* 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
#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
*
* 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;
}
return clks;
}
-/*
- * Converts encoded control register address into a full address
- * On error, the return value (parent_div) will be 0.
+/**
+ * _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
+ *
+ * Given an intended new parent struct clk * @src_clk, and the struct
+ * clk * @clk to the clock that is being reparented, find the
+ * appropriate rate divisor for the new clock (returned as the return
+ * value), and the corresponding register bitfield data to program to
+ * reach that divisor (returned in the u32 pointed to by @field_val).
+ * Returns 0 on error, or returns the newly-selected divisor upon
+ * success (in this latter case, the corresponding register bitfield
+ * value is passed back in the variable pointed to by @field_val)
*/
-static u32 _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;
+ 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;
+ /*
+ * Find the highest divisor (e.g., the one resulting in the
+ * lowest rate) to use as the default. This should avoid
+ * clock rates that are too high for the device. XXX A better
+ * solution here would be to try to determine if there is a
+ * divisor matching the original clock rate before the parent
+ * switch, and if it cannot be found, to fall back to the
+ * highest divisor.
+ */
for (clkr = clks->rates; clkr->div; clkr++) {
- if (clkr->flags & cpu_mask && clkr->flags & DEFAULT_RATE)
- break; /* Found the default rate for this platform */
+ if (!(clkr->flags & cpu_mask))
+ continue;
+
+ if (clkr->div > max_div) {
+ max_div = clkr->div;
+ max_clkr = clkr;
+ }
}
- if (!clkr->div) {
- printk(KERN_ERR "clock: Could not find default rate for "
- "clock %s parent %s\n", clk->name,
- src_clk->parent->name);
+ if (max_div == 0) {
+ /* 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;
}
- /* Should never happen. Add a clksel mask to the struct clk. */
- WARN_ON(clk->clksel_mask == 0);
+ *field_val = max_clkr->val;
- *field_val = clkr->val;
-
- return clkr->div;
+ 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;
+}
+
+/**
+ * _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
+ * 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.
- * Note that this will not work for clocks which are part of CONFIG_PARTICIPANT,
- * they are only settable as part of virtual_prcm set.
+ * This function is also used by the DPLL3 M2 divider code.
*
* Returns the rounded clock rate or returns 0xffffffff on error.
*/
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;
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;
-
- /* should never happen */
- WARN_ON(div == 0);
+ unsigned long rate;
+ u32 div = 0;
- clks = _omap2_get_clksel_by_parent(clk, clk->parent);
- if (!clks)
- return ~0;
+ div = _read_divisor(clk);
+ if (div == 0)
+ return clk->rate;
- for (clkr = clks->rates; clkr->div; clkr++) {
- if ((clkr->flags & cpu_mask) && (clkr->div == div))
- break;
- }
+ rate = clk->parent->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;
- }
+ pr_debug("clock: %s: recalc'd rate is %ld (div %d)\n", clk->name,
+ rate, div);
- 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)
+ 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);
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;
git.openpandora.org / pandora-kernel.git / blobdiff