From 81ec98898188639ac53413605681b3e3bb0a2ff1 Mon Sep 17 00:00:00 2001 From: Mark Salter Date: Tue, 4 Oct 2011 11:10:50 -0400 Subject: C6X: clocks The C6X SoCs contain several PLL controllers each with up to 16 clock outputs feeding into the cores or peripheral clock domains. The hardware is very similar to arm/mach-davinci clocks. This is still a work in progress which needs to be updated once device tree clock binding changes shake out. Signed-off-by: Mark Salter Signed-off-by: Aurelien Jacquiot Acked-by: Arnd Bergmann --- arch/c6x/platforms/pll.c | 444 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 444 insertions(+) create mode 100644 arch/c6x/platforms/pll.c (limited to 'arch/c6x/platforms/pll.c') diff --git a/arch/c6x/platforms/pll.c b/arch/c6x/platforms/pll.c new file mode 100644 index 000000000000..3aa898f7ce4d --- /dev/null +++ b/arch/c6x/platforms/pll.c @@ -0,0 +1,444 @@ +/* + * Clock and PLL control for C64x+ devices + * + * Copyright (C) 2010, 2011 Texas Instruments. + * Contributed by: Mark Salter + * + * Copied heavily from arm/mach-davinci/clock.c, so: + * + * Copyright (C) 2006-2007 Texas Instruments. + * Copyright (C) 2008-2009 Deep Root Systems, LLC + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + */ + +#include +#include +#include +#include +#include + +#include +#include + +static LIST_HEAD(clocks); +static DEFINE_MUTEX(clocks_mutex); +static DEFINE_SPINLOCK(clockfw_lock); + +static void __clk_enable(struct clk *clk) +{ + if (clk->parent) + __clk_enable(clk->parent); + clk->usecount++; +} + +static void __clk_disable(struct clk *clk) +{ + if (WARN_ON(clk->usecount == 0)) + return; + --clk->usecount; + + if (clk->parent) + __clk_disable(clk->parent); +} + +int clk_enable(struct clk *clk) +{ + unsigned long flags; + + if (clk == NULL || IS_ERR(clk)) + return -EINVAL; + + spin_lock_irqsave(&clockfw_lock, flags); + __clk_enable(clk); + spin_unlock_irqrestore(&clockfw_lock, flags); + + return 0; +} +EXPORT_SYMBOL(clk_enable); + +void clk_disable(struct clk *clk) +{ + unsigned long flags; + + if (clk == NULL || IS_ERR(clk)) + return; + + spin_lock_irqsave(&clockfw_lock, flags); + __clk_disable(clk); + spin_unlock_irqrestore(&clockfw_lock, flags); +} +EXPORT_SYMBOL(clk_disable); + +unsigned long clk_get_rate(struct clk *clk) +{ + if (clk == NULL || IS_ERR(clk)) + return -EINVAL; + + return clk->rate; +} +EXPORT_SYMBOL(clk_get_rate); + +long clk_round_rate(struct clk *clk, unsigned long rate) +{ + if (clk == NULL || IS_ERR(clk)) + return -EINVAL; + + if (clk->round_rate) + return clk->round_rate(clk, rate); + + return clk->rate; +} +EXPORT_SYMBOL(clk_round_rate); + +/* Propagate rate to children */ +static void propagate_rate(struct clk *root) +{ + struct clk *clk; + + list_for_each_entry(clk, &root->children, childnode) { + if (clk->recalc) + clk->rate = clk->recalc(clk); + propagate_rate(clk); + } +} + +int clk_set_rate(struct clk *clk, unsigned long rate) +{ + unsigned long flags; + int ret = -EINVAL; + + if (clk == NULL || IS_ERR(clk)) + return ret; + + if (clk->set_rate) + ret = clk->set_rate(clk, rate); + + spin_lock_irqsave(&clockfw_lock, flags); + if (ret == 0) { + if (clk->recalc) + clk->rate = clk->recalc(clk); + propagate_rate(clk); + } + spin_unlock_irqrestore(&clockfw_lock, flags); + + return ret; +} +EXPORT_SYMBOL(clk_set_rate); + +int clk_set_parent(struct clk *clk, struct clk *parent) +{ + unsigned long flags; + + if (clk == NULL || IS_ERR(clk)) + return -EINVAL; + + /* Cannot change parent on enabled clock */ + if (WARN_ON(clk->usecount)) + return -EINVAL; + + mutex_lock(&clocks_mutex); + clk->parent = parent; + list_del_init(&clk->childnode); + list_add(&clk->childnode, &clk->parent->children); + mutex_unlock(&clocks_mutex); + + spin_lock_irqsave(&clockfw_lock, flags); + if (clk->recalc) + clk->rate = clk->recalc(clk); + propagate_rate(clk); + spin_unlock_irqrestore(&clockfw_lock, flags); + + return 0; +} +EXPORT_SYMBOL(clk_set_parent); + +int clk_register(struct clk *clk) +{ + if (clk == NULL || IS_ERR(clk)) + return -EINVAL; + + if (WARN(clk->parent && !clk->parent->rate, + "CLK: %s parent %s has no rate!\n", + clk->name, clk->parent->name)) + return -EINVAL; + + mutex_lock(&clocks_mutex); + list_add_tail(&clk->node, &clocks); + if (clk->parent) + list_add_tail(&clk->childnode, &clk->parent->children); + mutex_unlock(&clocks_mutex); + + /* If rate is already set, use it */ + if (clk->rate) + return 0; + + /* Else, see if there is a way to calculate it */ + if (clk->recalc) + clk->rate = clk->recalc(clk); + + /* Otherwise, default to parent rate */ + else if (clk->parent) + clk->rate = clk->parent->rate; + + return 0; +} +EXPORT_SYMBOL(clk_register); + +void clk_unregister(struct clk *clk) +{ + if (clk == NULL || IS_ERR(clk)) + return; + + mutex_lock(&clocks_mutex); + list_del(&clk->node); + list_del(&clk->childnode); + mutex_unlock(&clocks_mutex); +} +EXPORT_SYMBOL(clk_unregister); + + +static u32 pll_read(struct pll_data *pll, int reg) +{ + return soc_readl(pll->base + reg); +} + +static unsigned long clk_sysclk_recalc(struct clk *clk) +{ + u32 v, plldiv = 0; + struct pll_data *pll; + unsigned long rate = clk->rate; + + if (WARN_ON(!clk->parent)) + return rate; + + rate = clk->parent->rate; + + /* the parent must be a PLL */ + if (WARN_ON(!clk->parent->pll_data)) + return rate; + + pll = clk->parent->pll_data; + + /* If pre-PLL, source clock is before the multiplier and divider(s) */ + if (clk->flags & PRE_PLL) + rate = pll->input_rate; + + if (!clk->div) { + pr_debug("%s: (no divider) rate = %lu KHz\n", + clk->name, rate / 1000); + return rate; + } + + if (clk->flags & FIXED_DIV_PLL) { + rate /= clk->div; + pr_debug("%s: (fixed divide by %d) rate = %lu KHz\n", + clk->name, clk->div, rate / 1000); + return rate; + } + + v = pll_read(pll, clk->div); + if (v & PLLDIV_EN) + plldiv = (v & PLLDIV_RATIO_MASK) + 1; + + if (plldiv == 0) + plldiv = 1; + + rate /= plldiv; + + pr_debug("%s: (divide by %d) rate = %lu KHz\n", + clk->name, plldiv, rate / 1000); + + return rate; +} + +static unsigned long clk_leafclk_recalc(struct clk *clk) +{ + if (WARN_ON(!clk->parent)) + return clk->rate; + + pr_debug("%s: (parent %s) rate = %lu KHz\n", + clk->name, clk->parent->name, clk->parent->rate / 1000); + + return clk->parent->rate; +} + +static unsigned long clk_pllclk_recalc(struct clk *clk) +{ + u32 ctrl, mult = 0, prediv = 0, postdiv = 0; + u8 bypass; + struct pll_data *pll = clk->pll_data; + unsigned long rate = clk->rate; + + if (clk->flags & FIXED_RATE_PLL) + return rate; + + ctrl = pll_read(pll, PLLCTL); + rate = pll->input_rate = clk->parent->rate; + + if (ctrl & PLLCTL_PLLEN) + bypass = 0; + else + bypass = 1; + + if (pll->flags & PLL_HAS_MUL) { + mult = pll_read(pll, PLLM); + mult = (mult & PLLM_PLLM_MASK) + 1; + } + if (pll->flags & PLL_HAS_PRE) { + prediv = pll_read(pll, PLLPRE); + if (prediv & PLLDIV_EN) + prediv = (prediv & PLLDIV_RATIO_MASK) + 1; + else + prediv = 0; + } + if (pll->flags & PLL_HAS_POST) { + postdiv = pll_read(pll, PLLPOST); + if (postdiv & PLLDIV_EN) + postdiv = (postdiv & PLLDIV_RATIO_MASK) + 1; + else + postdiv = 1; + } + + if (!bypass) { + if (prediv) + rate /= prediv; + if (mult) + rate *= mult; + if (postdiv) + rate /= postdiv; + + pr_debug("PLL%d: input = %luMHz, pre[%d] mul[%d] post[%d] " + "--> %luMHz output.\n", + pll->num, clk->parent->rate / 1000000, + prediv, mult, postdiv, rate / 1000000); + } else + pr_debug("PLL%d: input = %luMHz, bypass mode.\n", + pll->num, clk->parent->rate / 1000000); + + return rate; +} + + +static void __init __init_clk(struct clk *clk) +{ + INIT_LIST_HEAD(&clk->node); + INIT_LIST_HEAD(&clk->children); + INIT_LIST_HEAD(&clk->childnode); + + if (!clk->recalc) { + + /* Check if clock is a PLL */ + if (clk->pll_data) + clk->recalc = clk_pllclk_recalc; + + /* Else, if it is a PLL-derived clock */ + else if (clk->flags & CLK_PLL) + clk->recalc = clk_sysclk_recalc; + + /* Otherwise, it is a leaf clock (PSC clock) */ + else if (clk->parent) + clk->recalc = clk_leafclk_recalc; + } +} + +void __init c6x_clks_init(struct clk_lookup *clocks) +{ + struct clk_lookup *c; + struct clk *clk; + size_t num_clocks = 0; + + for (c = clocks; c->clk; c++) { + clk = c->clk; + + __init_clk(clk); + clk_register(clk); + num_clocks++; + + /* Turn on clocks that Linux doesn't otherwise manage */ + if (clk->flags & ALWAYS_ENABLED) + clk_enable(clk); + } + + clkdev_add_table(clocks, num_clocks); +} + +#ifdef CONFIG_DEBUG_FS + +#include +#include + +#define CLKNAME_MAX 10 /* longest clock name */ +#define NEST_DELTA 2 +#define NEST_MAX 4 + +static void +dump_clock(struct seq_file *s, unsigned nest, struct clk *parent) +{ + char *state; + char buf[CLKNAME_MAX + NEST_DELTA * NEST_MAX]; + struct clk *clk; + unsigned i; + + if (parent->flags & CLK_PLL) + state = "pll"; + else + state = ""; + + /* name */ + memset(buf, ' ', sizeof(buf) - 1); + buf[sizeof(buf) - 1] = 0; + i = strlen(parent->name); + memcpy(buf + nest, parent->name, + min(i, (unsigned)(sizeof(buf) - 1 - nest))); + + seq_printf(s, "%s users=%2d %-3s %9ld Hz\n", + buf, parent->usecount, state, clk_get_rate(parent)); + /* REVISIT show device associations too */ + + /* cost is now small, but not linear... */ + list_for_each_entry(clk, &parent->children, childnode) { + dump_clock(s, nest + NEST_DELTA, clk); + } +} + +static int c6x_ck_show(struct seq_file *m, void *v) +{ + struct clk *clk; + + /* + * Show clock tree; We trust nonzero usecounts equate to PSC enables... + */ + mutex_lock(&clocks_mutex); + list_for_each_entry(clk, &clocks, node) + if (!clk->parent) + dump_clock(m, 0, clk); + mutex_unlock(&clocks_mutex); + + return 0; +} + +static int c6x_ck_open(struct inode *inode, struct file *file) +{ + return single_open(file, c6x_ck_show, NULL); +} + +static const struct file_operations c6x_ck_operations = { + .open = c6x_ck_open, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, +}; + +static int __init c6x_clk_debugfs_init(void) +{ + debugfs_create_file("c6x_clocks", S_IFREG | S_IRUGO, NULL, NULL, + &c6x_ck_operations); + + return 0; +} +device_initcall(c6x_clk_debugfs_init); +#endif /* CONFIG_DEBUG_FS */ -- cgit v1.2.3