diff options
Diffstat (limited to 'arch/arm/plat-s3c24xx/s3c2410-iotiming.c')
| -rw-r--r-- | arch/arm/plat-s3c24xx/s3c2410-iotiming.c | 477 |
1 files changed, 477 insertions, 0 deletions
diff --git a/arch/arm/plat-s3c24xx/s3c2410-iotiming.c b/arch/arm/plat-s3c24xx/s3c2410-iotiming.c new file mode 100644 index 0000000..d0a3a14 --- /dev/null +++ b/arch/arm/plat-s3c24xx/s3c2410-iotiming.c @@ -0,0 +1,477 @@ +/* linux/arch/arm/plat-s3c24xx/s3c2410-iotiming.c + * + * Copyright (c) 2006,2008,2009 Simtec Electronics + * http://armlinux.simtec.co.uk/ + * Ben Dooks <ben@simtec.co.uk> + * + * S3C24XX CPU Frequency scaling - IO timing for S3C2410/S3C2440/S3C2442 + * + * 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/kernel.h> +#include <linux/errno.h> +#include <linux/cpufreq.h> +#include <linux/seq_file.h> +#include <linux/io.h> + +#include <mach/map.h> +#include <mach/regs-mem.h> +#include <mach/regs-clock.h> + +#include <plat/cpu-freq-core.h> + +#define print_ns(x) ((x) / 10), ((x) % 10) + +/** + * s3c2410_print_timing - print bank timing data for debug purposes + * @pfx: The prefix to put on the output + * @timings: The timing inforamtion to print. +*/ +static void s3c2410_print_timing(const char *pfx, + struct s3c_iotimings *timings) +{ + struct s3c2410_iobank_timing *bt; + int bank; + + for (bank = 0; bank < MAX_BANKS; bank++) { + bt = timings->bank[bank].io_2410; + if (!bt) + continue; + + printk(KERN_DEBUG "%s %d: Tacs=%d.%d, Tcos=%d.%d, Tacc=%d.%d, " + "Tcoh=%d.%d, Tcah=%d.%d\n", pfx, bank, + print_ns(bt->tacs), + print_ns(bt->tcos), + print_ns(bt->tacc), + print_ns(bt->tcoh), + print_ns(bt->tcah)); + } +} + +/** + * bank_reg - convert bank number to pointer to the control register. + * @bank: The IO bank number. + */ +static inline void __iomem *bank_reg(unsigned int bank) +{ + return S3C2410_BANKCON0 + (bank << 2); +} + +/** + * bank_is_io - test whether bank is used for IO + * @bankcon: The bank control register. + * + * This is a simplistic test to see if any BANKCON[x] is not an IO + * bank. It currently does not take into account whether BWSCON has + * an illegal width-setting in it, or if the pin connected to nCS[x] + * is actually being handled as a chip-select. + */ +static inline int bank_is_io(unsigned long bankcon) +{ + return !(bankcon & S3C2410_BANKCON_SDRAM); +} + +/** + * to_div - convert cycle time to divisor + * @cyc: The cycle time, in 10ths of nanoseconds. + * @hclk_tns: The cycle time for HCLK, in 10ths of nanoseconds. + * + * Convert the given cycle time into the divisor to use to obtain it from + * HCLK. +*/ +static inline unsigned int to_div(unsigned int cyc, unsigned int hclk_tns) +{ + if (cyc == 0) + return 0; + + return DIV_ROUND_UP(cyc, hclk_tns); +} + +/** + * calc_0124 - calculate divisor control for divisors that do /0, /1. /2 and /4 + * @cyc: The cycle time, in 10ths of nanoseconds. + * @hclk_tns: The cycle time for HCLK, in 10ths of nanoseconds. + * @v: Pointer to register to alter. + * @shift: The shift to get to the control bits. + * + * Calculate the divisor, and turn