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+/*
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+ * linux/arch/arm/mach-at91rm9200/clock.c
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+ *
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+ * Copyright (C) 2005 David Brownell
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+ * Copyright (C) 2005 Ivan Kokshaysky
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+ *
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+ * This program is free software; you can redistribute it and/or modify
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+ * it under the terms of the GNU General Public License as published by
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+ * the Free Software Foundation; either version 2 of the License, or
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+ * (at your option) any later version.
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+ */
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+
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+#include <linux/module.h>
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+#include <linux/kernel.h>
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+#include <linux/init.h>
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+#include <linux/fs.h>
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+#include <linux/debugfs.h>
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+#include <linux/seq_file.h>
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+#include <linux/list.h>
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+#include <linux/errno.h>
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+#include <linux/err.h>
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+#include <linux/spinlock.h>
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+#include <linux/delay.h>
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+#include <linux/clk.h>
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+
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+#include <asm/semaphore.h>
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+#include <asm/io.h>
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+#include <asm/mach-types.h>
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+
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+#include <asm/arch/hardware.h>
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+#include <asm/arch/board.h> /* for master clock global */
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+
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+#include "generic.h"
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+
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+#undef DEBUG
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+
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+/*
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+ * There's a lot more which can be done with clocks, including cpufreq
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+ * integration, slow clock mode support (for system suspend), letting
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+ * PLLB be used at other rates (on boards that don't need USB), etc.
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+ */
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+
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+struct clk {
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+ const char *name;
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+ unsigned long rate_hz;
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+ struct clk *parent;
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+ u32 pmc_mask;
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+ void (*mode)(struct clk *, int);
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+ unsigned id:2; /* PCK0..3, or 32k/main/a/b */
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+ unsigned primary:1;
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+ unsigned pll:1;
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+ unsigned programmable:1;
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+ u16 users;
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+};
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+
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+static spinlock_t clk_lock;
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+static u32 at91_pllb_usb_init;
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+
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+/*
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+ * Four primary clock sources: two crystal oscillators (32K, main), and
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+ * two PLLs. PLLA usually runs the master clock; and PLLB must run at
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+ * 48 MHz (unless no USB function clocks are needed). The main clock and
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+ * both PLLs are turned off to run in "slow clock mode" (system suspend).
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+ */
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+static struct clk clk32k = {
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+ .name = "clk32k",
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+ .rate_hz = AT91_SLOW_CLOCK,
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+ .users = 1, /* always on */
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+ .id = 0,
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+ .primary = 1,
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+};
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+static struct clk main_clk = {
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+ .name = "main",
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+ .pmc_mask = 1 << 0, /* in PMC_SR */
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+ .users = 1,
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+ .id = 1,
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+ .primary = 1,
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+};
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+static struct clk plla = {
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+ .name = "plla",
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+ .parent = &main_clk,
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+ .pmc_mask = 1 << 1, /* in PMC_SR */
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+ .id = 2,
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+ .primary = 1,
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+ .pll = 1,
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+};
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+
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+static void pllb_mode(struct clk *clk, int is_on)
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+{
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+ u32 value;
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+
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+ if (is_on) {
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+ is_on = AT91_PMC_LOCKB;
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+ value = at91_pllb_usb_init;
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+ } else
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+ value = 0;
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+
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+ at91_sys_write(AT91_CKGR_PLLBR, value);
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+
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+ do {
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+ cpu_relax();
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+ } while ((at91_sys_read(AT91_PMC_SR) & AT91_PMC_LOCKB) != is_on);
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+}
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+
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+static struct clk pllb = {
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+ .name = "pllb",
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+ .parent = &main_clk,
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+ .pmc_mask = 1 << 2, /* in PMC_SR */
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+ .mode = pllb_mode,
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+ .id = 3,
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+ .primary = 1,
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+ .pll = 1,
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+};
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+
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+static void pmc_sys_mode(struct clk *clk, int is_on)
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+{
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+ if (is_on)
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+ at91_sys_write(AT91_PMC_SCER, clk->pmc_mask);
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+ else
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+ at91_sys_write(AT91_PMC_SCDR, clk->pmc_mask);
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+}
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+
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+/* USB function clocks (PLLB must be 48 MHz) */
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+static struct clk udpck = {
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+ .name = "udpck",
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+ .parent = &pllb,
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+ .pmc_mask = AT91_PMC_UDP,
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+ .mode = pmc_sys_mode,
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+};
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+static struct clk uhpck = {
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+ .name = "uhpck",
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+ .parent = &pllb,
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+ .pmc_mask = AT91_PMC_UHP,
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+ .mode = pmc_sys_mode,
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+};
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+
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+#ifdef CONFIG_AT91_PROGRAMMABLE_CLOCKS
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+/*
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+ * The four programmable clocks can be parented by any primary clock.
