Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6

1 files changed, 286 insertions, 186 deletions

diff --git a/arch/arm/mach-omap2/clkt_clksel.c b/arch/arm/mach-omap2/clkt_clksel.c
index e50812dd03fd..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
  *
@@ -44,141 +59,217 @@
  * 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.
  */
@@ -190,12 +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;
 
@@ -231,168 +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;
-
-        /* 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);
 
@@ -402,7 +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;