diff options
Diffstat (limited to 'arch/arm/plat-s3c24xx/s3c2412-iotiming.c')
| -rw-r--r-- | arch/arm/plat-s3c24xx/s3c2412-iotiming.c | 285 |
1 files changed, 285 insertions, 0 deletions
diff --git a/arch/arm/plat-s3c24xx/s3c2412-iotiming.c b/arch/arm/plat-s3c24xx/s3c2412-iotiming.c new file mode 100644 index 000000000000..fd45e47facbc --- /dev/null +++ b/arch/arm/plat-s3c24xx/s3c2412-iotiming.c @@ -0,0 +1,285 @@ +/* linux/arch/arm/plat-s3c24xx/s3c2412-iotiming.c + * + * Copyright (c) 2006,2008 Simtec Electronics + * http://armlinux.simtec.co.uk/ + * Ben Dooks <ben@simtec.co.uk> + * + * S3C2412/S3C2443 (PL093 based) IO timing support + * + * 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/seq_file.h> +#include <linux/sysdev.h> +#include <linux/delay.h> +#include <linux/clk.h> +#include <linux/err.h> + +#include <linux/amba/pl093.h> + +#include <asm/mach/arch.h> +#include <asm/mach/map.h> + +#include <mach/regs-s3c2412-mem.h> + +#include <plat/cpu.h> +#include <plat/cpu-freq-core.h> +#include <plat/clock.h> + +#define print_ns(x) ((x) / 10), ((x) % 10) + +/** + * s3c2412_print_timing - print timing infromation via printk. + * @pfx: The prefix to print each line with. + * @iot: The IO timing information + */ +static void s3c2412_print_timing(const char *pfx, struct s3c_iotimings *iot) +{ + struct s3c2412_iobank_timing *bt; + unsigned int bank; + + for (bank = 0; bank < MAX_BANKS; bank++) { + bt = iot->bank[bank].io_2412; + if (!bt) + continue; + + printk(KERN_DEBUG "%s: %d: idcy=%d.%d wstrd=%d.%d wstwr=%d,%d" + "wstoen=%d.%d wstwen=%d.%d wstbrd=%d.%d\n", pfx, bank, + print_ns(bt->idcy), + print_ns(bt->wstrd), + print_ns(bt->wstwr), + print_ns(bt->wstoen), + print_ns(bt->wstwen), + print_ns(bt->wstbrd)); + } +} + +/** + * to_div - turn a cycle length into a divisor setting. + * @cyc_tns: The cycle time in 10ths of nanoseconds. + * @clk_tns: The clock period in 10ths of nanoseconds. + */ +static inline unsigned int to_div(unsigned int cyc_tns, unsigned int clk_tns) +{ + return cyc_tns ? DIV_ROUND_UP(cyc_tns, clk_tns) : 0; +} + +/** + * calc_timing - calculate timing divisor value and check in range. + * @hwtm: The hardware timing in 10ths of nanoseconds. + * @clk_tns: The clock period in 10ths of nanoseconds. + * @err: Pointer to err variable to update in event of failure. + */ +static unsigned int calc_timing(unsigned int hwtm, unsigned int clk_tns, + unsigned int *err) +{ + unsigned int ret = to_div(hwtm, clk_tns); + + if (ret > 0xf) + *err = -EINVAL; + + return ret; +} + +/** + * s3c2412_calc_bank - calculate the bank divisor settings. + * @cfg: The current frequency configuration. + * @bt: The bank timing. + */ +static int s3c2412_calc_bank(struct s3c_cpufreq_config *cfg, + struct s3c2412_iobank_timing *bt) +{ + unsigned int hclk = cfg->freq.hclk_tns; + int err = 0; + + bt->smbidcyr = calc_timing(bt->idcy, hclk, &err); + bt->smbwstrd = calc_timing(bt->wstrd, hclk, &err); + bt->smbwstwr = calc_timing(bt->wstwr, hclk, &err); + bt->smbwstoen = calc_timing(bt->wstoen, hclk, &err); + bt->smbwstwen = calc_timing(bt->wstwen, hclk, &err); + bt->smbwstbrd = calc_timing(bt->wstbrd, hclk, &err); + + return err; +} + +/** + * s3c2412_iotiming_debugfs - debugfs show io bank timing information + * @seq: The seq_file to write output to using seq_printf(). + * @cfg: The current configuration. + * @iob: The IO bank information to decode. +*/ +void s3c2412_iotiming_debugfs(struct seq_file *seq, + struct s3c_cpufreq_config *cfg, + union s3c_iobank *iob) +{ + struct s3c2412_iobank_timing *bt = iob->io_2412; + + seq_printf(seq, + "\tRead: idcy=%d.%d wstrd=%d.%d wstwr=%d,%d" + "wstoen=%d.%d wstwen=%d.%d wstbrd=%d.