arch/arm/mach-s3c24xx/iotiming-s3c2412.c

   1 /*
   2  * Copyright (c) 2006-2008 Simtec Electronics
   3  *      http://armlinux.simtec.co.uk/
   4  *      Ben Dooks <ben@simtec.co.uk>
   5  *
   6  * S3C2412/S3C2443 (PL093 based) IO timing support
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11 */
  12
  13 #include <linux/init.h>
  14 #include <linux/module.h>
  15 #include <linux/interrupt.h>
  16 #include <linux/ioport.h>
  17 #include <linux/cpufreq.h>
  18 #include <linux/seq_file.h>
  19 #include <linux/device.h>
  20 #include <linux/delay.h>
  21 #include <linux/clk.h>
  22 #include <linux/err.h>
  23 #include <linux/slab.h>
  24
  25 #include <linux/amba/pl093.h>
  26
  27 #include <asm/mach/arch.h>
  28 #include <asm/mach/map.h>
  29
  30 #include <plat/cpu.h>
  31 #include <plat/cpu-freq-core.h>
  32 #include <plat/clock.h>
  33
  34 #include "s3c2412.h"
  35
  36 #define print_ns(x) ((x) / 10), ((x) % 10)
  37
  38 /**
  39  * s3c2412_print_timing - print timing infromation via printk.
  40  * @pfx: The prefix to print each line with.
  41  * @iot: The IO timing information
  42  */
  43 static void s3c2412_print_timing(const char *pfx, struct s3c_iotimings *iot)
  44 {
  45         struct s3c2412_iobank_timing *bt;
  46         unsigned int bank;
  47
  48         for (bank = 0; bank < MAX_BANKS; bank++) {
  49                 bt = iot->bank[bank].io_2412;
  50                 if (!bt)
  51                         continue;
  52
  53                 printk(KERN_DEBUG "%s: %d: idcy=%d.%d wstrd=%d.%d wstwr=%d,%d"
  54                        "wstoen=%d.%d wstwen=%d.%d wstbrd=%d.%d\n", pfx, bank,
  55                        print_ns(bt->idcy),
  56                        print_ns(bt->wstrd),
  57                        print_ns(bt->wstwr),
  58                        print_ns(bt->wstoen),
  59                        print_ns(bt->wstwen),
  60                        print_ns(bt->wstbrd));
  61         }
  62 }
  63
  64 /**
  65  * to_div - turn a cycle length into a divisor setting.
  66  * @cyc_tns: The cycle time in 10ths of nanoseconds.
  67  * @clk_tns: The clock period in 10ths of nanoseconds.
  68  */
  69 static inline unsigned int to_div(unsigned int cyc_tns, unsigned int clk_tns)
  70 {
  71         return cyc_tns ? DIV_ROUND_UP(cyc_tns, clk_tns) : 0;
  72 }
  73
  74 /**
  75  * calc_timing - calculate timing divisor value and check in range.
  76  * @hwtm: The hardware timing in 10ths of nanoseconds.
  77  * @clk_tns: The clock period in 10ths of nanoseconds.
  78  * @err: Pointer to err variable to update in event of failure.
  79  */
  80 static unsigned int calc_timing(unsigned int hwtm, unsigned int clk_tns,
  81                                 unsigned int *err)
  82 {
  83         unsigned int ret = to_div(hwtm, clk_tns);
  84
  85         if (ret > 0xf)
  86                 *err = -EINVAL;
  87
  88         return ret;
  89 }
  90
  91 /**
  92  * s3c2412_calc_bank - calculate the bank divisor settings.
  93  * @cfg: The current frequency configuration.
  94  * @bt: The bank timing.
