diff options
Diffstat (limited to 'kernel/drivers/cpufreq/s3c2412-cpufreq.c')
| -rw-r--r-- | kernel/drivers/cpufreq/s3c2412-cpufreq.c | 254 |
1 files changed, 254 insertions, 0 deletions
diff --git a/kernel/drivers/cpufreq/s3c2412-cpufreq.c b/kernel/drivers/cpufreq/s3c2412-cpufreq.c new file mode 100644 index 000000000..eb262133f --- /dev/null +++ b/kernel/drivers/cpufreq/s3c2412-cpufreq.c @@ -0,0 +1,254 @@ +/* + * Copyright 2008 Simtec Electronics + * http://armlinux.simtec.co.uk/ + * Ben Dooks <ben@simtec.co.uk> + * + * S3C2412 CPU Frequency scalling + * + * 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. +*/ + +#include <linux/init.h> +#include <linux/module.h> +#include <linux/interrupt.h> +#include <linux/ioport.h> +#include <linux/cpufreq.h> +#include <linux/device.h> +#include <linux/delay.h> +#include <linux/clk.h> +#include <linux/err.h> +#include <linux/io.h> + +#include <asm/mach/arch.h> +#include <asm/mach/map.h> + +#include <mach/regs-clock.h> +#include <mach/s3c2412.h> + +#include <plat/cpu.h> +#include <plat/cpu-freq-core.h> + +/* our clock resources. */ +static struct clk *xtal; +static struct clk *fclk; +static struct clk *hclk; +static struct clk *armclk; + +/* HDIV: 1, 2, 3, 4, 6, 8 */ + +static int s3c2412_cpufreq_calcdivs(struct s3c_cpufreq_config *cfg) +{ + unsigned int hdiv, pdiv, armdiv, dvs; + unsigned long hclk, fclk, armclk, armdiv_clk; + unsigned long hclk_max; + + fclk = cfg->freq.fclk; + armclk = cfg->freq.armclk; + hclk_max = cfg->max.hclk; + + /* We can't run hclk above armclk as at the best we have to + * have armclk and hclk in dvs mode. */ + + if (hclk_max > armclk) + hclk_max = armclk; + + s3c_freq_dbg("%s: fclk=%lu, armclk=%lu, hclk_max=%lu\n", + __func__, fclk, armclk, hclk_max); + s3c_freq_dbg("%s: want f=%lu, arm=%lu, h=%lu, p=%lu\n", + __func__, cfg->freq.fclk, cfg->freq.armclk, + cfg->freq.hclk, cfg->freq.pclk); + + armdiv = fclk / armclk; + + if (armdiv < 1) + armdiv = 1; + if (armdiv > 2) + armdiv = 2; + + cfg->divs.arm_divisor = armdiv; + armdiv_clk = fclk / armdiv; + + hdiv = armdiv_clk / hclk_max; + if (hdiv < 1) + hdiv = 1; + + cfg->freq.hclk = hclk = armdiv_clk / hdiv; + + /* set dvs depending on whether we reached armclk or not. */ + cfg->divs.dvs = dvs = armclk < armdiv_clk; + + /* update the actual armclk we achieved. */ + cfg->freq.armclk = dvs ? hclk : armdiv_clk; + + s3c_freq_dbg("%s: armclk %lu, hclk %lu, armdiv %d, hdiv %d, dvs %d\n", + __func__, armclk, hclk, armdiv, hdiv, cfg->divs.dvs); + + if (hdiv > 4) + goto invalid; + + pdiv = (hclk > cfg->max.pclk) ? 2 : 1; + + if ((hclk / pdiv) > cfg->max.pclk) + pdiv++; + + cfg->freq.pclk = hclk / pdiv; + + s3c_freq_dbg("%s: pdiv %d\n", __func__, pdiv); + + if (pdiv > 2) + goto invalid; + + pdiv *= hdiv; + + /* store the result, and then return */ + + cfg->divs.h_divisor = hdiv * armdiv; + cfg->divs.p_divisor = pdiv * armdiv; + + return 0; + +invalid: + return -EINVAL; +} + +static void s3c2412_cpufreq_setdivs(struct s3c_cpufreq_config *cfg) +{ + unsigned long clkdiv; + unsigned long olddiv; + + olddiv = clkdiv = __raw_readl(S3C2410_CLKDIVN); + + /* clear off current clock info */ + + clkdiv &= ~S3C2412_CLKDIVN_ARMDIVN; + clkdiv &= ~S3C2412_CLKDIVN_HDIVN_MASK; + clkdiv &= ~S3C2412_CLKDIVN_PDIVN; + + if (cfg->divs.arm_divisor == 2) + clkdiv |= S3C2412_CLKDIVN_ARMDIVN; + + clkdiv |= ((cfg->divs.h_divisor / cfg->divs.arm_divisor) - 1); + + if (cfg->divs.p_divisor != cfg->divs.h_divisor) + clkdiv |= S3C2412_CLKDIVN_PDIVN; + + s3c_freq_dbg("%s: div %08lx => %08lx\n", __func__, olddiv, clkdiv); + __raw_writel(clkdiv, S3C2410_CLKDIVN); + + clk_set_parent(armclk, cfg->divs.dvs ? hclk : fclk); +} + +static void s3c2412_cpufreq_setrefresh(struct s3c_cpufreq_config *cfg) +{ + struct s3c_cpufreq_board *board = cfg->board; + unsigned long refresh; + + s3c_freq_dbg("%s: refresh %u ns, hclk %lu\n", __func__, + board->refresh, cfg->freq.hclk); + + /* Reduce both the refresh time (in ns) and the frequency (in MHz) + * by 10 each to ensure that we do not overflow 32 bit numbers. This + * should work for HCLK up to 133MHz and refresh period up to 30usec. + */ + + refresh = (board->refresh / 10); + refresh *= (cfg->freq.hclk / 100); + refresh /= (1 * 1000 * 1000); /* 10^6 */ + + s3c_freq_dbg("%s: setting refresh 0x%08lx\n", __func__, refresh); + __raw_writel(refresh, S3C2412_REFRESH); +} + +/* set the default cpu frequency information, based on an 200MHz part + * as we have no other way of detecting the speed rating in software. + */ + +static struct s3c_cpufreq_info s3c2412_cpufreq_info = { + .max = { + .fclk = 200000000, + .hclk = 100000000, + .pclk = 50000000, + }, + + .latency = 5000000, /* 5ms */ + + .locktime_m = 150, + .locktime_u = 150, + .locktime_bits = 16, + + .name = "s3c2412", + .set_refresh = s3c2412_cpufreq_setrefresh, + .set_divs = s3c2412_cpufreq_setdivs, + .calc_divs = s3c2412_cpufreq_calcdivs, + + .calc_iotiming = s3c2412_iotiming_calc, + .set_iotiming = s3c2412_iotiming_set, + .get_iotiming = s3c2412_iotiming_get, + + .debug_io_show = s3c_cpufreq_debugfs_call(s3c2412_iotiming_debugfs), +}; + +static int s3c2412_cpufreq_add(struct device *dev, + struct subsys_interface *sif) +{ + unsigned long fclk_rate; + + hclk = clk_get(NULL, "hclk"); + if (IS_ERR(hclk)) { + printk(KERN_ERR "%s: cannot find hclk clock\n", __func__); + return -ENOENT; + } + + fclk = clk_get(NULL, "fclk"); + if (IS_ERR(fclk)) { + printk(KERN_ERR "%s: cannot find fclk clock\n", __func__); + goto err_fclk; + } + + fclk_rate = clk_get_rate(fclk); + if (fclk_rate > 200000000) { + printk(KERN_INFO + "%s: fclk %ld MHz, assuming 266MHz capable part\n", + __func__, fclk_rate / 1000000); + s3c2412_cpufreq_info.max.fclk = 266000000; + s3c2412_cpufreq_info.max.hclk = 133000000; + s3c2412_cpufreq_info.max.pclk = 66000000; + } + + armclk = clk_get(NULL, "armclk"); + if (IS_ERR(armclk)) { + printk(KERN_ERR "%s: cannot find arm clock\n", __func__); + goto err_armclk; + } + + xtal = clk_get(NULL, "xtal"); + if (IS_ERR(xtal)) { + printk(KERN_ERR "%s: cannot find xtal clock\n", __func__); + goto err_xtal; + } + + return s3c_cpufreq_register(&s3c2412_cpufreq_info); + +err_xtal: + clk_put(armclk); +err_armclk: + clk_put(fclk); +err_fclk: + clk_put(hclk); + + return -ENOENT; +} + +static struct subsys_interface s3c2412_cpufreq_interface = { + .name = "s3c2412_cpufreq", + .subsys = &s3c2412_subsys, + .add_dev = s3c2412_cpufreq_add, +}; + +static int s3c2412_cpufreq_init(void) +{ + return subsys_interface_register(&s3c2412_cpufreq_interface); +} +arch_initcall(s3c2412_cpufreq_init); |