forked from Minki/linux
75f251e3d0
Stop setting SDRC_POWER.PWDENA on boot. There is a nasty erratum (34xx erratum 1.150) that can cause memory corruption if PWDENA is enabled. Based originally on a patch from Samu P. Onkalo <samu.p.onkalo@nokia.com>. Tested on BeagleBoard rev C2. Signed-off-by: Paul Walmsley <paul@pwsan.com> Cc: Samu P. Onkalo <samu.p.onkalo@nokia.com>
136 lines
3.5 KiB
C
136 lines
3.5 KiB
C
/*
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* SMS/SDRC (SDRAM controller) common code for OMAP2/3
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*
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* Copyright (C) 2005, 2008 Texas Instruments Inc.
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* Copyright (C) 2005, 2008 Nokia Corporation
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*
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* Tony Lindgren <tony@atomide.com>
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* Paul Walmsley
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* Richard Woodruff <r-woodruff2@ti.com>
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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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#undef DEBUG
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/device.h>
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#include <linux/list.h>
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#include <linux/errno.h>
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#include <linux/delay.h>
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#include <linux/clk.h>
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#include <linux/io.h>
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#include <mach/common.h>
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#include <mach/clock.h>
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#include <mach/sram.h>
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#include "prm.h"
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#include <mach/sdrc.h>
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#include "sdrc.h"
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static struct omap_sdrc_params *sdrc_init_params_cs0, *sdrc_init_params_cs1;
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void __iomem *omap2_sdrc_base;
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void __iomem *omap2_sms_base;
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/* SDRC_POWER register bits */
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#define SDRC_POWER_EXTCLKDIS_SHIFT 3
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#define SDRC_POWER_PWDENA_SHIFT 2
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#define SDRC_POWER_PAGEPOLICY_SHIFT 0
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/**
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* omap2_sdrc_get_params - return SDRC register values for a given clock rate
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* @r: SDRC clock rate (in Hz)
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* @sdrc_cs0: chip select 0 ram timings **
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* @sdrc_cs1: chip select 1 ram timings **
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*
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* Return pre-calculated values for the SDRC_ACTIM_CTRLA,
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* SDRC_ACTIM_CTRLB, SDRC_RFR_CTRL and SDRC_MR registers in sdrc_cs[01]
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* structs,for a given SDRC clock rate 'r'.
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* These parameters control various timing delays in the SDRAM controller
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* that are expressed in terms of the number of SDRC clock cycles to
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* wait; hence the clock rate dependency.
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*
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* Supports 2 different timing parameters for both chip selects.
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*
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* Note 1: the sdrc_init_params_cs[01] must be sorted rate descending.
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* Note 2: If sdrc_init_params_cs_1 is not NULL it must be of same size
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* as sdrc_init_params_cs_0.
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*
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* Fills in the struct omap_sdrc_params * for each chip select.
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* Returns 0 upon success or -1 upon failure.
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*/
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int omap2_sdrc_get_params(unsigned long r,
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struct omap_sdrc_params **sdrc_cs0,
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struct omap_sdrc_params **sdrc_cs1)
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{
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struct omap_sdrc_params *sp0, *sp1;
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if (!sdrc_init_params_cs0)
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return -1;
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sp0 = sdrc_init_params_cs0;
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sp1 = sdrc_init_params_cs1;
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while (sp0->rate && sp0->rate != r) {
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sp0++;
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if (sdrc_init_params_cs1)
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sp1++;
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}
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if (!sp0->rate)
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return -1;
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*sdrc_cs0 = sp0;
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*sdrc_cs1 = sp1;
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return 0;
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}
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void __init omap2_set_globals_sdrc(struct omap_globals *omap2_globals)
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{
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omap2_sdrc_base = omap2_globals->sdrc;
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omap2_sms_base = omap2_globals->sms;
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}
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/**
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* omap2_sdrc_init - initialize SMS, SDRC devices on boot
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* @sdrc_cs[01]: pointers to a null-terminated list of struct omap_sdrc_params
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* Support for 2 chip selects timings
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*
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* Turn on smart idle modes for SDRAM scheduler and controller.
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* Program a known-good configuration for the SDRC to deal with buggy
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* bootloaders.
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*/
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void __init omap2_sdrc_init(struct omap_sdrc_params *sdrc_cs0,
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struct omap_sdrc_params *sdrc_cs1)
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{
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u32 l;
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l = sms_read_reg(SMS_SYSCONFIG);
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l &= ~(0x3 << 3);
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l |= (0x2 << 3);
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sms_write_reg(l, SMS_SYSCONFIG);
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l = sdrc_read_reg(SDRC_SYSCONFIG);
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l &= ~(0x3 << 3);
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l |= (0x2 << 3);
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sdrc_write_reg(l, SDRC_SYSCONFIG);
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sdrc_init_params_cs0 = sdrc_cs0;
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sdrc_init_params_cs1 = sdrc_cs1;
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/* XXX Enable SRFRONIDLEREQ here also? */
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/*
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* PWDENA should not be set due to 34xx erratum 1.150 - PWDENA
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* can cause random memory corruption
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*/
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l = (1 << SDRC_POWER_EXTCLKDIS_SHIFT) |
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(1 << SDRC_POWER_PAGEPOLICY_SHIFT);
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sdrc_write_reg(l, SDRC_POWER);
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}
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