diff options
author | Paul Walmsley <paul@pwsan.com> | 2010-05-19 04:40:24 +0400 |
---|---|---|
committer | Paul Walmsley <paul@pwsan.com> | 2010-05-20 22:31:06 +0400 |
commit | 435699db6a3d81bfd36d25150177399a4f6048d5 (patch) | |
tree | f6fa03a580c900178ea6b2b0c64e9272460d3cd3 | |
parent | d74b4949714741f4c58cd1801a6a92737b89a61c (diff) | |
download | linux-435699db6a3d81bfd36d25150177399a4f6048d5.tar.xz |
OMAP2+ clock: clean up clkt_clksel.c
This patch cleans up arch/arm/mach-omap2/clkt_clksel.c. It:
- makes several functions static that are not called outside the file;
- adds documentation;
- makes some code paths easier to read (hopefully), by breaking up
compound statements and removing redundant checks;
- converts some pr_err()s that indicate clock tree data problems into WARN()s,
so they are more likely to be noticed;
- and moves omap2_clk_round_rate() back into mach-omap2/clock.c, its proper
home, since it is not clksel-specific.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
-rw-r--r-- | arch/arm/mach-omap2/clkt_clksel.c | 423 | ||||
-rw-r--r-- | arch/arm/mach-omap2/clock.c | 9 | ||||
-rw-r--r-- | arch/arm/mach-omap2/clock.h | 11 |
3 files changed, 266 insertions, 177 deletions
diff --git a/arch/arm/mach-omap2/clkt_clksel.c b/arch/arm/mach-omap2/clkt_clksel.c index 9a23aebeea7e..a781cd6795a4 100644 --- a/arch/arm/mach-omap2/clkt_clksel.c +++ b/arch/arm/mach-omap2/clkt_clksel.c @@ -12,8 +12,26 @@ * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * - * XXX At some point these clksel clocks should be split into - * "divider" clocks and "mux" clocks to better match the hardware. + * + * clksel clocks are clocks that do not have a fixed parent, or that + * can divide their parent's rate, or possibly both at the same time, based + * on the contents of a hardware register bitfield. + * + * All of the various mux and divider settings can be encoded into + * struct clksel* data structures, and then these can be autogenerated + * from some hardware database for each new chip generation. This + * should avoid the need to write, review, and validate a lot of new + * clock code for each new chip, since it can be exported from the SoC + * design flow. This is now done on OMAP4. + * + * The fusion of mux and divider clocks is a software creation. In + * hardware reality, the multiplexer (parent selection) and the + * divider exist separately. XXX At some point these clksel clocks + * should be split into "divider" clocks and "mux" clocks to better + * match the hardware. + * + * (The name "clksel" comes from the name of the corresponding + * register field in the OMAP2/3 family of SoCs.) * * XXX Currently these clocks are only used in the OMAP2/3/4 code, but * many of the OMAP1 clocks should be convertible to use this @@ -29,14 +47,11 @@ #include <plat/clock.h> #include "clock.h" -#include "cm.h" -#include "cm-regbits-24xx.h" -#include "cm-regbits-34xx.h" /* Private functions */ /** - * _omap2_get_clksel_by_parent - return clksel struct for a given clk & parent + * _get_clksel_by_parent() - return clksel struct for a given clk & parent * @clk: OMAP struct clk ptr to inspect * @src_clk: OMAP struct clk ptr of the parent clk to search for * @@ -44,23 +59,19 @@ * the element associated with the supplied parent clock address. * Returns a pointer to the struct clksel on success or NULL on error. */ -static const struct clksel *_omap2_get_clksel_by_parent(struct clk *clk, - struct clk *src_clk) +static const struct clksel *_get_clksel_by_parent(struct clk *clk, + struct clk *src_clk) { const struct clksel *clks; - if (!clk->clksel) - return NULL; - - for (clks = clk->clksel; clks->parent; clks++) { + for (clks = clk->clksel; clks->parent; clks++) if (clks->parent == src_clk) break; /* Found the requested parent */ - } if (!clks->parent) { - printk(KERN_ERR "clock: Could not find parent clock %s in " - "clksel array of clock %s\n", src_clk->name, - clk->name); + /* This indicates a data problem */ + WARN(1, "clock: Could not find parent clock %s in clksel array " + "of clock %s\n", src_clk->name, clk->name); return NULL; } @@ -68,7 +79,7 @@ static const struct clksel *_omap2_get_clksel_by_parent(struct clk *clk, } /** - * _omap2_clksel_get_src_field - find the new clksel divisor to use + * _get_div_and_fieldval() - find the new clksel divisor and field value to use * @src_clk: planned new parent struct clk * * @clk: struct clk * that is being reparented * @field_val: pointer to a u32 to contain the register data for the divisor @@ -82,14 +93,14 @@ static const struct clksel *_omap2_get_clksel_by_parent(struct clk *clk, * success (in this latter case, the corresponding register bitfield * value is passed back in the variable pointed to by @field_val) */ -static u8 _omap2_clksel_get_src_field(struct clk *src_clk, struct clk *clk, - u32 *field_val) +static u8 _get_div_and_fieldval(struct clk *src_clk, struct clk *clk, + u32 *field_val) { const struct clksel *clks; const struct clksel_rate *clkr, *max_clkr; u8 max_div = 0; - clks = _omap2_get_clksel_by_parent(clk, src_clk); + clks = _get_clksel_by_parent(clk, src_clk); if (!clks) return 0; @@ -113,9 +124,9 @@ static u8 _omap2_clksel_get_src_field(struct clk *src_clk, struct clk *clk, } if (max_div == 0) { - WARN(1, "clock: Could not find divisor for " - "clock %s parent %s\n", clk->name, - src_clk->parent->name); + /* This indicates an error in the clksel data */ + WARN(1, "clock: Could not find divisor for clock %s parent %s" + "\n", clk->name, src_clk->parent->name); return 0; } @@ -124,82 +135,141 @@ static u8 _omap2_clksel_get_src_field(struct clk *src_clk, struct clk *clk, return max_div; } +/** + * _write_clksel_reg() - program a clock's clksel register in hardware + * @clk: struct clk * to program + * @v: clksel bitfield value to program (with LSB at bit 0) + * + * Shift the clksel register bitfield value @v to its appropriate + * location in the clksel register and write it in. This function + * will ensure that the write to the clksel_reg reaches its + * destination before returning -- important since PRM and CM register + * accesses can be quite slow compared to ARM cycles -- but does not + * take into account any time the hardware might take to switch the + * clock source. + */ +static void _write_clksel_reg(struct clk *clk, u32 field_val) +{ + u32 v; -/* Public functions */ + v = __raw_readl(clk->clksel_reg); + v &= ~clk->clksel_mask; + v |= field_val << __ffs(clk->clksel_mask); + __raw_writel(v, clk->clksel_reg); + + v = __raw_readl(clk->clksel_reg); /* OCP barrier */ +} /** - * omap2_init_clksel_parent - set a clksel clk's parent field from the hardware - * @clk: OMAP clock struct ptr to use + * _clksel_to_divisor() - turn clksel field value into integer divider + * @clk: OMAP struct clk to use + * @field_val: register field value to find * - * Given a pointer to a source-selectable struct clk, read the hardware - * register and determine what its parent is currently set to. Update the - * clk->parent field with the appropriate clk ptr. + * Given a struct clk of a rate-selectable clksel clock, and a register field + * value to search for, find the corresponding clock divisor. The register + * field value should be pre-masked and shifted down so the LSB is at bit 0 + * before calling. Returns 0 on error or returns the actual integer divisor + * upon success. */ -void omap2_init_clksel_parent(struct clk *clk) +static u32 _clksel_to_divisor(struct clk *clk, u32 field_val) { const struct clksel *clks; const struct clksel_rate *clkr; - u32 r, found = 0; - if (!clk->clksel) - return; + clks = _get_clksel_by_parent(clk, clk->parent); + if (!clks) + return 0; - r = __raw_readl(clk->clksel_reg) & clk->clksel_mask; - r >>= __ffs(clk->clksel_mask); + for (clkr = clks->rates; clkr->div; clkr++) { + if (!