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+ * You must configure pin multiplexing to bring these signals out.
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+ */
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+static struct clk pck0 = {
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+ .name = "pck0",
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+ .pmc_mask = AT91_PMC_PCK0,
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+ .mode = pmc_sys_mode,
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+ .programmable = 1,
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+ .id = 0,
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+};
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+static struct clk pck1 = {
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+ .name = "pck1",
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+ .pmc_mask = AT91_PMC_PCK1,
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+ .mode = pmc_sys_mode,
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+ .programmable = 1,
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+ .id = 1,
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+};
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+static struct clk pck2 = {
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+ .name = "pck2",
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+ .pmc_mask = AT91_PMC_PCK2,
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+ .mode = pmc_sys_mode,
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+ .programmable = 1,
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+ .id = 2,
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+};
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+static struct clk pck3 = {
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+ .name = "pck3",
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+ .pmc_mask = AT91_PMC_PCK3,
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+ .mode = pmc_sys_mode,
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+ .programmable = 1,
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+ .id = 3,
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+};
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+#endif /* CONFIG_AT91_PROGRAMMABLE_CLOCKS */
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+
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+
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+/*
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+ * The master clock is divided from the CPU clock (by 1-4). It's used for
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+ * memory, interfaces to on-chip peripherals, the AIC, and sometimes more
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+ * (e.g baud rate generation). It's sourced from one of the primary clocks.
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+ */
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+static struct clk mck = {
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+ .name = "mck",
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+ .pmc_mask = 1 << 3, /* in PMC_SR */
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+ .users = 1, /* (must be) always on */
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+};
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+
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+static void pmc_periph_mode(struct clk *clk, int is_on)
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+{
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+ if (is_on)
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+ at91_sys_write(AT91_PMC_PCER, clk->pmc_mask);
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+ else
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+ at91_sys_write(AT91_PMC_PCDR, clk->pmc_mask);
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+}
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+
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+static struct clk udc_clk = {
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+ .name = "udc_clk",
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+ .parent = &mck,
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+ .pmc_mask = 1 << AT91_ID_UDP,
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+ .mode = pmc_periph_mode,
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+};
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+static struct clk ohci_clk = {
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+ .name = "ohci_clk",
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+ .parent = &mck,
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+ .pmc_mask = 1 << AT91_ID_UHP,
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+ .mode = pmc_periph_mode,
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+};
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+
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+static struct clk *const clock_list[] = {
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+ /* four primary clocks -- MUST BE FIRST! */
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+ &clk32k,
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+ &main_clk,
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+ &plla,
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+ &pllb,
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+
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+ /* PLLB children (USB) */
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+ &udpck,
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+ &uhpck,
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+
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+#ifdef CONFIG_AT91_PROGRAMMABLE_CLOCKS
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+ /* programmable clocks */
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+ &pck0,
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+ &pck1,
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+ &pck2,
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+ &pck3,
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+#endif /* CONFIG_AT91_PROGRAMMABLE_CLOCKS */
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+