  95  */
  96 static int s3c2412_calc_bank(struct s3c_cpufreq_config *cfg,
  97                              struct s3c2412_iobank_timing *bt)
  98 {
  99         unsigned int hclk = cfg->freq.hclk_tns;
 100         int err = 0;
 101
 102         bt->smbidcyr = calc_timing(bt->idcy, hclk, &err);
 103         bt->smbwstrd = calc_timing(bt->wstrd, hclk, &err);
 104         bt->smbwstwr = calc_timing(bt->wstwr, hclk, &err);
 105         bt->smbwstoen = calc_timing(bt->wstoen, hclk, &err);
 106         bt->smbwstwen = calc_timing(bt->wstwen, hclk, &err);
 107         bt->smbwstbrd = calc_timing(bt->wstbrd, hclk, &err);
 108
 109         return err;
 110 }
 111
 112 /**
 113  * s3c2412_iotiming_debugfs - debugfs show io bank timing information
 114  * @seq: The seq_file to write output to using seq_printf().
 115  * @cfg: The current configuration.
 116  * @iob: The IO bank information to decode.
 117 */
 118 void s3c2412_iotiming_debugfs(struct seq_file *seq,
 119                               struct s3c_cpufreq_config *cfg,
 120                               union s3c_iobank *iob)
 121 {
 122         struct s3c2412_iobank_timing *bt = iob->io_2412;
 123
 124         seq_printf(seq,
 125                    "\tRead: idcy=%d.%d wstrd=%d.%d wstwr=%d,%d"
 126                    "wstoen=%d.%d wstwen=%d.%d wstbrd=%d.%d\n",
 127                    print_ns(bt->idcy),
 128                    print_ns(bt->wstrd),
 129                    print_ns(bt->wstwr),
 130                    print_ns(bt->wstoen),
 131                    print_ns(bt->wstwen),
 132                    print_ns(bt->wstbrd));
 133 }
 134
 135 /**
 136  * s3c2412_iotiming_calc - calculate all the bank divisor settings.
 137  * @cfg: The current frequency configuration.
 138  * @iot: The bank timing information.
 139  *
 140  * Calculate the timing information for all the banks that are
 141  * configured as IO, using s3c2412_calc_bank().
 142  */
 143 int s3c2412_iotiming_calc(struct s3c_cpufreq_config *cfg,
 144                           struct s3c_iotimings *iot)
 145 {
 146         struct s3c2412_iobank_timing *bt;
 147         int bank;
 148         int ret;
 149
 150         for (bank = 0; bank < MAX_BANKS; bank++) {
 151                 bt = iot->bank[bank].io_2412;
 152                 if (!bt)
 153                         continue;
 154
 155                 ret = s3c2412_calc_bank(cfg, bt);
 156                 if (ret) {
 157                         printk(KERN_ERR "%s: cannot calculate bank %d io\n",
 158                                __func__, bank);
 159                         goto err;
 160                 }
 161         }
 162
 163         return 0;
 164  err:
 165         return ret;
 166 }
 167
 168 /**
 169  * s3c2412_iotiming_set - set the timing information
 170  * @cfg: The current frequency configuration.
 171  * @iot: The bank timing information.
 172  *
 173  * Set the IO bank information from the details calculated earlier from
 174  * calling s3c2412_iotiming_calc().
