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sdrc2xxx.c

/*
 * linux/arch/arm/mach-omap2/sdrc2xxx.c
 *
 * SDRAM timing related functions for OMAP2xxx
 *
 * Copyright (C) 2005, 2008 Texas Instruments Inc.
 * Copyright (C) 2005, 2008 Nokia Corporation
 *
 * Tony Lindgren <tony@atomide.com>
 * Paul Walmsley
 * Richard Woodruff <r-woodruff2@ti.com>
 *
 * 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/module.h>
#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/list.h>
#include <linux/errno.h>
#include <linux/delay.h>
#include <linux/clk.h>
#include <linux/io.h>

#include <plat/common.h>
#include <plat/clock.h>
#include <plat/sram.h>

#include "prm2xxx_3xxx.h"
#include "clock.h"
#include <plat/sdrc.h>
#include "sdrc.h"

/* Memory timing, DLL mode flags */
#define M_DDR           1
#define M_LOCK_CTRL     (1 << 2)
#define M_UNLOCK  0
#define M_LOCK          1


static struct memory_timings mem_timings;
static u32 curr_perf_level = CORE_CLK_SRC_DPLL_X2;

static u32 omap2xxx_sdrc_get_slow_dll_ctrl(void)
{
      return mem_timings.slow_dll_ctrl;
}

static u32 omap2xxx_sdrc_get_fast_dll_ctrl(void)
{
      return mem_timings.fast_dll_ctrl;
}

static u32 omap2xxx_sdrc_get_type(void)
{
      return mem_timings.m_type;
}

/*
 * Check the DLL lock state, and return tue if running in unlock mode.
 * This is needed to compensate for the shifted DLL value in unlock mode.
 */
u32 omap2xxx_sdrc_dll_is_unlocked(void)
{
      /* dlla and dllb are a set */
      u32 dll_state = sdrc_read_reg(SDRC_DLLA_CTRL);

      if ((dll_state & (1 << 2)) == (1 << 2))
            return 1;
      else
            return 0;
}

/*
 * 'level' is the value to store to CM_CLKSEL2_PLL.CORE_CLK_SRC.
 * Practical values are CORE_CLK_SRC_DPLL (for CORE_CLK = DPLL_CLK) or
 * CORE_CLK_SRC_DPLL_X2 (for CORE_CLK = * DPLL_CLK * 2)
 *
 * Used by the clock framework during CORE DPLL changes
 */
u32 omap2xxx_sdrc_reprogram(u32 level, u32 force)
{
      u32 dll_ctrl, m_type;
      u32 prev = curr_perf_level;
      unsigned long flags;

      if ((curr_perf_level == level) && !force)
            return prev;

      if (level == CORE_CLK_SRC_DPLL)
            dll_ctrl = omap2xxx_sdrc_get_slow_dll_ctrl();
      else if (level == CORE_CLK_SRC_DPLL_X2)
            dll_ctrl = omap2xxx_sdrc_get_fast_dll_ctrl();
      else
            return prev;

      m_type = omap2xxx_sdrc_get_type();

      local_irq_save(flags);
      /*
       * XXX These calls should be abstracted out through a
       * prm2xxx.c function
       */
      if (cpu_is_omap2420())
            __raw_writel(0xffff, OMAP2420_PRCM_VOLTSETUP);
      else
            __raw_writel(0xffff, OMAP2430_PRCM_VOLTSETUP);
      omap2_sram_reprogram_sdrc(level, dll_ctrl, m_type);
      curr_perf_level = level;
      local_irq_restore(flags);

      return prev;
}

/* Used by the clock framework during CORE DPLL changes */
void omap2xxx_sdrc_init_params(u32 force_lock_to_unlock_mode)
{
      unsigned long dll_cnt;
      u32 fast_dll = 0;

      /* DDR = 1, SDR = 0 */
      mem_timings.m_type = !((sdrc_read_reg(SDRC_MR_0) & 0x3) == 0x1);

      /* 2422 es2.05 and beyond has a single SIP DDR instead of 2 like others.
       * In the case of 2422, its ok to use CS1 instead of CS0.
       */
      if (cpu_is_omap2422())
            mem_timings.base_cs = 1;
      else
            mem_timings.base_cs = 0;

      if (mem_timings.m_type != M_DDR)
            return;

      /* With DDR we need to determine the low frequency DLL value */
      if (((mem_timings.fast_dll_ctrl & (1 << 2)) == M_LOCK_CTRL))
            mem_timings.dll_mode = M_UNLOCK;
      else
            mem_timings.dll_mode = M_LOCK;

      if (mem_timings.base_cs == 0) {
            fast_dll = sdrc_read_reg(SDRC_DLLA_CTRL);
            dll_cnt = sdrc_read_reg(SDRC_DLLA_STATUS) & 0xff00;
      } else {
            fast_dll = sdrc_read_reg(SDRC_DLLB_CTRL);
            dll_cnt = sdrc_read_reg(SDRC_DLLB_STATUS) & 0xff00;
      }
      if (force_lock_to_unlock_mode) {
            fast_dll &= ~0xff00;
            fast_dll |= dll_cnt;          /* Current lock mode */
      }
      /* set fast timings with DLL filter disabled */
      mem_timings.fast_dll_ctrl = (fast_dll | (3 << 8));

      /* No disruptions, DDR will be offline & C-ABI not followed */
      omap2_sram_ddr_init(&mem_timings.slow_dll_ctrl,
                      mem_timings.fast_dll_ctrl,
                      mem_timings.base_cs,
                      force_lock_to_unlock_mode);
      mem_timings.slow_dll_ctrl &= 0xff00;      /* Keep lock value */

      /* Turn status into unlock ctrl */
      mem_timings.slow_dll_ctrl |=
            ((mem_timings.fast_dll_ctrl & 0xF) | (1 << 2));

      /* 90 degree phase for anything below 133Mhz + disable DLL filter */
      mem_timings.slow_dll_ctrl |= ((1 << 1) | (3 << 8));
}

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