it into the correct control bits to + * set in the result, @v. + */ +static unsigned int calc_0124(unsigned int cyc, unsigned long hclk_tns, + unsigned long *v, int shift) +{ + unsigned int div = to_div(cyc, hclk_tns); + unsigned long val; + + s3c_freq_iodbg("%s: cyc=%d, hclk=%lu, shift=%d => div %d\n", + __func__, cyc, hclk_tns, shift, div); + + switch (div) { + case 0: + val = 0; + break; + case 1: + val = 1; + break; + case 2: + val = 2; + break; + case 3: + case 4: + val = 3; + break; + default: + return -1; + } + + *v |= val << shift; + return 0; +} + +int calc_tacp(unsigned int cyc, unsigned long hclk, unsigned long *v) +{ + /* Currently no support for Tacp calculations. */ + return 0; +} + +/** + * calc_tacc - calculate divisor control for tacc. + * @cyc: The cycle time, in 10ths of nanoseconds. + * @nwait_en: IS nWAIT enabled for this bank. + * @hclk_tns: The cycle time for HCLK, in 10ths of nanoseconds. + * @v: Pointer to register to alter. + * + * Calculate the divisor control for tACC, taking into account whether + * the bank has nWAIT enabled. The result is used to modify the value + * pointed to by @v. +*/ +static int calc_tacc(unsigned int cyc, int nwait_en, + unsigned long hclk_tns, unsigned long *v) +{ + unsigned int div = to_div(cyc, hclk_tns); + unsigned long val; + + s3c_freq_iodbg("%s: cyc=%u, nwait=%d, hclk=%lu => div=%u\n", + __func__, cyc, nwait_en, hclk_tns, div); + + /* if nWait enabled on an bank, Tacc must be at-least 4 cycles. */ + if (nwait_en && div < 4) + div = 4; + + switch (div) { + case 0: + val = 0; + break; + + case 1: + case 2: + case 3: + case 4: + val = div - 1; + break; + + case 5: + case 6: + val = 4; + break; + + case 7: + case 8: + val = 5; + break; + + case 9: + case 10: + val = 6; + break; + + case 11: + case 12: + case 13: + case 14: + val = 7; + break; + + default: + return -1; + } + + *v |= val << 8; + return 0; +} + +/** + * s3c2410_calc_bank - calculate bank timing infromation + * @cfg: The configuration we need to calculate for. + * @bt: The bank timing information. + * + * Given the cycle timine for a bank @bt, calculate the new BANKCON + * setting for the @cfg timing. This updates the timing information + * ready for the cpu frequency change. + */ +static int s3c2410_calc_bank(struct s3c_cpufreq_config *cfg, + struct s3c2410_iobank_timing *bt) +{ + unsigned long hclk = cfg->freq.hclk_tns; + unsigned long res; + int ret; + + res = bt->bankcon; + res &= (S3C2410_BANKCON_SDRAM | S3C2410_BANKCON_PMC16); + + /* tacp: 2,3,4,5 */ + /* tcah: 0,1,2,4 */ + /* tcoh: 0,1,2,4 */ + /* tacc: 1,2,3,4,6,7,10,14 (>4 for nwait) */ + /* tcos: 0,1,2,4 */ + /* tacs: 0,1,2,4 */ + + ret = calc_0124(bt->tacs, hclk, &res, S3C2410_BANKCON_Tacs_SHIFT); + ret |= calc_0124(bt->tcos, hclk, &res, S3C2410_BANKCON_Tcos_SHIFT); + ret |= calc_0124(bt->tcah, hclk, &res, S3C2410_BANKCON_Tcah_SHIFT); + ret |= calc_0124(bt->tcoh, hclk, &res, S3C2410_BANKCON_Tcoh_SHIFT); + + if (ret) + return -EINVAL; + + ret |= calc_tacp(bt->tacp, hclk, &res); + ret |= calc_tacc(bt->tacc, bt->nwait_en, hclk, &res); + + if (ret) + return -EINVAL; + + bt->bankcon = res; + return 0; +} + +static unsigned int tacc_tab[] = { + [0] = 1, + [1] = 2, + [2] = 3, + [3] = 4, + [4] = 6, + [5] = 9, + [6] = 10, + [7] = 14, +}; + +/** + * get_tacc - turn tACC value into cycle time + * @hclk_tns: The cycle time for HCLK, in 10ths of nanoseconds. + * @val: The bank timing register value, shifed down. + */ +static unsigned int get_tacc(unsigned long hclk_tns, + unsigned long val) +{ + val &= 7; + return hclk_tns * tacc_tab[val]; +} + +/** + * get_0124 - turn 0/1/2/4 divider into cycle time + * @hclk_tns: The cycle time for HCLK, in 10ths of nanoseconds. + * @val: The bank timing register value, shifed down. + */ +static unsigned int get_0124(unsigned long hclk_tns, + unsigned long val) +{ + val &= 3; + return hclk_tns * ((val == 3) ? 4 : val); +} + +/** + * s3c2410_iotiming_getbank - turn BANKCON into cycle time information + * @cfg: The frequency configuration + * @bt: The bank timing to fill in (uses cached BANKCON) + * + * Given the BANKCON setting in @bt and the current frequency settings + * in @cfg, update the cycle timing information. + */ +void s3c2410_iotiming_getbank(struct s3c_cpufreq_config *cfg, + struct s3c2410_iobank_timing *bt) +{ + unsigned long bankcon = bt->bankcon; + unsigned long hclk = cfg->freq.hclk_tns; + + bt->tcah = get_0124(hclk, bankcon >> S3C2410_BANKCON_Tcah_SHIFT); + bt->tcoh = get_0124(hclk, bankcon >> S3C2410_BANKCON_Tcoh_SHIFT); + bt->tcos = get_0124(hclk, bankcon >> S3C2410_BANKCON_Tcos_SHIFT); + bt->tacs = get_0124(hclk, bankcon >> S3C2410_BANKCON_Tacs_SHIFT); + bt->tacc = get_tacc(hclk, bankcon >> S3C2410_BANKCON_Tacc_SHIFT); +} + +/** + * s3c2410_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 s3c2410_iotiming_debugfs(struct seq_file *seq, + struct s3c_cpufreq_config *cfg, + union s3c_iobank *iob) +{ + struct s3c2410_iobank_timing *bt = iob->io_2410; + unsigned long bankcon = bt->bankcon; + unsigned long hclk = cfg->freq.hclk_tns; + unsigned int tacs; + unsigned int tcos; + unsigned int tacc; + unsigned int tcoh; + unsigned int tcah; + + seq_printf(seq, "BANKCON=0x%08lx\n", bankcon); + + tcah = get_0124(hclk, bankcon >> S3C2410_BANKCON_Tcah_SHIFT); + tcoh = get_0124(hclk, bankcon >> S3C2410_BANKCON_Tcoh_SHIFT); + tcos = get_0124(hclk, bankcon >> S3C2410_BANKCON_Tcos_SHIFT); + tacs = get_0124(hclk, bankcon >> S3C2410_BANKCON_Tacs_SHIFT); + tacc = get_tacc(hclk, bankcon >> S3C2410_BANKCON_Tacc_SHIFT); + + seq_printf(seq, + "\tRead: Tacs=%d.%d, Tcos=%d.%d, Tacc=%d.%d, Tcoh=%d.%d, Tcah=%d.%d\n", + print_ns(bt->tacs), + print_ns(bt->tcos), + print_ns(bt->tacc), + print_ns(bt->tcoh), + print_ns(bt->tcah)); + + seq_printf(seq, + "\t Set: Tacs=%d.%d, Tcos=%d.%d, Tacc=%d.%d, Tcoh=%d.%d, Tcah=%d.