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-rw-r--r--arch/arm/mach-omap2/clkt_clksel.c409
1 files changed, 409 insertions, 0 deletions
diff --git a/arch/arm/mach-omap2/clkt_clksel.c b/arch/arm/mach-omap2/clkt_clksel.c
new file mode 100644
index 00000000000..e50812dd03f
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+++ b/arch/arm/mach-omap2/clkt_clksel.c
@@ -0,0 +1,409 @@
+/*
+ * clkt_clksel.c - OMAP2/3/4 clksel clock functions
+ *
+ * Copyright (C) 2005-2008 Texas Instruments, Inc.
+ * Copyright (C) 2004-2010 Nokia Corporation
+ *
+ * Contacts:
+ * Richard Woodruff <r-woodruff2@ti.com>
+ * Paul Walmsley
+ *
+ * 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.
+ *
+ * XXX At some point these clksel clocks should be split into
+ * "divider" clocks and "mux" clocks to better match the hardware.
+ *
+ * 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
+ * mechanism.
+ */
+#undef DEBUG
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+
+#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
+ * @clk: OMAP struct clk ptr to inspect
+ * @src_clk: OMAP struct clk ptr of the parent clk to search for
+ *
+ * Scan the struct clksel array associated with the clock to find
+ * 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)
+{
+ const struct clksel *clks;
+
+ if (!clk->clksel)
+ return NULL;
+
+ 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);
+ return NULL;
+ }
+
+ return clks;
+}
+
+/*
+ * Converts encoded control register address into a full address
+ * On error, the return value (parent_div) will be 0.
+ */
+static u32 _omap2_clksel_get_src_field(struct clk *src_clk, struct clk *clk,
+ u32 *field_val)
+{
+ const struct clksel *clks;
+ const struct clksel_rate *clkr;
+
+ clks = _omap2_get_clksel_by_parent(clk, src_clk);
+ if (!clks)
+ return 0;
+
+ 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->div) {
+ printk(KERN_ERR "clock: Could not find default rate 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 = clkr->val;
+
+ return clkr->div;
+}
+
+
+/* Public functions */
+
+/**
+ * omap2_init_clksel_parent - set a clksel clk's parent field from the hardware
+ * @clk: OMAP clock struct ptr to use
+ *
+ * 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.
+ */
+void omap2_init_clksel_parent(struct clk *clk)
+{
+ const struct clksel *clks;
+ const struct clksel_rate *clkr;
+ u32 r, found = 0;
+
+ if (!clk->clksel)
+ return;
+
+ r = __raw_readl(clk->clksel_reg) & clk->clksel_mask;
+ r >>= __ffs(clk->clksel_mask);
+
+ 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 (!found)
+ printk(KERN_ERR "clock: init parent: could not find "
+ "regval %0x for clock %s\n", r, clk->name);
+
+ return;
+}
+
+/*
+ * Used for clocks that are part of CLKSEL_xyz governed clocks.
+ * REVISIT: Maybe change to use clk->enable() functions like on omap1?
+ */
+unsigned long omap2_clksel_recalc(struct clk *clk)
+{
+ unsigned long rate;
+ u32 div = 0;
+
+ pr_debug("clock: recalc'ing clksel clk %s\n", clk->name);
+
+ div = omap2_clksel_get_divisor(clk);
+ if (div == 0)
+ return clk->rate;
+
+ rate = clk->parent->rate / div;
+
+ pr_debug("clock: new clock rate is %ld (div %d)\n", rate, div);
+
+ return 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.
+ *
+ * Returns the rounded clock rate or returns 0xffffffff on error.
+ */
+u32 omap2_clksel_round_rate_div(struct clk *clk, unsigned long target_rate,
+ u32 *new_div)
+{
+ unsigned long test_rate;
+ const struct clksel *clks;
+ const struct clksel_rate *clkr;
+ u32 last_div = 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);
+ if (!clks)
+ return ~0;
+
+ for (clkr = clks->rates; clkr->div; clkr++) {
+ if (!(clkr->flags & cpu_mask))
+ continue;
+
+ /* Sanity check */
+ if (clkr->div <= last_div)
+ pr_err("clock: clksel_rate table not sorted "
+ "for clock %s", clk->name);
+
+ last_div = clkr->div;
+
+ test_rate = clk->parent->rate / clkr->div;
+
+ if (test_rate <= target_rate)
+ break; /* found it */
+ }
+
+ if (!clkr->div) {
+ pr_err("clock: Could not find divisor for target "
+ "rate %ld for clock %s parent %s\n", target_rate,
+ clk->name, clk->parent->name);
+ return ~0;
+ }
+
+ *new_div = clkr->div;
+
+ pr_debug("clock: new_div = %d, new_rate = %ld\n", *new_div,
+ (clk->parent->rate / clkr->div));
+
+ 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.
+ */
+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
+ *
+ * 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
+ */
+u32 omap2_clksel_to_divisor(struct clk *clk, u32 field_val)
+{
+ const struct clksel *clks;
+ const struct clksel_rate *clkr;
+
+ clks = _omap2_get_clksel_by_parent(clk, clk->parent);
+ if (!clks)
+ return 0;
+
+ for (clkr = clks->rates; clkr->div; clkr++) {
+ if ((clkr->flags & cpu_mask) && (clkr->val == field_val))
+ break;
+ }
+
+ 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;
+ }
+
+ return clkr->div;
+}
+
+/**
+ * omap2_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. The return register value is
+ * the value before left-shifting. Returns ~0 on error
+ */
+u32 omap2_divisor_to_clksel(struct clk *clk, u32 div)
+{
+ const struct clksel *clks;
+ const struct clksel_rate *clkr;
+
+ /* should never happen */
+ WARN_ON(div == 0);
+
+ clks = _omap2_get_clksel_by_parent(clk, clk->parent);
+ if (!clks)
+ return ~0;
+
+ for (clkr = clks->rates; clkr->div; clkr++) {
+ if ((clkr->flags & cpu_mask) && (clkr->div == div))
+ break;
+ }
+
+ 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;
+}
+
+/**
+ * omap2_clksel_get_divisor - get current divider applied to parent clock.
+ * @clk: OMAP struct clk to use.
+ *
+ * Returns the integer divisor upon success or 0 on error.
+ */
+u32 omap2_clksel_get_divisor(struct clk *clk)
+{
+ u32 v;
+
+ if (!clk->clksel_mask)
+ return 0;
+
+ v = __raw_readl(clk->clksel_reg) & clk->clksel_mask;
+ v >>= __ffs(clk->clksel_mask);
+
+ return omap2_clksel_to_divisor(clk, v);
+}
+
+int omap2_clksel_set_rate(struct clk *clk, unsigned long rate)
+{
+ u32 v, field_val, validrate, new_div = 0;
+
+ if (!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);
+ 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 */
+
+ clk->rate = clk->parent->rate / new_div;
+
+ return 0;
+}
+
+int omap2_clksel_set_parent(struct clk *clk, struct clk *new_parent)
+{
+ u32 field_val, v, parent_div;
+
+ if (!clk->clksel)
+ return -EINVAL;
+
+ parent_div = _omap2_clksel_get_src_field(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 */
+
+ clk_reparent(clk, new_parent);
+
+ /* CLKSEL clocks follow their parents' rates, divided by a divisor */
+ clk->rate = new_parent->rate;
+
+ if (parent_div > 0)
+ clk->rate /= parent_div;
+
+ pr_debug("clock: set parent of %s to %s (new rate %ld)\n",
+ clk->name, clk->parent->name, clk->rate);
+
+ return 0;
+}