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+ /* MCK and peripherals */
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+ &mck,
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+ // usart0..usart3
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+ // mmc
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+ &udc_clk,
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+ // i2c
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+ // spi
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+ // ssc0..ssc2
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+ // tc0..tc5
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+ &ohci_clk,
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+ // ether
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+};
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+
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+
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+/* clocks are all static for now; no refcounting necessary */
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+struct clk *clk_get(struct device *dev, const char *id)
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+{
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+ int i;
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+
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+ for (i = 0; i < ARRAY_SIZE(clock_list); i++) {
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+ if (strcmp(id, clock_list[i]->name) == 0)
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+ return clock_list[i];
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+ }
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+
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+ return ERR_PTR(-ENOENT);
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+}
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+EXPORT_SYMBOL(clk_get);
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+
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+void clk_put(struct clk *clk)
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+{
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+}
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+EXPORT_SYMBOL(clk_put);
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+
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+static void __clk_enable(struct clk *clk)
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+{
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+ if (clk->parent)
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+ __clk_enable(clk->parent);
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+ if (clk->users++ == 0 && clk->mode)
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+ clk->mode(clk, 1);
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+}
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+
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+int clk_enable(struct clk *clk)
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+{
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+ unsigned long flags;
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+
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+ spin_lock_irqsave(&clk_lock, flags);
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+ __clk_enable(clk);
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+ spin_unlock_irqrestore(&clk_lock, flags);
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+ return 0;
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+}
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+EXPORT_SYMBOL(clk_enable);
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+
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+static void __clk_disable(struct clk *clk)
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+{
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+ BUG_ON(clk->users == 0);
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+ if (--clk->users == 0 && clk->mode)
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+ clk->mode(clk, 0);
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+ if (clk->parent)
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+ __clk_disable(clk->parent);
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+}
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+
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+void clk_disable(struct clk *clk)
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+{
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+ unsigned long flags;
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+
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+ spin_lock_irqsave(&clk_lock, flags);
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+ __clk_disable(clk);
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+ spin_unlock_irqrestore(&clk_lock, flags);
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+}
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+EXPORT_SYMBOL(clk_disable);
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+
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+unsigned long clk_get_rate(struct clk *clk)
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+{
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+ unsigned long flags;
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+ unsigned long rate;
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+
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+ spin_lock_irqsave(&clk_lock, flags);
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+ for (;;) {
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+ rate = clk->rate_hz;
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+ if (rate || !clk->parent)
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+ break;
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+ clk = clk->parent;
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+ }
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+ spin_unlock_irqrestore(&clk_lock, flags);
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+ return rate;
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+}
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+EXPORT_SYMBOL(clk_get_rate);
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+
