--- /dev/null
+/*
+ * 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.
+ *
+ *
+ * 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
+ * mechanism.
+ */
+#undef DEBUG
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/clk-provider.h>
+#include <linux/io.h>
+#include <linux/bug.h>
+
+#include "clock.h"
+
+/* Private functions */
+
+/**
+ * _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 *_get_clksel_by_parent(struct clk_hw_omap *clk,
+ struct clk *src_clk)
+{
+ const struct clksel *clks;
+
+ if (!src_clk)
+ return NULL;
+
+ for (clks = clk->clksel; clks->parent; clks++)
+ if (clks->parent == src_clk)
+ break; /* Found the requested parent */
+
+ if (!clks->parent) {
+ /* This indicates a data problem */
+ WARN(1, "clock: %s: could not find parent clock %s in clksel array\n",
+ __clk_get_name(clk->hw.clk), __clk_get_name(src_clk));
+ return NULL;
+ }
+
+ return clks;
+}
+
+/**
+ * _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_hw_omap *clk, u32 field_val)
+{
+ u32 v;
+
+ v = omap2_clk_readl(clk, clk->clksel_reg);
+ v &= ~clk->clksel_mask;
+ v |= field_val << __ffs(clk->clksel_mask);
+ omap2_clk_writel(v, clk, clk->clksel_reg);
+
+ v = omap2_clk_readl(clk, clk->clksel_reg); /* OCP barrier */
+}
+
+/**
+ * _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 or returns the actual integer divisor
+ * upon success.
+ */
+static u32 _clksel_to_divisor(struct clk_hw_omap *clk, u32 field_val)
+{
+ const struct clksel *clks;
+ const struct clksel_rate *clkr;
+ struct clk *parent;
+
+ parent = __clk_get_parent(clk->hw.clk);
+
+ clks = _get_clksel_by_parent(clk, parent);
+ if (!clks)
+ return 0;
+
+ for (clkr = clks->rates; clkr->div; clkr++) {
+ if (!(clkr->flags & cpu_mask))
+ continue;
+
+ if (clkr->val == field_val)
+ break;
+ }
+
+ if (!clkr->div) {
+ /* This indicates a data error */
+ WARN(1, "clock: %s: could not find fieldval %d for parent %s\n",
+ __clk_get_name(clk->hw.clk), field_val,
+ __clk_get_name(parent));
+ return 0;
+ }
+
+ return clkr->div;
+}
+
+/**
+ * _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.
+ */
+static u32 _divisor_to_clksel(struct clk_hw_omap *clk, u32 div)
+{
+ const struct clksel *clks;
+ const struct clksel_rate *clkr;
+ struct clk *parent;
+
+ /* should never happen */
+ WARN_ON(div == 0);
+
+ parent = __clk_get_parent(clk->hw.clk);
+ clks = _get_clksel_by_parent(clk, parent);
+ if (!clks)
+ return ~0;
+
+ for (clkr = clks->rates; clkr->div; clkr++) {
+ if (!(clkr->flags & cpu_mask))
+ continue;
+
+ if (clkr->div == div)
+ break;
+ }
+
+ if (!clkr->div) {
+ pr_err("clock: %s: could not find divisor %d for parent %s\n",
+ __clk_get_name(clk->hw.clk), div,
+ __clk_get_name(parent));
+ 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_hw_omap *clk)
+{
+ u32 v;
+
+ if (!clk->clksel || !clk->clksel_mask)
+ return 0;
+
+ v = omap2_clk_readl(clk, 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.
+ */
+u32 omap2_clksel_round_rate_div(struct clk_hw_omap *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;
+ struct clk *parent;
+ unsigned long parent_rate;
+ const char *clk_name;
+
+ parent = __clk_get_parent(clk->hw.clk);
+ clk_name = __clk_get_name(clk->hw.clk);
+ parent_rate = __clk_get_rate(parent);
+
+ 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 = _get_clksel_by_parent(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: %s: clksel_rate table not sorted\n",
+ clk_name);
+
+ last_div = clkr->div;
+
+ test_rate = parent_rate / clkr->div;
+
+ if (test_rate <= target_rate)
+ break; /* found it */
+ }
+
+ if (!clkr->div) {
+ pr_err("clock: %s: could not find divisor for target rate %ld for parent %s\n",
+ clk_name, target_rate, __clk_get_name(parent));
+ return ~0;
+ }
+
+ *new_div = clkr->div;
+
+ pr_debug("clock: new_div = %d, new_rate = %ld\n", *new_div,
+ (parent_rate / clkr->div));
+
+ return parent_rate / clkr->div;
+}
+
+/*
+ * Clocktype interface functions to the OMAP clock code
+ * (i.e., those used in struct clk field function pointers, etc.)
