/* linux/arch/arm/plat-s3c24xx/s3c2410-iotiming.c
*
* Copyright (c) 2006-2009 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 <linux/slab.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;
}
