arch/arm/mach-omap2/sdrc.c

   1 /*
   2  * SMS/SDRC (SDRAM controller) common code for OMAP2/3
   3  *
   4  * Copyright (C) 2005, 2008 Texas Instruments Inc.
   5  * Copyright (C) 2005, 2008 Nokia Corporation
   6  *
   7  * Tony Lindgren <tony@atomide.com>
   8  * Paul Walmsley
   9  * Richard Woodruff <r-woodruff2@ti.com>
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License version 2 as
  13  * published by the Free Software Foundation.
  14  */
  15 #undef DEBUG
  16
  17 #include <linux/module.h>
  18 #include <linux/kernel.h>
  19 #include <linux/device.h>
  20 #include <linux/list.h>
  21 #include <linux/errno.h>
  22 #include <linux/delay.h>
  23 #include <linux/clk.h>
  24 #include <linux/io.h>
  25
  26 #include <plat/common.h>
  27 #include <plat/clock.h>
  28 #include <plat/sram.h>
  29
  30 #include "prm.h"
  31
  32 #include <plat/sdrc.h>
  33 #include "sdrc.h"
  34
  35 static struct omap_sdrc_params *sdrc_init_params_cs0, *sdrc_init_params_cs1;
  36
  37 void __iomem *omap2_sdrc_base;
  38 void __iomem *omap2_sms_base;
  39
  40 struct omap2_sms_regs {
  41         u32     sms_sysconfig;
  42 };
  43
  44 static struct omap2_sms_regs sms_context;
  45
  46 /* SDRC_POWER register bits */
  47 #define SDRC_POWER_EXTCLKDIS_SHIFT              3
  48 #define SDRC_POWER_PWDENA_SHIFT                 2
  49 #define SDRC_POWER_PAGEPOLICY_SHIFT             0
  50
  51 /**
  52  * omap2_sms_save_context - Save SMS registers
  53  *
  54  * Save SMS registers that need to be restored after off mode.
  55  */
  56 void omap2_sms_save_context(void)
  57 {
  58         sms_context.sms_sysconfig = sms_read_reg(SMS_SYSCONFIG);
  59 }
  60
  61 /**
  62  * omap2_sms_restore_context - Restore SMS registers
  63  *
  64  * Restore SMS registers that need to be Restored after off mode.
  65  */
  66 void omap2_sms_restore_context(void)
  67 {
  68         sms_write_reg(sms_context.sms_sysconfig, SMS_SYSCONFIG);
  69 }
  70
  71 /**
  72  * omap2_sdrc_get_params - return SDRC register values for a given clock rate
  73  * @r: SDRC clock rate (in Hz)
  74  * @sdrc_cs0: chip select 0 ram timings **
  75  * @sdrc_cs1: chip select 1 ram timings **
  76  *
  77  * Return pre-calculated values for the SDRC_ACTIM_CTRLA,
  78  *  SDRC_ACTIM_CTRLB, SDRC_RFR_CTRL and SDRC_MR registers in sdrc_cs[01]
  79  *  structs,for a given SDRC clock rate 'r'.
  80  * These parameters control various timing delays in the SDRAM controller
  81  *  that are expressed in terms of the number of SDRC clock cycles to
  82  *  wait; hence the clock rate dependency.
  83  *
  84  * Supports 2 different timing parameters for both chip selects.
  85  *
  86  * Note 1: the sdrc_init_params_cs[01] must be sorted rate descending.
  87  * Note 2: If sdrc_init_params_cs_1 is not NULL it must be of same size
  88  *  as sdrc_init_params_cs_0.
  89  *
  90  * Fills in the struct omap_sdrc_params * for each chip select.
  91  * Returns 0 upon success or -1 upon failure.
  92  */
  93 int omap2_sdrc_get_params(unsigned long r,
  94                           struct omap_sdrc_params **sdrc_cs0,
  95                           struct omap_sdrc_params **sdrc_cs1)
  96 {
  97         struct omap_sdrc_params *sp0, *sp1;
  98
  99         if (!sdrc_init_params_cs0)
 100                 return -1;
 101
 102         sp0 = sdrc_init_params_cs0;
 103         sp1 = sdrc_init_params_cs1;
 104
 105         while (sp0->rate && sp0->rate != r) {
 106                 sp0++;
 107                 if (sdrc_init_params_cs1)
 108                         sp1++;
 109         }
 110
 111         if (!sp0->rate)
 112                 return -1;
 113
 114         *sdrc_cs0 = sp0;
 115         *sdrc_cs1 = sp1;
 116         return 0;
 117 }
 118
 119
 120 void __init omap2_set_globals_sdrc(struct omap_globals *omap2_globals)
 121 {
 122         omap2_sdrc_base = omap2_globals->sdrc;
 123         omap2_sms_base = omap2_globals->sms;
 124 }
 125
 126 /**
 127  * omap2_sdrc_init - initialize SMS, SDRC devices on boot
 128  * @sdrc_cs[01]: pointers to a null-terminated list of struct omap_sdrc_params
 129  *  Support for 2 chip selects timings
 130  *
 131  * Turn on smart idle modes for SDRAM scheduler and controller.
 132  * Program a known-good configuration for the SDRC to deal with buggy
 133  * bootloaders.
 134  */
 135 void __init omap2_sdrc_init(struct omap_sdrc_params *sdrc_cs0,
 136                             struct omap_sdrc_params *sdrc_cs1)
 137 {
 138         u32 l;
 139
 140         l = sms_read_reg(SMS_SYSCONFIG);
 141         l &= ~(0x3 << 3);
 142         l |= (0x2 << 3);
 143         sms_write_reg(l, SMS_SYSCONFIG);
 144
 145         l = sdrc_read_reg(SDRC_SYSCONFIG);
 146         l &= ~(0x3 << 3);
 147         l |= (0x2 << 3);
 148         sdrc_write_reg(l, SDRC_SYSCONFIG);
 149
 150         sdrc_init_params_cs0 = sdrc_cs0;
 151         sdrc_init_params_cs1 = sdrc_cs1;
 152
 153         /* XXX Enable SRFRONIDLEREQ here also? */
 154         /*
 155          * PWDENA should not be set due to 34xx erratum 1.150 - PWDENA
 156          * can cause random memory corruption
 157          */
 158         l = (1 << SDRC_POWER_EXTCLKDIS_SHIFT) |
 159                 (1 << SDRC_POWER_PAGEPOLICY_SHIFT);
 160         sdrc_write_reg(l, SDRC_POWER);
 161         omap2_sms_save_context();
 162 }