(clkr->flags & cpu_mask)) + continue; - for (clks = clk->clksel; clks->parent && !found; clks++) { - for (clkr = clks->rates; clkr->div && !found; clkr++) { - if ((clkr->flags & cpu_mask) && (clkr->val == r)) { - if (clk->parent != clks->parent) { - pr_debug("clock: inited %s parent " - "to %s (was %s)\n", - clk->name, clks->parent->name, - ((clk->parent) ? - clk->parent->name : "NULL")); - clk_reparent(clk, clks->parent); - }; - found = 1; - } - } + if (clkr->val == field_val) + break; } - if (!found) - printk(KERN_ERR "clock: init parent: could not find " - "regval %0x for clock %s\n", r, clk->name); + if (!clkr->div) { + /* This indicates a data error */ + WARN(1, "clock: Could not find fieldval %d for clock %s parent " + "%s\n", field_val, clk->name, clk->parent->name); + return 0; + } - return; + return clkr->div; } -/* - * Used for clocks that are part of CLKSEL_xyz governed clocks. - * REVISIT: Maybe change to use clk->enable() functions like on omap1? +/** + * _divisor_to_clksel() - turn clksel integer divisor into a field value + * @clk: OMAP struct clk to use + * @div: integer divisor to search for + * + * Given a struct clk of a rate-selectable clksel clock, and a clock + * divisor, find the corresponding register field value. Returns the + * register field value _before_ left-shifting (i.e., LSB is at bit + * 0); or returns 0xFFFFFFFF (~0) upon error. */ -unsigned long omap2_clksel_recalc(struct clk *clk) +static u32 _divisor_to_clksel(struct clk *clk, u32 div) { - unsigned long rate; - u32 div = 0; + const struct clksel *clks; + const struct clksel_rate *clkr; - pr_debug("clock: recalc'ing clksel clk %s\n", clk->name); + /* should never happen */ + WARN_ON(div == 0); - div = omap2_clksel_get_divisor(clk); - if (div == 0) - return clk->rate; + clks = _get_clksel_by_parent(clk, clk->parent); + if (!clks) + return ~0; - rate = clk->parent->rate / div; + for (clkr = clks->rates; clkr->div; clkr++) { + if (!(clkr->flags & cpu_mask)) + continue; - pr_debug("clock: new clock rate is %ld (div %d)\n", rate, div); + if (clkr->div == div) + break; + } - return rate; + if (!clkr->div) { + pr_err("clock: Could not find divisor %d for clock %s parent " + "%s\n", div, clk->name, clk->parent->name); + return ~0; + } + + return clkr->val; } /** - * omap2_clksel_round_rate_div - find divisor for the given clock and rate + * _read_divisor() - get current divisor applied to parent clock (from hdwr) + * @clk: OMAP struct clk to use. + * + * Read the current divisor register value for @clk that is programmed + * into the hardware, convert it into the actual divisor value, and + * return it; or return 0 on error. + */ +static u32 _read_divisor(struct clk *clk) +{ + u32 v; + + if (!clk->clksel || !clk->clksel_mask) + return 0; + + v = __raw_readl(clk->clksel_reg); + v &= clk->clksel_mask; + v >>= __ffs(clk->clksel_mask); + + return _clksel_to_divisor(clk, v); +} + +/* Public functions */ + +/** + * omap2_clksel_round_rate_div() - find divisor for the given clock and rate * @clk: OMAP struct clk to use * @target_rate: desired clock rate * @new_div: ptr to where we should store the divisor * * Finds 'best' divider value in an array based on the source and target * rates. The divider array must be sorted with smallest divider first. + * This function is also used by the DPLL3 M2 divider code. * * Returns the rounded clock rate or returns 0xffffffff on error. */ @@ -211,12 +281,15 @@ u32 omap2_clksel_round_rate_div(struct clk *clk, unsigned long target_rate, const struct clksel_rate *clkr; u32 last_div = 0; + if (!clk->clksel || !clk->clksel_mask) + return ~0; + pr_debug("clock: clksel_round_rate_div: %s target_rate %ld\n", clk->name, target_rate); *new_div = 1; - clks = _omap2_get_clksel_by_parent(clk, clk->parent); + clks = _get_clksel_by_parent(clk, clk->parent); if (!clks) return ~0; @@ -252,168 +325,174 @@ u32 omap2_clksel_round_rate_div(struct clk *clk, unsigned long target_rate, return clk->parent->rate / clkr->div; } -/** - * omap2_clksel_round_rate - find rounded rate for the given clock and rate - * @clk: OMAP struct clk to use - * @target_rate: desired clock rate - * - * Compatibility wrapper for OMAP clock framework - * Finds best target rate based on the source clock and possible dividers. - * rates. The divider array must be sorted with smallest divider first. - * Note that this will not work for clocks which are part of CONFIG_PARTICIPANT, - * they are only settable as part of virtual_prcm set. - * - * Returns the rounded clock rate or returns 0xffffffff on error. +/* + * Clocktype interface functions to the OMAP clock code + * (i.e., those used in struct clk field function pointers, etc.) */ -long omap2_clksel_round_rate(struct clk *clk, unsigned long target_rate) -{ - u32 new_div; - - return omap2_clksel_round_rate_div(clk, target_rate, &new_div); -} - - -/* Given a clock and a rate apply a clock specific rounding function */ -long omap2_clk_round_rate(struct clk *clk, unsigned long rate) -{ - if (clk->round_rate) - return clk->round_rate(clk, rate); - - return clk->rate; -} /** - * omap2_clksel_to_divisor() - turn clksel field value into integer divider - * @clk: OMAP struct clk to use - * @field_val: register field value to find + * omap2_init_clksel_parent() - set a clksel clk's parent field from the hdwr + * @clk: OMAP clock struct ptr to use * - * Given a struct clk of a rate-selectable clksel clock, and a register field - * value to search for, find the corresponding clock divisor. The register - * field value should be pre-masked and shifted down so the LSB is at bit 0 - * before calling. Returns 0 on error + * Given a pointer @clk to a source-selectable struct clk, read the + * hardware register and determine what its parent is currently set + * to. Update @clk's .parent field with the appropriate clk ptr. No + * return value. */ -u32 omap2_clksel_to_divisor(struct clk *clk, u32 field_val) +void omap2_init_clksel_parent(struct clk *clk) { const struct clksel *clks; const struct clksel_rate *clkr; + u32 r, found = 0; - clks = _omap2_get_clksel_by_parent(clk, clk->parent); - if (!clks) - return 0; + if (!clk->clksel || !clk->clksel_mask) + return; - for (clkr = clks->rates; clkr->div; clkr++) { - if ((clkr->flags & cpu_mask) && (clkr->val == field_val)) - break; - } + r = __raw_readl(clk->clksel_reg) & clk->clksel_mask; + r >>= __ffs(clk->clksel_mask); - if (!clkr->div) { - printk(KERN_ERR "clock: Could not find fieldval %d for " - "clock %s parent %s\n", field_val, clk->name, - clk->parent->name); - return 0; + for (clks = clk->clksel; clks->parent && !found; clks++) { + for (clkr = clks->rates; clkr->div && !found; clkr++) { + if (!(clkr->flags & cpu_mask)) + continue; + + if (clkr->val == r) { + if (clk->parent != clks->parent) { + pr_debug("clock: inited %s parent " + "to %s (was %s)\n", + clk->name, clks->parent->name, + ((clk->parent) ? + clk->parent->name : "NULL")); + clk_reparent(clk, clks->parent); + }; + found = 1; + } + } } - return clkr->div; + /* This indicates a data error */ + WARN(!found, "clock: %s: init parent: could not find regval %0x\n", + clk->name, r); + + return; } /** - * omap2_divisor_to_clksel() - turn clksel integer divisor into a field value - * @clk: OMAP struct clk to use - * @div: integer divisor to search for + * omap2_clksel_recalc() - function ptr to pass via struct clk .recalc field + * @clk: struct clk * * - * Given a struct clk of a rate-selectable clksel clock, and a clock divisor, - * find the corresponding register field value. The return register value is - * the value before left-shifting. Returns ~0 on error + * This function is intended to be called only by the clock framework. + * Each clksel clock should have its struct clk .recalc field set to this + * function. Returns the clock's current rate, based on its parent's rate + * and its current divisor setting in the hardware. */ -u32 omap2_divisor_to_clksel(struct clk *clk, u32 div) +unsigned long omap2_clksel_recalc(struct clk *clk) { - const struct clksel *clks; - const struct clksel_rate *clkr; + unsigned long rate; + u32 div = 0; - /* should never happen */ - WARN_ON(div == 0); + div = _read_divisor(clk); + if (div == 0) + return clk->rate; - clks = _omap2_get_clksel_by_parent(clk, clk->parent); - if (!clks) - return ~0; + rate = clk->parent->rate / div; - for (clkr = clks->rates; clkr->div; clkr++) { - if ((clkr->flags & cpu_mask) && (clkr->div == div)) - break; - } + pr_debug("clock: %s: recalc'd rate is %ld (div %d)\n", clk->name, + rate, div); - if (!clkr->div) { - printk(KERN_ERR "clock: Could not find divisor %d for " - "clock %s parent %s\n", div, clk->name, - clk->parent->name); - return ~0; - } - - return clkr->val; + return rate; } /** - * omap2_clksel_get_divisor - get current divider applied to parent clock. - * @clk: OMAP struct clk to use. + * omap2_clksel_round_rate() - find rounded rate for the given clock and rate + * @clk: OMAP struct clk to use + * @target_rate: desired clock rate + * + * This function is intended to be called only by the clock framework. + * Finds best target rate based on the source clock and possible dividers. + * rates. The divider array must be sorted with smallest divider first. * - * Returns the integer divisor upon success or 0 on error. + * Returns the rounded clock rate or returns 0xffffffff on error. */ -u32 omap2_clksel_get_divisor(struct clk *clk) +long omap2_clksel_round_rate(struct clk *clk, unsigned long target_rate) { - u32 v; - - if (!clk->clksel_mask) - return 0; - - v = __raw_readl(clk->clksel_reg) & clk->clksel_mask; - v >>= __ffs(clk->clksel_mask); + u32 new_div; - return omap2_clksel_to_divisor(clk, v); + return omap2_clksel_round_rate_div(clk, target_rate, &new_div); } +/** + * omap2_clksel_set_rate() - program clock rate in hardware + * @clk: struct clk * to program rate + * @rate: target rate to program + * + * This function is intended to be called only by the clock framework. + * Program @clk's rate to @rate in the hardware. The clock can be + * either enabled or disabled when this happens, although if the clock + * is enabled, some downstream devices may glitch or behave + * unpredictably when the clock rate is changed - this depends on the + * hardware. This function does not currently check the usecount of + * the clock, so if multiple drivers are using the clock, and the rate + * is changed, they will all be affected without any notification. + * Returns -EINVAL upon error, or 0 upon success. + */ int omap2_clksel_set_rate(struct clk *clk, unsigned long rate) { - u32 v, field_val, validrate, new_div = 0; + u32 field_val, validrate, new_div = 0; - if (!clk->clksel_mask) + if (!clk->clksel || !clk->clksel_mask) return -EINVAL; validrate = omap2_clksel_round_rate_div(clk, rate, &new_div); if (validrate != rate) return -EINVAL; - field_val = omap2_divisor_to_clksel(clk, new_div); + field_val = _divisor_to_clksel(clk, new_div); if (field_val == ~0) return -EINVAL; - v = __raw_readl(clk->clksel_reg); - v &= ~clk->clksel_mask; - v |= field_val << __ffs(clk->clksel_mask); - __raw_writel(v, clk->clksel_reg); - v = __raw_readl(clk->clksel_reg); /* OCP barrier */ + _write_clksel_reg(clk, field_val); clk->rate = clk->parent->rate / new_div; + pr_debug("clock: %s: set rate to %ld\n", clk->name, clk->rate); + return 0; } +/* + * Clksel parent setting function - not passed in struct clk function + * pointer - instead, the OMAP clock code currently assumes that any + * parent-setting clock is a clksel clock, and calls + * omap2_clksel_set_parent() by default + */ + +/** + * omap2_clksel_set_parent() - change a clock's parent clock + * @clk: struct clk * of the child clock + * @new_parent: struct clk * of the new parent clock + * + * This function is intended to be called only by the clock framework. + * Change the parent clock of clock @clk to @new_parent. This is + * intended to be used while @clk is disabled. This function does not + * currently check the usecount of the clock, so if multiple drivers + * are using the clock, and the parent is changed, they will all be + * affected without any notification. Returns -EINVAL upon error, or + * 0 upon success. + */ int omap2_clksel_set_parent(struct clk *clk, struct clk *new_parent) { - u32 field_val, v, parent_div; + u32 field_val = 0; + u32 parent_div; if (!clk->clksel || !clk->clksel_mask) return -EINVAL; - parent_div = _omap2_clksel_get_src_field(new_parent, clk, &field_val); + parent_div = _get_div_and_fieldval(new_parent, clk, &field_val); if (!parent_div) return -EINVAL; - /* Set new source value (previous dividers if any in effect) */ - v = __raw_readl(clk->clksel_reg); - v &= ~clk->clksel_mask; - v |= field_val << __ffs(clk->clksel_mask); - __raw_writel(v, clk->clksel_reg); - v = __raw_readl(clk->clksel_reg); /* OCP barrier */ + _write_clksel_reg(clk, field_val); clk_reparent(clk, new_parent); @@ -423,7 +502,7 @@ int omap2_clksel_set_parent(struct clk *clk, struct clk *new_parent) if (parent_div > 0) clk->rate /= parent_div; - pr_debug("clock: set parent of %s to %s (new rate %ld)\n", + pr_debug("clock: %s: set parent to %s (new rate %ld)\n", clk->name, clk->parent->name, clk->rate); return 0; diff --git a/arch/arm/mach-omap2/clock.c b/arch/arm/mach-omap2/clock.c index a6d0b34b7990..605f531783a8 100644 --- a/arch/arm/mach-omap2/clock.c +++ b/arch/arm/mach-omap2/clock.c @@ -334,6 +334,15 @@ oce_err1: return ret; } +/* Given a clock and a rate apply a clock specific rounding function */ +long omap2_clk_round_rate(struct clk *clk, unsigned long rate) +{ + if (clk->round_rate) + return clk->round_rate(clk, rate); + + return clk->rate; +} + /* Set the clock rate for a clock source */ int omap2_clk_set_rate(struct clk *clk, unsigned long rate) { diff --git a/arch/arm/mach-omap2/clock.h b/arch/arm/mach-omap2/clock.h index ad8a1f7c1afc..a535c7a2a62a 100644 --- a/arch/arm/mach-omap2/clock.h +++ b/arch/arm/mach-omap2/clock.h @@ -73,19 +73,20 @@ void omap2_clk_disable_unused(struct clk *clk); #define omap2_clk_disable_unused NULL #endif -unsigned long omap2_clksel_recalc(struct clk *clk); void omap2_init_clk_clkdm(struct clk *clk); -void omap2_init_clksel_parent(struct clk *clk); -u32 omap2_clksel_get_divisor(struct clk *clk); + +/* clkt_clksel.c public functions */ u32 omap2_clksel_round_rate_div(struct clk *clk, unsigned long target_rate, u32 *new_div); -u32 omap2_clksel_to_divisor(struct clk *clk, u32 field_val); -u32 omap2_divisor_to_clksel(struct clk *clk, u32 div); +void omap2_init_clksel_parent(struct clk *clk); +unsigned long omap2_clksel_recalc(struct clk *clk); long omap2_clksel_round_rate(struct clk *clk, unsigned long target_rate); int omap2_clksel_set_rate(struct clk *clk, unsigned long rate); int omap2_clksel_set_parent(struct clk *clk, struct clk *new_parent); + u32 omap2_get_dpll_rate(struct clk *clk); void omap2_init_dpll_parent(struct clk *clk); + int omap2_wait_clock_ready(void __iomem *reg, u32 cval, const char *name); |