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+/*------------------------------------------------------------------------*/
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+
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+#ifdef CONFIG_AT91_PROGRAMMABLE_CLOCKS
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+
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+/*
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+ * For now, only the programmable clocks support reparenting (MCK could
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+ * do this too, with care) or rate changing (the PLLs could do this too,
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+ * ditto MCK but that's more for cpufreq). Drivers may reparent to get
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+ * a better rate match; we don't.
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+ */
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+
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+long clk_round_rate(struct clk *clk, unsigned long rate)
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+{
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+ unsigned long flags;
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+ unsigned prescale;
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+ unsigned long actual;
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+
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+ if (!clk->programmable)
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+ return -EINVAL;
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+ spin_lock_irqsave(&clk_lock, flags);
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+
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+ actual = clk->parent->rate_hz;
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+ for (prescale = 0; prescale < 7; prescale++) {
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+ if (actual && actual <= rate)
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+ break;
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+ actual >>= 1;
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+ }
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+
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+ spin_unlock_irqrestore(&clk_lock, flags);
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+ return (prescale < 7) ? actual : -ENOENT;
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+}
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+EXPORT_SYMBOL(clk_round_rate);
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+
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+int clk_set_rate(struct clk *clk, unsigned long rate)
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+{
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+ unsigned long flags;
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+ unsigned prescale;
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+ unsigned long actual;
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+
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+ if (!clk->programmable)
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+ return -EINVAL;
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+ if (clk->users)
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+ return -EBUSY;
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+ spin_lock_irqsave(&clk_lock, flags);
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+
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+ actual = clk->parent->rate_hz;
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+ for (prescale = 0; prescale < 7; prescale++) {
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+ if (actual && actual <= rate) {
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+ u32 pckr;
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+
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+ pckr = at91_sys_read(AT91_PMC_PCKR(clk->id));
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+ pckr &= 0x03;
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+ pckr |= prescale << 2;
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+ at91_sys_write(AT91_PMC_PCKR(clk->id), pckr);
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+ clk->rate_hz = actual;
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+ break;
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+ }
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+ actual >>= 1;
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+ }
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+
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+ spin_unlock_irqrestore(&clk_lock, flags);
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+ return (prescale < 7) ? actual : -ENOENT;
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+}
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+EXPORT_SYMBOL(clk_set_rate);
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+
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+struct clk *clk_get_parent(struct clk *clk)
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+{
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+ return clk->parent;
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+}
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+EXPORT_SYMBOL(clk_get_parent);
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+
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+int clk_set_parent(struct clk *clk, struct clk *parent)
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+{
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+ unsigned long flags;
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+
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+ if (clk->users)
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+ return -EBUSY;
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+ if (!parent->primary || !clk->programmable)
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+ return -EINVAL;
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+ spin_lock_irqsave(&clk_lock, flags);
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+
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+ clk->rate_hz = parent->rate_hz;
