if (cpu_is_omap34xx()) + v = OMAP34XX_CLKSTCTRL_DISABLE_AUTO; + else + BUG(); + + cm_rmw_mod_reg_bits(clkdm->clktrctrl_mask, + v << __ffs(clkdm->clktrctrl_mask), + clkdm->pwrdm->prcm_offs, CM_CLKSTCTRL); + + if (atomic_read(&clkdm->usecount) > 0) + _clkdm_del_autodeps(clkdm); +} + + +/* Clockdomain-to-clock framework interface code */ + +/** + * omap2_clkdm_clk_enable - add an enabled downstream clock to this clkdm + * @clkdm: struct clockdomain * + * @clk: struct clk * of the enabled downstream clock + * + * Increment the usecount of this clockdomain 'clkdm' and ensure that + * it is awake. Intended to be called by clk_enable() code. If the + * clockdomain is in software-supervised idle mode, force the + * clockdomain to wake. If the clockdomain is in hardware-supervised + * idle mode, add clkdm-pwrdm autodependencies, to ensure that devices + * in the clockdomain can be read from/written to by on-chip processors. + * Returns -EINVAL if passed null pointers; returns 0 upon success or + * if the clockdomain is in hwsup idle mode. + */ +int omap2_clkdm_clk_enable(struct clockdomain *clkdm, struct clk *clk) +{ + int v; + + /* + * XXX Rewrite this code to maintain a list of enabled + * downstream clocks for debugging purposes? + */ + + if (!clkdm || !clk) + return -EINVAL; + + if (atomic_inc_return(&clkdm->usecount) > 1) + return 0; + + /* Clockdomain now has one enabled downstream clock */ + + pr_debug("clockdomain: clkdm %s: clk %s now enabled\n", clkdm->name, + clk->name); + + v = omap2_clkdm_clktrctrl_read(clkdm); + + if ((cpu_is_omap34xx() && v == OMAP34XX_CLKSTCTRL_ENABLE_AUTO) || + (cpu_is_omap24xx() && v == OMAP24XX_CLKSTCTRL_ENABLE_AUTO)) + _clkdm_add_autodeps(clkdm); + else + omap2_clkdm_wakeup(clkdm); + + return 0; +} + +/** + * omap2_clkdm_clk_disable - remove an enabled downstream clock from this clkdm + * @clkdm: struct clockdomain * + * @clk: struct clk * of the disabled downstream clock + * + * Decrement the usecount of this clockdomain 'clkdm'. Intended to be + * called by clk_disable() code. If the usecount goes to 0, put the + * clockdomain to sleep (software-supervised mode) or remove the + * clkdm-pwrdm autodependencies (hardware-supervised mode). Returns + * -EINVAL if passed null pointers; -ERANGE if the clkdm usecount + * underflows and debugging is enabled; or returns 0 upon success or + * if the clockdomain is in hwsup idle mode. + */ +int omap2_clkdm_clk_disable(struct clockdomain *clkdm, struct clk *clk) +{ + int v; + + /* + * XXX Rewrite this code to maintain a list of enabled + * downstream clocks for debugging purposes? + */ + + if (!clkdm || !clk) + return -EINVAL; + +#ifdef DEBUG + if (atomic_read(&clkdm->usecount) == 0) { + WARN_ON(1); /* underflow */ + return -ERANGE; + } +#endif + + if (atomic_dec_return(&clkdm->usecount) > 0) + return 0; + + /* All downstream clocks of this clockdomain are now disabled */ + + pr_debug("clockdomain: clkdm %s: clk %s now disabled\n", clkdm->name, + clk->name); + + v = omap2_clkdm_clktrctrl_read(clkdm); + + if ((cpu_is_omap34xx() && v == OMAP34XX_CLKSTCTRL_ENABLE_AUTO) || + (cpu_is_omap24xx() && v == OMAP24XX_CLKSTCTRL_ENABLE_AUTO)) + _clkdm_del_autodeps(clkdm); + else + omap2_clkdm_sleep(clkdm); + + return 0; +} + |