arch/arm/mach-omap2/prcm.c

   1 /*
   2  * linux/arch/arm/mach-omap2/prcm.c
   3  *
   4  * OMAP 24xx Power Reset and Clock Management (PRCM) functions
   5  *
   6  * Copyright (C) 2005 Nokia Corporation
   7  *
   8  * Written by Tony Lindgren <tony.lindgren@nokia.com>
   9  *
  10  * Copyright (C) 2007 Texas Instruments, Inc.
  11  * Rajendra Nayak <rnayak@ti.com>
  12  *
  13  * Some pieces of code Copyright (C) 2005 Texas Instruments, Inc.
  14  * Upgraded with OMAP4 support by Abhijit Pagare <abhijitpagare@ti.com>
  15  *
  16  * This program is free software; you can redistribute it and/or modify
  17  * it under the terms of the GNU General Public License version 2 as
  18  * published by the Free Software Foundation.
  19  */
  20
  21 #include <linux/kernel.h>
  22 #include <linux/init.h>
  23 #include <linux/clk.h>
  24 #include <linux/io.h>
  25 #include <linux/delay.h>
  26 #include <linux/export.h>
  27
  28 #include <mach/system.h>
  29 #include <plat/common.h>
  30 #include <plat/prcm.h>
  31 #include <plat/irqs.h>
  32
  33 #include "clock.h"
  34 #include "clock2xxx.h"
  35 #include "cm2xxx_3xxx.h"
  36 #include "prm2xxx_3xxx.h"
  37 #include "prm44xx.h"
  38 #include "prminst44xx.h"
  39 #include "prm-regbits-24xx.h"
  40 #include "prm-regbits-44xx.h"
  41 #include "control.h"
  42
  43 void __iomem *prm_base;
  44 void __iomem *cm_base;
  45 void __iomem *cm2_base;
  46
  47 #define MAX_MODULE_ENABLE_WAIT          100000
  48
  49 u32 omap_prcm_get_reset_sources(void)
  50 {
  51         /* XXX This presumably needs modification for 34XX */
  52         if (cpu_is_omap24xx() || cpu_is_omap34xx())
  53                 return omap2_prm_read_mod_reg(WKUP_MOD, OMAP2_RM_RSTST) & 0x7f;
  54         if (cpu_is_omap44xx())
  55                 return omap2_prm_read_mod_reg(WKUP_MOD, OMAP4_RM_RSTST) & 0x7f;
  56
  57         return 0;
  58 }
  59 EXPORT_SYMBOL(omap_prcm_get_reset_sources);
  60
  61 /* Resets clock rates and reboots the system. Only called from system.h */
  62 static void omap_prcm_arch_reset(char mode, const char *cmd)
  63 {
  64         s16 prcm_offs = 0;
  65
  66         if (cpu_is_omap24xx()) {
  67                 omap2xxx_clk_prepare_for_reboot();
  68
  69                 prcm_offs = WKUP_MOD;
  70         } else if (cpu_is_omap34xx()) {
  71                 prcm_offs = OMAP3430_GR_MOD;
  72                 omap3_ctrl_write_boot_mode((cmd ? (u8)*cmd : 0));
  73         } else if (cpu_is_omap44xx()) {
  74                 omap4_prminst_global_warm_sw_reset(); /* never returns */
  75         } else {
  76                 WARN_ON(1);
  77         }
  78
  79         /*
  80          * As per Errata i520, in some cases, user will not be able to
  81          * access DDR memory after warm-reset.
  82          * This situation occurs while the warm-reset happens during a read
  83          * access to DDR memory. In that particular condition, DDR memory
  84          * does not respond to a corrupted read command due to the warm
  85          * reset occurrence but SDRC is waiting for read completion.
  86          * SDRC is not sensitive to the warm reset, but the interconnect is
  87          * reset on the fly, thus causing a misalignment between SDRC logic,
  88          * interconnect logic and DDR memory state.
  89          * WORKAROUND:
  90          * Steps to perform before a Warm reset is trigged:
  91          * 1. enable self-refresh on idle request
  92          * 2. put SDRC in idle
  93          * 3. wait until SDRC goes to idle
  94          * 4. generate SW reset (Global SW reset)
  95          *
  96          * Steps to be performed after warm reset occurs (in bootloader):
  97          * if HW warm reset is the source, apply below steps before any
  98          * accesses to SDRAM:
  99          * 1. Reset SMS and SDRC and wait till reset is complete
 100          * 2. Re-initialize SMS, SDRC and memory
 101          *
 102          * NOTE: Above work around is required only if arch reset is implemented
 103          * using Global SW reset(GLOBAL_SW_RST). DPLL3 reset does not need
 104          * the WA since it resets SDRC as well as part of cold reset.
 105          */
 106
 107         /* XXX should be moved to some OMAP2/3 specific code */
 108         omap2_prm_set_mod_reg_bits(OMAP_RST_DPLL3_MASK, prcm_offs,
 109                                    OMAP2_RM_RSTCTRL);
 110         omap2_prm_read_mod_reg(prcm_offs, OMAP2_RM_RSTCTRL); /* OCP barrier */
 111 }
 112
 113 void (*arch_reset)(char, const char *) = omap_prcm_arch_reset;
 114
 115 /**
 116  * omap2_cm_wait_idlest - wait for IDLEST bit to indicate module readiness
 117  * @reg: physical address of module IDLEST register
 118  * @mask: value to mask against to determine if the module is active
 119  * @idlest: idle state indicator (0 or 1) for the clock
 120  * @name: name of the clock (for printk)
 121  *
 122  * Returns 1 if the module indicated readiness in time, or 0 if it
 123  * failed to enable in roughly MAX_MODULE_ENABLE_WAIT microseconds.
 124  *
 125  * XXX This function is deprecated.  It should be removed once the
 126  * hwmod conversion is complete.
 127  */
 128 int omap2_cm_wait_idlest(void __iomem *reg, u32 mask, u8 idlest,
 129                                 const char *name)
 130 {
 131         int i = 0;
 132         int ena = 0;
 133
 134         if (idlest)
 135                 ena = 0;
 136         else
 137                 ena = mask;
 138
 139         /* Wait for lock */
 140         omap_test_timeout(((__raw_readl(reg) & mask) == ena),
 141                           MAX_MODULE_ENABLE_WAIT, i);
 142
 143         if (i < MAX_MODULE_ENABLE_WAIT)
 144                 pr_debug("cm: Module associated with clock %s ready after %d "
 145                          "loops\n", name, i);
 146         else
 147                 pr_err("cm: Module associated with clock %s didn't enable in "
 148                        "%d tries\n", name, MAX_MODULE_ENABLE_WAIT);
 149
 150         return (i < MAX_MODULE_ENABLE_WAIT) ? 1 : 0;
 151 };
 152
 153 void __init omap2_set_globals_prcm(struct omap_globals *omap2_globals)
 154 {
 155         /* Static mapping, never released */
 156         if (omap2_globals->prm) {
 157                 prm_base = ioremap(omap2_globals->prm, SZ_8K);
 158                 WARN_ON(!prm_base);
 159         }
 160         if (omap2_globals->cm) {
 161                 cm_base = ioremap(omap2_globals->cm, SZ_8K);
 162                 WARN_ON(!cm_base);
 163         }
 164         if (omap2_globals->cm2) {
 165                 cm2_base = ioremap(omap2_globals->cm2, SZ_8K);
 166                 WARN_ON(!cm2_base);
 167         }
 168 }