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+ clk->parent = parent;
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+ at91_sys_write(AT91_PMC_PCKR(clk->id), parent->id);
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+
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+ spin_unlock_irqrestore(&clk_lock, flags);
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+ return 0;
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+}
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+EXPORT_SYMBOL(clk_set_parent);
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+
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+#endif /* CONFIG_AT91_PROGRAMMABLE_CLOCKS */
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+
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+/*------------------------------------------------------------------------*/
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+
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+#ifdef CONFIG_DEBUG_FS
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+
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+static int at91_clk_show(struct seq_file *s, void *unused)
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+{
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+ u32 scsr, pcsr, sr;
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+ unsigned i;
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+
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+ seq_printf(s, "SCSR = %8x\n", scsr = at91_sys_read(AT91_PMC_SCSR));
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+ seq_printf(s, "PCSR = %8x\n", pcsr = at91_sys_read(AT91_PMC_PCSR));
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+
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+ seq_printf(s, "MOR = %8x\n", at91_sys_read(AT91_CKGR_MOR));
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+ seq_printf(s, "MCFR = %8x\n", at91_sys_read(AT91_CKGR_MCFR));
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+ seq_printf(s, "PLLA = %8x\n", at91_sys_read(AT91_CKGR_PLLAR));
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+ seq_printf(s, "PLLB = %8x\n", at91_sys_read(AT91_CKGR_PLLBR));
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+
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+ seq_printf(s, "MCKR = %8x\n", at91_sys_read(AT91_PMC_MCKR));
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+ for (i = 0; i < 4; i++)
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+ seq_printf(s, "PCK%d = %8x\n", i, at91_sys_read(AT91_PMC_PCKR(i)));
|
|
|
+ seq_printf(s, "SR = %8x\n", sr = at91_sys_read(AT91_PMC_SR));
|
|
|
+
|
|
|
+ seq_printf(s, "\n");
|
|
|
+
|
|
|
+ for (i = 0; i < ARRAY_SIZE(clock_list); i++) {
|
|
|
+ char *state;
|
|
|
+ struct clk *clk = clock_list[i];
|
|
|
+
|
|
|
+ if (clk->mode == pmc_sys_mode)
|
|
|
+ state = (scsr & clk->pmc_mask) ? "on" : "off";
|
|
|
+ else if (clk->mode == pmc_periph_mode)
|
|
|
+ state = (pcsr & clk->pmc_mask) ? "on" : "off";
|
|
|
+ else if (clk->pmc_mask)
|
|
|
+ state = (sr & clk->pmc_mask) ? "on" : "off";
|
|
|
+ else if (clk == &clk32k || clk == &main_clk)
|
|
|
+ state = "on";
|
|
|
+ else
|
|
|
+ state = "";
|
|
|
+
|
|
|
+ seq_printf(s, "%-10s users=%d %-3s %9ld Hz %s\n",
|
|
|
+ clk->name, clk->users, state, clk_get_rate(clk),
|
|
|
+ clk->parent ? clk->parent->name : "");
|
|
|
+ }
|
|
|
+ return 0;
|
|
|
+}
|
|
|
+
|
|
|
+static int at91_clk_open(struct inode *inode, struct file *file)
|
|
|
+{
|
|
|
+ return single_open(file, at91_clk_show, NULL);
|
|
|
+}
|
|
|
+
|
|
|
+static struct file_operations at91_clk_operations = {
|
|
|
+ .open = at91_clk_open,
|
|
|
+ .read = seq_read,
|
|
|
+ .llseek = seq_lseek,
|
|
|
+ .release = single_release,
|
|
|
+};
|
|
|
+
|
|
|
+static int __init at91_clk_debugfs_init(void)
|
|
|
+{
|
|
|
+ /* /sys/kernel/debug/at91_clk */
|
|
|
+ (void) debugfs_create_file("at91_clk", S_IFREG | S_IRUGO, NULL, NULL, &at91_clk_operations);
|
|
|
+
|
|
|
+ return 0;
|
|
|
+}
|
|
|
+postcore_initcall(at91_clk_debugfs_init);
|
|
|
+
|
|
|
+#endif
|
|
|
+
|
|
|
+/*------------------------------------------------------------------------*/
|
|
|
+
|
|
|
+static u32 __init at91_pll_rate(struct clk *pll, u32 freq, u32 reg)
|
|
|
+{
|
|
|
+ unsigned mul, div;
|
|
|
+
|
|
|
+ div = reg & 0xff;
|
|
|
+ mul = (reg >> 16) & 0x7ff;
|
|
|
+ if (div && mul) {
|
|
|
+ freq /= div;
|
|
|
+ freq *= mul + 1;
|
|
|
+ } else
|
|
|
+ freq = 0;
|
|
|
+ if (pll == &pllb && (reg & (1 << 28)))
|
|
|
+ freq /= 2;
|
|
|
+ return freq;
|
|
|
+}
|
|
|
+
|
|
|
+static unsigned __init at91_pll_calc(unsigned main_freq, unsigned out_freq)
|
|
|
+{
|
|
|
+ unsigned i, div = 0, mul = 0, diff = 1 << 30;
|
|
|
+ unsigned ret = (out_freq > 155000000) ? 0xbe00 : 0x3e00;
|
|
|
+
|
|
|
+ /* PLL output max 240 MHz (or 180 MHz per errata) */
|
|
|
+ if (out_freq > 240000000)
|
|
|
+ goto fail;
|
|
|
+
|
|
|
+ for (i = 1; i < 256; i++) {
|
|
|
+ int diff1;
|
|
|
+ unsigned input, mul1;
|
|
|
+
|
|
|
+ /*
|
|
|
+ * PLL input between 1MHz and 32MHz per spec, but lower
|
|
|
+ * frequences seem necessary in some cases so allow 100K.
|
|
|
+ */
|
|
|
+ input = main_freq / i;
|
|
|
+ if (input < 100000)
|
|
|
+ continue;
|
|
|
+ if (input > 32000000)
|
|
|
+ continue;
|
|
|
+
|
|
|
+ mul1 = out_freq / input;
|
|
|
+ if (mul1 > 2048)
|
|
|
+ continue;
|
|
|
+ if (mul1 < 2)
|
|
|
+ goto fail;
|
|
|
+
|
|
|
+ diff1 = out_freq - input * mul1;
|
|
|
+ if (diff1 < 0)
|
|
|
+ diff1 = -diff1;
|
|
|
+ if (diff > diff1) {
|
|
|
+ diff = diff1;
|
|
|
+ div = i;
|
|
|
+ mul = mul1;
|
|
|
+ if (diff == 0)
|
|
|
+ break;
|
|
|
+ }
|
|
|
+ }
|
|
|
+ if (i == 256 && diff > (out_freq >> 5))
|
|
|
+ goto fail;
|
|
|
+ return ret | ((mul - 1) << 16) | div;
|
|
|
+fail:
|
|
|
+ return 0;
|
|
|
+}
|
|
|
+
|
|
|
+int __init at91_clock_init(unsigned long main_clock)
|
|
|
+{
|
|
|
+ unsigned tmp, freq, mckr;
|
|
|
+
|
|
|
+ spin_lock_init(&clk_lock);
|
|
|
+
|
|
|
+ /*
|
|
|
+ * When the bootloader initialized the main oscillator correctly,
|
|
|
+ * there's no problem using the cycle counter. But if it didn't,
|
|
|
+ * or when using oscillator bypass mode, we must be told the speed
|
|
|
+ * of the main clock.