%d\n", + print_ns(tacs), + print_ns(tcos), + print_ns(tacc), + print_ns(tcoh), + print_ns(tcah)); +} + +/** + * s3c2410_iotiming_calc - Calculate bank timing for frequency change. + * @cfg: The frequency configuration + * @iot: The IO timing information to fill out. + * + * Calculate the new values for the banks in @iot based on the new + * frequency information in @cfg. This is then used by s3c2410_iotiming_set() + * to update the timing when necessary. + */ +int s3c2410_iotiming_calc(struct s3c_cpufreq_config *cfg, + struct s3c_iotimings *iot) +{ + struct s3c2410_iobank_timing *bt; + unsigned long bankcon; + int bank; + int ret; + + for (bank = 0; bank < MAX_BANKS; bank++) { + bankcon = __raw_readl(bank_reg(bank)); + bt = iot->bank[bank].io_2410; + + if (!bt) + continue; + + bt->bankcon = bankcon; + + ret = s3c2410_calc_bank(cfg, bt); + if (ret) { + printk(KERN_ERR "%s: cannot calculate bank %d io\n", + __func__, bank); + goto err; + } + + s3c_freq_iodbg("%s: bank %d: con=%08lx\n", + __func__, bank, bt->bankcon); + } + + return 0; + err: + return ret; +} + +/** + * s3c2410_iotiming_set - set the IO timings from the given setup. + * @cfg: The frequency configuration + * @iot: The IO timing information to use. + * + * Set all the currently used IO bank timing information generated + * by s3c2410_iotiming_calc() once the core has validated that all + * the new values are within permitted bounds. + */ +void s3c2410_iotiming_set(struct s3c_cpufreq_config *cfg, + struct s3c_iotimings *iot) +{ + struct s3c2410_iobank_timing *bt; + int bank; + + /* set the io timings from the specifier */ + + for (bank = 0; bank < MAX_BANKS; bank++) { + bt = iot->bank[bank].io_2410; + if (!bt) + continue; + + __raw_writel(bt->bankcon, bank_reg(bank)); + } +} + +/** + * s3c2410_iotiming_get - Get the timing information from current registers. + * @cfg: The frequency configuration + * @timings: The IO timing information to fill out. + * + * Calculate the @timings timing information from the current frequency + * information in @cfg, and the new frequency configur + * through all the IO banks, reading the state and then updating @iot + * as necessary. + * + * This is used at the moment on initialisation to get the current + * configuration so that boards do not have to carry their own setup + * if the timings are correct on initialisation. + */ + +int s3c2410_iotiming_get(struct s3c_cpufreq_config *cfg, + struct s3c_iotimings *timings) +{ + struct s3c2410_iobank_timing *bt; + unsigned long bankcon; + unsigned long bwscon; + int bank; + + bwscon = __raw_readl(S3C2410_BWSCON); + + /* look through all banks to see what is currently set. */ + + for (bank = 0; bank < MAX_BANKS; bank++) { + bankcon = __raw_readl(bank_reg(bank)); + + if (!bank_is_io(bankcon)) + continue; + + s3c_freq_iodbg("%s: bank %d: con %08lx\n", + __func__, bank, bankcon); + + bt = kzalloc(sizeof(struct s3c2410_iobank_timing), GFP_KERNEL); + if (!bt) { + printk(KERN_ERR "%s: no memory for bank\n", __func__); + return -ENOMEM; + } + + /* find out in nWait is enabled for bank. */ + + if (bank != 0) { + unsigned long tmp = S3C2410_BWSCON_GET(bwscon, bank); + if (tmp & S3C2410_BWSCON_WS) + bt->nwait_en = 1; + } + + timings->bank[bank].io_2410 = bt; + bt->bankcon = bankcon; + + s3c2410_iotiming_getbank(cfg, bt); + } + + s3c2410_print_timing("get", timings); + return 0; +} |