+ */
+
+/**
+ * omap2_clksel_find_parent_index() - return the array index of the current
+ * hardware parent of @hw
+ * @hw: struct clk_hw * to find the current hardware parent of
+ *
+ * Given a struct clk_hw pointer @hw to the 'hw' member of a struct
+ * clk_hw_omap record representing a source-selectable hardware clock,
+ * read the hardware register and determine what its parent is
+ * currently set to. Intended to be called only by the common clock
+ * framework struct clk_hw_ops.get_parent function pointer. Return
+ * the array index of this parent clock upon success -- there is no
+ * way to return an error, so if we encounter an error, just WARN()
+ * and pretend that we know that we're doing.
+ */
+u8 omap2_clksel_find_parent_index(struct clk_hw *hw)
+{
+ struct clk_hw_omap *clk = to_clk_hw_omap(hw);
+ const struct clksel *clks;
+ const struct clksel_rate *clkr;
+ u32 r, found = 0;
+ struct clk *parent;
+ const char *clk_name;
+ int ret = 0, f = 0;
+
+ parent = __clk_get_parent(hw->clk);
+ clk_name = __clk_get_name(hw->clk);
+
+ /* XXX should be able to return an error */
+ WARN((!clk->clksel || !clk->clksel_mask),
+ "clock: %s: attempt to call on a non-clksel clock", clk_name);
+
+ r = omap2_clk_readl(clk, 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))
+ continue;
+
+ if (clkr->val == r) {
+ found = 1;
+ ret = f;
+ }
+ }
+ f++;
+ }
+
+ /* This indicates a data error */
+ WARN(!found, "clock: %s: init parent: could not find regval %0x\n",
+ clk_name, r);
+
+ return ret;
+}
+
+
+/**
+ * omap2_clksel_recalc() - function ptr to pass via struct clk .recalc field
+ * @clk: struct clk *
+ *
+ * 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.
+ */
+unsigned long omap2_clksel_recalc(struct clk_hw *hw, unsigned long parent_rate)
+{
+ unsigned long rate;
+ u32 div = 0;
+ struct clk_hw_omap *clk = to_clk_hw_omap(hw);
+
+ if (!parent_rate)
+ return 0;
+
+ div = _read_divisor(clk);
+ if (!div)
+ rate = parent_rate;
+ else
+ rate = parent_rate / div;
+
+ pr_debug("%s: recalc'd %s's rate to %lu (div %d)\n", __func__,
+ __clk_get_name(hw->clk), rate, div);
+
+ return rate;
+}
+
+/**
+ * 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 rounded clock rate or returns 0xffffffff on error.
+ */
+long omap2_clksel_round_rate(struct clk_hw *hw, unsigned long target_rate,
+ unsigned long *parent_rate)
+{
+ struct clk_hw_omap *clk = to_clk_hw_omap(hw);
+ u32 new_div;
+
+ 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_hw *hw, unsigned long rate,
+ unsigned long parent_rate)
+{
+ struct clk_hw_omap *clk = to_clk_hw_omap(hw);
+ u32 field_val, validrate, new_div = 0;
+
+ 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 = _divisor_to_clksel(clk, new_div);
+ if (field_val == ~0)
+ return -EINVAL;
+
+ _write_clksel_reg(clk, field_val);
+
+ pr_debug("clock: %s: set rate to %ld\n", __clk_get_name(hw->clk),
+ __clk_get_rate(hw->clk));
+
+ 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_hw *hw, u8 field_val)
+{
+ struct clk_hw_omap *clk = to_clk_hw_omap(hw);
+
+ if (!clk->clksel || !clk->clksel_mask)
+ return -EINVAL;
+
+ _write_clksel_reg(clk, field_val);
+ return 0;
+}
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