diff options
Diffstat (limited to 'arch/arm/mach-omap2/clock34xx.c')
| -rw-r--r-- | arch/arm/mach-omap2/clock34xx.c | 299 |
1 files changed, 295 insertions, 4 deletions
diff --git a/arch/arm/mach-omap2/clock34xx.c b/arch/arm/mach-omap2/clock34xx.c index b42bdd6079a..4263099b1ad 100644 --- a/arch/arm/mach-omap2/clock34xx.c +++ b/arch/arm/mach-omap2/clock34xx.c @@ -1,10 +1,11 @@ /* * OMAP3-specific clock framework functions * - * Copyright (C) 2007 Texas Instruments, Inc. - * Copyright (C) 2007 Nokia Corporation + * Copyright (C) 2007-2008 Texas Instruments, Inc. + * Copyright (C) 2007-2008 Nokia Corporation * * Written by Paul Walmsley + * Testing and integration fixes by Jouni Högander * * Parts of this code are based on code written by * Richard Woodruff, Tony Lindgren, Tuukka Tikkanen, Karthik Dasu @@ -23,6 +24,7 @@ #include <linux/delay.h> #include <linux/clk.h> #include <linux/io.h> +#include <linux/limits.h> #include <asm/arch/clock.h> #include <asm/arch/sram.h> @@ -37,8 +39,11 @@ #include "cm.h" #include "cm-regbits-34xx.h" -/* CM_CLKEN_PLL*.EN* bit values */ -#define DPLL_LOCKED 0x7 +/* CM_AUTOIDLE_PLL*.AUTO_* bit values */ +#define DPLL_AUTOIDLE_DISABLE 0x0 +#define DPLL_AUTOIDLE_LOW_POWER_STOP 0x1 + +#define MAX_DPLL_WAIT_TRIES 1000000 /** * omap3_dpll_recalc - recalculate DPLL rate @@ -53,6 +58,290 @@ static void omap3_dpll_recalc(struct clk *clk) propagate_rate(clk); } +/* _omap3_dpll_write_clken - write clken_bits arg to a DPLL's enable bits */ +static void _omap3_dpll_write_clken(struct clk *clk, u8 clken_bits) +{ + const struct dpll_data *dd; + + dd = clk->dpll_data; + + cm_rmw_reg_bits(dd->enable_mask, clken_bits << __ffs(dd->enable_mask), + dd->control_reg); +} + +/* _omap3_wait_dpll_status: wait for a DPLL to enter a specific state */ +static int _omap3_wait_dpll_status(struct clk *clk, u8 state) +{ + const struct dpll_data *dd; + int i = 0; + int ret = -EINVAL; + u32 idlest_mask; + + dd = clk->dpll_data; + + state <<= dd->idlest_bit; + idlest_mask = 1 << dd->idlest_bit; + + while (((cm_read_reg(dd->idlest_reg) & idlest_mask) != state) && + i < MAX_DPLL_WAIT_TRIES) { + i++; + udelay(1); + } + + if (i == MAX_DPLL_WAIT_TRIES) { + printk(KERN_ERR "clock: %s failed transition to '%s'\n", + clk->name, (state) ? "locked" : "bypassed"); + } else { + pr_debug("clock: %s transition to '%s' in %d loops\n", + clk->name, (state) ? "locked" : "bypassed", i); + + ret = 0; + } + + return ret; +} + +/* Non-CORE DPLL (e.g., DPLLs that do not control SDRC) clock functions */ + +/* + * _omap3_noncore_dpll_lock - instruct a DPLL to lock and wait for readiness + * @clk: pointer to a DPLL struct clk + * + * Instructs a non-CORE DPLL to lock. Waits for the DPLL to report + * readiness before returning. Will save and restore the DPLL's + * autoidle state across the enable, per the CDP code. If the DPLL + * locked successfully, return 0; if the DPLL did not lock in the time + * allotted, or DPLL3 was passed in, return -EINVAL. + */ +static int _omap3_noncore_dpll_lock(struct clk *clk) +{ + u8 ai; + int r; + + if (clk == &dpll3_ck) + return -EINVAL; + + pr_debug("clock: locking DPLL %s\n", clk->name); + + ai = omap3_dpll_autoidle_read(clk); + + _omap3_dpll_write_clken(clk, DPLL_LOCKED); + + if (ai) { + /* + * If no downstream clocks are enabled, CM_IDLEST bit + * may never become active, so don't wait for DPLL to lock. + */ + r = 0; + omap3_dpll_allow_idle(clk); + } else { + r = _omap3_wait_dpll_status(clk, 1); + omap3_dpll_deny_idle(clk); + }; + + return r; +} + +/* + * omap3_noncore_dpll_bypass - instruct a DPLL to bypass and wait for readiness + * @clk: pointer to a DPLL struct clk + * + * Instructs a non-CORE DPLL to enter low-power bypass mode. In + * bypass mode, the DPLL's rate is set equal to its parent clock's + * rate. Waits for the DPLL to report readiness before returning. + * Will save and restore the DPLL's autoidle state across the enable, + * per the CDP code. If the DPLL entered bypass mode successfully, + * return 0; if the DPLL did not enter bypass in the time allotted, or + * DPLL3 was passed in, or the DPLL does not support low-power bypass, + * return -EINVAL. + */ +static int _omap3_noncore_dpll_bypass(struct clk *clk) +{ + int r; + u8 ai; + + if (clk == &dpll3_ck) + return -EINVAL; + + if (!(clk->dpll_data->modes & (1 << DPLL_LOW_POWER_BYPASS))) + return -EINVAL; + + pr_debug("clock: configuring DPLL %s for low-power bypass\n", + clk->name); + + ai = omap3_dpll_autoidle_read(clk); + + _omap3_dpll_write_clken(clk, DPLL_LOW_POWER_BYPASS); + + r = _omap3_wait_dpll_status(clk, 0); + + if (ai) + omap3_dpll_allow_idle(clk); + else + omap3_dpll_deny_idle(clk); + + return r; +} + +/* + * _omap3_noncore_dpll_stop - instruct a DPLL to stop + * @clk: pointer to a DPLL struct clk + * + * Instructs a non-CORE DPLL to enter low-power stop. Will save and + * restore the DPLL's autoidle state across the stop, per the CDP + * code. If DPLL3 was passed in, or the DPLL does not support + * low-power stop, return -EINVAL; otherwise, return 0. + */ +static int _omap3_noncore_dpll_stop(struct clk *clk) +{ + u8 ai; + + if (clk == &dpll3_ck) + return -EINVAL; + + if (!(clk->dpll_data->modes & (1 << DPLL_LOW_POWER_STOP))) + return -EINVAL; + + pr_debug("clock: stopping DPLL %s\n", clk->name); + + ai = omap3_dpll_autoidle_read(clk); + + _omap3_dpll_write_clken(clk, DPLL_LOW_POWER_STOP); + + if (ai) + omap3_dpll_allow_idle(clk); + else + omap3_dpll_deny_idle(clk); + + return 0; +} + +/** + * omap3_noncore_dpll_enable - instruct a DPLL to enter bypass or lock mode + * @clk: pointer to a DPLL struct clk + * + * Instructs a non-CORE DPLL to enable, e.g., to enter bypass or lock. + * The choice of modes depends on the DPLL's programmed rate: if it is + * the same as the DPLL's parent clock, it will enter bypass; + * otherwise, it will enter lock. This code will wait for the DPLL to + * indicate readiness before returning, unless the DPLL takes too long + * to enter the target state. Intended to be used as the struct clk's + * enable function. If DPLL3 was passed in, or the DPLL does not + * support low-power stop, or if the DPLL took too long to enter + * bypass or lock, return -EINVAL; otherwise, return 0. + */ +static int omap3_noncore_dpll_enable(struct clk *clk) +{ + int r; + + if (clk == &dpll3_ck) + return -EINVAL; + + if (clk->parent->rate == clk_get_rate(clk)) + r = _omap3_noncore_dpll_bypass(clk); + else + r = _omap3_noncore_dpll_lock(clk); + + return r; +} + +/** + * omap3_noncore_dpll_enable - instruct a DPLL to enter bypass or lock mode + * @clk: pointer to a DPLL struct clk + * + * Instructs a non-CORE DPLL to enable, e.g., to enter bypass or lock. + * The choice of modes depends on the DPLL's programmed rate: if it is + * the same as the DPLL's parent clock, it will enter bypass; + * otherwise, it will enter lock. This code will wait for the DPLL to + * indicate readiness before returning, unless the DPLL takes too long + * to enter the target state. Intended to be used as the struct clk's + * enable function. If DPLL3 was passed in, or the DPLL does not + * support low-power stop, or if the DPLL took too long to enter + * bypass or lock, return -EINVAL; otherwise, return 0. + */ +static void omap3_noncore_dpll_disable(struct clk *clk) +{ + if (clk == &dpll3_ck) + return; + + _omap3_noncore_dpll_stop(clk); +} + +/** + * omap3_dpll_autoidle_read - read a DPLL's autoidle bits + * @clk: struct clk * of the DPLL to read + * + * Return the DPLL's autoidle bits, shifted down to bit 0. Returns + * -EINVAL if passed a null pointer or if the struct clk does not + * appear to refer to a DPLL. + */ +static u32 omap3_dpll_autoidle_read(struct clk *clk) +{ + const struct dpll_data *dd; + u32 v; + + if (!clk || !clk->dpll_data) + return -EINVAL; + + dd = clk->dpll_data; + + v = cm_read_reg(dd->autoidle_reg); + v &= dd->autoidle_mask; + v >>= __ffs(dd->autoidle_mask); + + return v; +} + +/** + * omap3_dpll_allow_idle - enable DPLL autoidle bits + * @clk: struct clk * of the DPLL to operate on + * + * Enable DPLL automatic idle control. This automatic idle mode + * switching takes effect only when the DPLL is locked, at least on + * OMAP3430. The DPLL will enter low-power stop when its downstream + * clocks are gated. No return value. + */ +static void omap3_dpll_allow_idle(struct clk *clk) +{ + const struct dpll_data *dd; + + if (!clk || !clk->dpll_data) + return; + + dd = clk->dpll_data; + + /* + * REVISIT: CORE DPLL can optionally enter low-power bypass + * by writing 0x5 instead of 0x1. Add some mechanism to + * optionally enter this mode. + */ + cm_rmw_reg_bits(dd->autoidle_mask, + DPLL_AUTOIDLE_LOW_POWER_STOP << __ffs(dd->autoidle_mask), + dd->autoidle_reg); +} + +/** + * omap3_dpll_deny_idle - prevent DPLL from automatically idling + * @clk: struct clk * of the DPLL to operate on + * + * Disable DPLL automatic idle control. No return value. + */ +static void omap3_dpll_deny_idle(struct clk *clk) +{ + const struct dpll_data *dd; + + if (!clk || !clk->dpll_data) + return; + + dd = clk->dpll_data; + + cm_rmw_reg_bits(dd->autoidle_mask, + DPLL_AUTOIDLE_DISABLE << __ffs(dd->autoidle_mask), + dd->autoidle_reg); +} + +/* Clock control for DPLL outputs */ + /** * omap3_clkoutx2_recalc - recalculate DPLL X2 output virtual clock rate * @clk: DPLL output struct clk @@ -89,6 +378,8 @@ static void omap3_clkoutx2_recalc(struct clk *clk) propagate_rate(clk); } +/* Common clock code */ + /* * As it is structured now, this will prevent an OMAP2/3 multiboot * kernel from compiling. This will need further attention. |