 175  */
 176 void s3c2412_iotiming_set(struct s3c_cpufreq_config *cfg,
 177                           struct s3c_iotimings *iot)
 178 {
 179         struct s3c2412_iobank_timing *bt;
 180         void __iomem *regs;
 181         int bank;
 182
 183         /* set the io timings from the specifier */
 184
 185         for (bank = 0; bank < MAX_BANKS; bank++) {
 186                 bt = iot->bank[bank].io_2412;
 187                 if (!bt)
 188                         continue;
 189
 190                 regs = S3C2412_SSMC_BANK(bank);
 191
 192                 __raw_writel(bt->smbidcyr, regs + SMBIDCYR);
 193                 __raw_writel(bt->smbwstrd, regs + SMBWSTRDR);
 194                 __raw_writel(bt->smbwstwr, regs + SMBWSTWRR);
 195                 __raw_writel(bt->smbwstoen, regs + SMBWSTOENR);
 196                 __raw_writel(bt->smbwstwen, regs + SMBWSTWENR);
 197                 __raw_writel(bt->smbwstbrd, regs + SMBWSTBRDR);
 198         }
 199 }
 200
 201 static inline unsigned int s3c2412_decode_timing(unsigned int clock, u32 reg)
 202 {
 203         return (reg & 0xf) * clock;
 204 }
 205
 206 static void s3c2412_iotiming_getbank(struct s3c_cpufreq_config *cfg,
 207                                      struct s3c2412_iobank_timing *bt,
 208                                      unsigned int bank)
 209 {
 210         unsigned long clk = cfg->freq.hclk_tns;  /* ssmc clock??? */
 211         void __iomem *regs = S3C2412_SSMC_BANK(bank);
 212
 213         bt->idcy = s3c2412_decode_timing(clk, __raw_readl(regs + SMBIDCYR));
 214         bt->wstrd = s3c2412_decode_timing(clk, __raw_readl(regs + SMBWSTRDR));
 215         bt->wstoen = s3c2412_decode_timing(clk, __raw_readl(regs + SMBWSTOENR));
 216         bt->wstwen = s3c2412_decode_timing(clk, __raw_readl(regs + SMBWSTWENR));
 217         bt->wstbrd = s3c2412_decode_timing(clk, __raw_readl(regs + SMBWSTBRDR));
 218 }
 219
 220 /**
 221  * bank_is_io - return true if bank is (possibly) IO.
 222  * @bank: The bank number.
 223  * @bankcfg: The value of S3C2412_EBI_BANKCFG.
 224  */
 225 static inline bool bank_is_io(unsigned int bank, u32 bankcfg)
 226 {
 227         if (bank < 2)
 228                 return true;
 229
 230         return !(bankcfg & (1 << bank));
 231 }
 232
 233 int s3c2412_iotiming_get(struct s3c_cpufreq_config *cfg,
 234                          struct s3c_iotimings *timings)
 235 {
 236         struct s3c2412_iobank_timing *bt;
 237         u32 bankcfg = __raw_readl(S3C2412_EBI_BANKCFG);
 238         unsigned int bank;
 239
 240         /* look through all banks to see what is currently set. */
 241
 242         for (bank = 0; bank < MAX_BANKS; bank++) {
 243                 if (!bank_is_io(bank, bankcfg))
 244                         continue;
 245
 246                 bt = kzalloc(sizeof(struct s3c2412_iobank_timing), GFP_KERNEL);
 247                 if (!bt) {
 248                         printk(KERN_ERR "%s: no memory for bank\n", __func__);
 249                         return -ENOMEM;
 250                 }
 251
 252                 timings->bank[bank].io_2412 = bt;
 253                 s3c2412_iotiming_getbank(cfg, bt, bank);
 254         }
 255
 256         s3c2412_print_timing("get", timings);
 257         return 0;
 258 }
 259
 260 /* this is in here as it is so small, it doesn't currently warrant a file
 261  * to itself. We expect that any s3c24xx needing this is going to also
 262  * need the iotiming support.
 263  */
 264 void s3c2412_cpufreq_setrefresh(struct s3c_cpufreq_config *cfg)
 265 {
 266         struct s3c_cpufreq_board *board = cfg->board;
 267         u32 refresh;
 268
 269         WARN_ON(board == NULL);
 270
 271         /* Reduce both the refresh time (in ns) and the frequency (in MHz)
 272          * down to ensure that we do not overflow 32 bit numbers.
 273          *
 274          * This should work for HCLK up to 133MHz and refresh period up
 275          * to 30usec.
 276          */
 277
 278         refresh = (cfg->freq.hclk / 100) * (board->refresh / 10);
 279         refresh = DIV_ROUND_UP(refresh, (1000 * 1000)); /* apply scale  */
 280         refresh &= ((1 << 16) - 1);
 281
 282         s3c_freq_dbg("%s: refresh value %u\n", __func__, (unsigned int)refresh);
 283
 284         __raw_writel(refresh, S3C2412_REFRESH);
 285 }