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