arch/arm/mach-omap2/sdrc2xxx.c

   1 /*
   2  * linux/arch/arm/mach-omap2/sdrc2xxx.c
   3  *
   4  * SDRAM timing related functions for OMAP2xxx
   5  *
   6  * Copyright (C) 2005, 2008 Texas Instruments Inc.
   7  * Copyright (C) 2005, 2008 Nokia Corporation
   8  *
   9  * Tony Lindgren <tony@atomide.com>
  10  * Paul Walmsley
  11  * Richard Woodruff <r-woodruff2@ti.com>
  12  *
  13  * This program is free software; you can redistribute it and/or modify
  14  * it under the terms of the GNU General Public License version 2 as
  15  * published by the Free Software Foundation.
  16  */
  17
  18 #include <linux/module.h>
  19 #include <linux/kernel.h>
  20 #include <linux/device.h>
  21 #include <linux/list.h>
  22 #include <linux/errno.h>
  23 #include <linux/delay.h>
  24 #include <linux/clk.h>
  25 #include <linux/io.h>
  26
  27 #include "soc.h"
  28 #include "iomap.h"
  29 #include "common.h"
  30 #include "prm2xxx.h"
  31 #include "clock.h"
  32 #include "sdrc.h"
  33 #include "sram.h"
  34
  35 /* Memory timing, DLL mode flags */
  36 #define M_DDR           1
  37 #define M_LOCK_CTRL     (1 << 2)
  38 #define M_UNLOCK        0
  39 #define M_LOCK          1
  40
  41
  42 static struct memory_timings mem_timings;
  43 static u32 curr_perf_level = CORE_CLK_SRC_DPLL_X2;
  44
  45 static u32 omap2xxx_sdrc_get_slow_dll_ctrl(void)
  46 {
  47         return mem_timings.slow_dll_ctrl;
  48 }
  49
  50 static u32 omap2xxx_sdrc_get_fast_dll_ctrl(void)
  51 {
  52         return mem_timings.fast_dll_ctrl;
  53 }
  54
  55 static u32 omap2xxx_sdrc_get_type(void)
  56 {
  57         return mem_timings.m_type;
  58 }
  59
  60 /*
  61  * Check the DLL lock state, and return tue if running in unlock mode.
  62  * This is needed to compensate for the shifted DLL value in unlock mode.
  63  */
  64 u32 omap2xxx_sdrc_dll_is_unlocked(void)
  65 {
  66         /* dlla and dllb are a set */
  67         u32 dll_state = sdrc_read_reg(SDRC_DLLA_CTRL);
  68
  69         if ((dll_state & (1 << 2)) == (1 << 2))
  70                 return 1;
  71         else
  72                 return 0;
  73 }
  74
  75 /*
  76  * 'level' is the value to store to CM_CLKSEL2_PLL.CORE_CLK_SRC.
  77  * Practical values are CORE_CLK_SRC_DPLL (for CORE_CLK = DPLL_CLK) or
  78  * CORE_CLK_SRC_DPLL_X2 (for CORE_CLK = * DPLL_CLK * 2)
  79  *
  80  * Used by the clock framework during CORE DPLL changes
  81  */
  82 u32 omap2xxx_sdrc_reprogram(u32 level, u32 force)
  83 {
  84         u32 dll_ctrl, m_type;
  85         u32 prev = curr_perf_level;
  86         unsigned long flags;
  87
  88         if ((curr_perf_level == level) && !force)
  89                 return prev;
  90
  91         if (level == CORE_CLK_SRC_DPLL)
  92                 dll_ctrl = omap2xxx_sdrc_get_slow_dll_ctrl();
  93         else if (level == CORE_CLK_SRC_DPLL_X2)
  94                 dll_ctrl = omap2xxx_sdrc_get_fast_dll_ctrl();
  95         else
  96                 return prev;
  97
  98         m_type = omap2xxx_sdrc_get_type();
  99
 100         local_irq_save(flags);
 101         /*
 102          * XXX These calls should be abstracted out through a
 103          * prm2xxx.c function
 104          */
 105         if (cpu_is_omap2420())
 106                 writel_relaxed(0xffff, OMAP2420_PRCM_VOLTSETUP);
 107         else
 108                 writel_relaxed(0xffff, OMAP2430_PRCM_VOLTSETUP);
 109         omap2_sram_reprogram_sdrc(level, dll_ctrl, m_type);
 110         curr_perf_level = level;
 111         local_irq_restore(flags);
 112
 113         return prev;
 114 }
 115
 116 /* Used by the clock framework during CORE DPLL changes */
 117 void omap2xxx_sdrc_init_params(u32 force_lock_to_unlock_mode)
 118 {
 119         unsigned long dll_cnt;
 120         u32 fast_dll = 0;
 121
 122         /* DDR = 1, SDR = 0 */
 123         mem_timings.m_type = !((sdrc_read_reg(SDRC_MR_0) & 0x3) == 0x1);
 124
 125         /* 2422 es2.05 and beyond has a single SIP DDR instead of 2 like others.
 126          * In the case of 2422, its ok to use CS1 instead of CS0.
 127          */
 128         if (cpu_is_omap2422())
 129                 mem_timings.base_cs = 1;
 130         else
 131                 mem_timings.base_cs = 0;
 132
 133         if (mem_timings.m_type != M_DDR)
 134                 return;
 135
 136         /* With DDR we need to determine the low frequency DLL value */
 137         if (((mem_timings.fast_dll_ctrl & (1 << 2)) == M_LOCK_CTRL))
 138                 mem_timings.dll_mode = M_UNLOCK;
 139         else
 140                 mem_timings.dll_mode = M_LOCK;
 141
 142         if (mem_timings.base_cs == 0) {
 143                 fast_dll = sdrc_read_reg(SDRC_DLLA_CTRL);
 144                 dll_cnt = sdrc_read_reg(SDRC_DLLA_STATUS) & 0xff00;
 145         } else {
 146                 fast_dll = sdrc_read_reg(SDRC_DLLB_CTRL);
 147                 dll_cnt = sdrc_read_reg(SDRC_DLLB_STATUS) & 0xff00;
 148         }
 149         if (force_lock_to_unlock_mode) {
 150                 fast_dll &= ~0xff00;
 151                 fast_dll |= dll_cnt;            /* Current lock mode */
 152         }
 153         /* set fast timings with DLL filter disabled */
 154         mem_timings.fast_dll_ctrl = (fast_dll | (3 << 8));
 155
 156         /* No disruptions, DDR will be offline & C-ABI not followed */
 157         omap2_sram_ddr_init(&mem_timings.slow_dll_ctrl,
 158                             mem_timings.fast_dll_ctrl,
 159                             mem_timings.base_cs,
 160                             force_lock_to_unlock_mode);
 161         mem_timings.slow_dll_ctrl &= 0xff00;    /* Keep lock value */
 162
 163         /* Turn status into unlock ctrl */
 164         mem_timings.slow_dll_ctrl |=
 165                 ((mem_timings.fast_dll_ctrl & 0xF) | (1 << 2));
 166
 167         /* 90 degree phase for anything below 133Mhz + disable DLL filter */
 168         mem_timings.slow_dll_ctrl |= ((1 << 1) | (3 << 8));
 169 }