%d\n", + print_ns(bt->idcy), + print_ns(bt->wstrd), + print_ns(bt->wstwr), + print_ns(bt->wstoen), + print_ns(bt->wstwen), + print_ns(bt->wstbrd)); +} + +/** + * s3c2412_iotiming_calc - calculate all the bank divisor settings. + * @cfg: The current frequency configuration. + * @iot: The bank timing information. + * + * Calculate the timing information for all the banks that are + * configured as IO, using s3c2412_calc_bank(). + */ +int s3c2412_iotiming_calc(struct s3c_cpufreq_config *cfg, + struct s3c_iotimings *iot) +{ + struct s3c2412_iobank_timing *bt; + int bank; + int ret; + + for (bank = 0; bank < MAX_BANKS; bank++) { + bt = iot->bank[bank].io_2412; + if (!bt) + continue; + + ret = s3c2412_calc_bank(cfg, bt); + if (ret) { + printk(KERN_ERR "%s: cannot calculate bank %d io\n", + __func__, bank); + goto err; + } + } + + return 0; + err: + return ret; +} + +/** + * s3c2412_iotiming_set - set the timing information + * @cfg: The current frequency configuration. + * @iot: The bank timing information. + * + * Set the IO bank information from the details calculated earlier from + * calling s3c2412_iotiming_calc(). + */ +void s3c2412_iotiming_set(struct s3c_cpufreq_config *cfg, + struct s3c_iotimings *iot) +{ + struct s3c2412_iobank_timing *bt; + void __iomem *regs; + int bank; + + /* set the io timings from the specifier */ + + for (bank = 0; bank < MAX_BANKS; bank++) { + bt = iot->bank[bank].io_2412; + if (!bt) + continue; + + regs = S3C2412_SSMC_BANK(bank); + + __raw_writel(bt->smbidcyr, regs + SMBIDCYR); + __raw_writel(bt->smbwstrd, regs + SMBWSTRDR); + __raw_writel(bt->smbwstwr, regs + SMBWSTWRR); + __raw_writel(bt->smbwstoen, regs + SMBWSTOENR); + __raw_writel(bt->smbwstwen, regs + SMBWSTWENR); + __raw_writel(bt->smbwstbrd, regs + SMBWSTBRDR); + } +} + +static inline unsigned int s3c2412_decode_timing(unsigned int clock, u32 reg) +{ + return (reg & 0xf) * clock; +} + +static void s3c2412_iotiming_getbank(struct s3c_cpufreq_config *cfg, + struct s3c2412_iobank_timing *bt, + unsigned int bank) +{ + unsigned long clk = cfg->freq.hclk_tns; /* ssmc clock??? */ + void __iomem *regs = S3C2412_SSMC_BANK(bank); + + bt->idcy = s3c2412_decode_timing(clk, __raw_readl(regs + SMBIDCYR)); + bt->wstrd = s3c2412_decode_timing(clk, __raw_readl(regs + SMBWSTRDR)); + bt->wstoen = s3c2412_decode_timing(clk, __raw_readl(regs + SMBWSTOENR)); + bt->wstwen = s3c2412_decode_timing(clk, __raw_readl(regs + SMBWSTWENR)); + bt->wstbrd = s3c2412_decode_timing(clk, __raw_readl(regs + SMBWSTBRDR)); +} + +/** + * bank_is_io - return true if bank is (possibly) IO. + * @bank: The bank number. + * @bankcfg: The value of S3C2412_EBI_BANKCFG. + */ +static inline bool bank_is_io(unsigned int bank, u32 bankcfg) +{ + if (bank < 2) + return true; + + return !(bankcfg & (1 << bank)); +} + +int s3c2412_iotiming_get(struct s3c_cpufreq_config *cfg, + struct s3c_iotimings *timings) +{ + struct s3c2412_iobank_timing *bt; + u32 bankcfg = __raw_readl(S3C2412_EBI_BANKCFG); + unsigned int bank; + + /* look through all banks to see what is currently set. */ + + for (bank = 0; bank < MAX_BANKS; bank++) { + if (!bank_is_io(bank, bankcfg)) + continue; + + bt = kzalloc(sizeof(struct s3c2412_iobank_timing), GFP_KERNEL); + if (!bt) { + printk(KERN_ERR "%s: no memory for bank\n", __func__); + return -ENOMEM; + } + + timings->bank[bank].io_2412 = bt; + s3c2412_iotiming_getbank(cfg, bt, bank); + } + + s3c2412_print_timing("get", timings); + return 0; +} + +/* this is in here as it is so small, it doesn't currently warrant a file + * to itself. We expect that any s3c24xx needing this is going to also + * need the iotiming support. + */ +void s3c2412_cpufreq_setrefresh(struct s3c_cpufreq_config *cfg) +{ + struct s3c_cpufreq_board *board = cfg->board; + u32 refresh; + + WARN_ON(board == NULL); + + /* Reduce both the refresh time (in ns) and the frequency (in MHz) + * down 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 = (cfg->freq.hclk / 100) * (board->refresh / 10); + refresh = DIV_ROUND_UP(refresh, (1000 * 1000)); /* apply scale */ + refresh &= ((1 << 16) - 1); + + s3c_freq_dbg("%s: refresh value %u\n", __func__, (unsigned int)refresh); + + __raw_writel(refresh, S3C2412_REFRESH); +} |