arch/arm/plat-s3c24xx/s3c2410-iotiming.c - kernel/skids - Git at Google

 /* 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;
 }
	/* 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;
	}