|
|
|
+ */
|
|
|
+ if (!main_clock) {
|
|
|
+ do {
|
|
|
+ tmp = at91_sys_read(AT91_CKGR_MCFR);
|
|
|
+ } while (!(tmp & 0x10000));
|
|
|
+ main_clock = (tmp & 0xffff) * (AT91_SLOW_CLOCK / 16);
|
|
|
+ }
|
|
|
+ main_clk.rate_hz = main_clock;
|
|
|
+
|
|
|
+ /* report if PLLA is more than mildly overclocked */
|
|
|
+ plla.rate_hz = at91_pll_rate(&plla, main_clock, at91_sys_read(AT91_CKGR_PLLAR));
|
|
|
+ if (plla.rate_hz > 209000000)
|
|
|
+ pr_info("Clocks: PLLA overclocked, %ld MHz\n", plla.rate_hz / 1000000);
|
|
|
+
|
|
|
+ /*
|
|
|
+ * USB clock init: choose 48 MHz PLLB value, turn all clocks off,
|
|
|
+ * disable 48MHz clock during usb peripheral suspend.
|
|
|
+ *
|
|
|
+ * REVISIT: assumes MCK doesn't derive from PLLB!
|
|
|
+ */
|
|
|
+ at91_pllb_usb_init = at91_pll_calc(main_clock, 48000000 * 2) | 0x10000000;
|
|
|
+ pllb.rate_hz = at91_pll_rate(&pllb, main_clock, at91_pllb_usb_init);
|
|
|
+ at91_sys_write(AT91_PMC_PCDR, (1 << AT91_ID_UHP) | (1 << AT91_ID_UDP));
|
|
|
+ at91_sys_write(AT91_PMC_SCDR, AT91_PMC_UHP | AT91_PMC_UDP);
|
|
|
+ at91_sys_write(AT91_CKGR_PLLBR, 0);
|
|
|
+ at91_sys_write(AT91_PMC_SCER, AT91_PMC_MCKUDP);
|
|
|
+
|
|
|
+ /*
|
|
|
+ * MCK and CPU derive from one of those primary clocks.
|
|
|
+ * For now, assume this parentage won't change.
|
|
|
+ */
|
|
|
+ mckr = at91_sys_read(AT91_PMC_MCKR);
|
|
|
+ mck.parent = clock_list[mckr & AT91_PMC_CSS];
|
|
|
+ mck.parent->users++;
|
|
|
+ freq = mck.parent->rate_hz;
|
|
|
+ freq /= (1 << ((mckr >> 2) & 3)); /* prescale */
|
|
|
+ mck.rate_hz = freq / (1 + ((mckr >> 8) & 3)); /* mdiv */
|
|
|
+
|
|
|
+ printk("Clocks: CPU %u MHz, master %u MHz, main %u.%03u MHz\n",
|
|
|
+ freq / 1000000, (unsigned) mck.rate_hz / 1000000,
|
|
|
+ (unsigned) main_clock / 1000000,
|
|
|
+ ((unsigned) main_clock % 1000000) / 1000);
|
|
|
+
|
|
|
+ /* FIXME get rid of master_clock global */
|
|
|
+ at91_master_clock = mck.rate_hz;
|
|
|
+
|
|
|
+#ifdef CONFIG_AT91_PROGRAMMABLE_CLOCKS
|
|
|
+ /* establish PCK0..PCK3 parentage */
|
|
|
+ for (tmp = 0; tmp < ARRAY_SIZE(clock_list); tmp++) {
|
|
|
+ struct clk *clk = clock_list[tmp], *parent;
|
|
|
+ u32 pckr;
|
|
|
+
|
|
|
+ if (!clk->programmable)
|
|
|
+ continue;
|
|
|
+
|
|
|
+ pckr = at91_sys_read(AT91_PMC_PCKR(clk->id));
|
|
|
+ parent = clock_list[pckr & 3];
|
|
|
+ clk->parent = parent;
|
|
|
+ clk->rate_hz = parent->rate_hz / (1 << ((pckr >> 2) & 3));
|
|
|
+ }
|
|
|
+#else
|
|
|
+ /* disable unused clocks */
|
|
|
+ at91_sys_write(AT91_PMC_SCDR, AT91_PMC_PCK0 | AT91_PMC_PCK1 | AT91_PMC_PCK2 | AT91_PMC_PCK3);
|
|
|
+#endif /* CONFIG_AT91_PROGRAMMABLE_CLOCKS */
|
|
|
+
|
|
|
+ /* FIXME several unused clocks may still be active... provide
|
|
|
+ * a CONFIG option to turn off all unused clocks at some point
|
|
|
+ * before driver init starts.
|
|
|
+ */
|
|
|
+
|
|
|
+ return 0;
|
|
|
+}
|