arch/arm/mach-vexpress/dcscb.c

   1 /*
   2  * arch/arm/mach-vexpress/dcscb.c - Dual Cluster System Configuration Block
   3  *
   4  * Created by:  Nicolas Pitre, May 2012
   5  * Copyright:   (C) 2012-2013  Linaro Limited
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11
  12 #include <linux/init.h>
  13 #include <linux/kernel.h>
  14 #include <linux/io.h>
  15 #include <linux/errno.h>
  16 #include <linux/of_address.h>
  17 #include <linux/vexpress.h>
  18 #include <linux/arm-cci.h>
  19
  20 #include <asm/mcpm.h>
  21 #include <asm/proc-fns.h>
  22 #include <asm/cacheflush.h>
  23 #include <asm/cputype.h>
  24 #include <asm/cp15.h>
  25
  26
  27 #define RST_HOLD0       0x0
  28 #define RST_HOLD1       0x4
  29 #define SYS_SWRESET     0x8
  30 #define RST_STAT0       0xc
  31 #define RST_STAT1       0x10
  32 #define EAG_CFG_R       0x20
  33 #define EAG_CFG_W       0x24
  34 #define KFC_CFG_R       0x28
  35 #define KFC_CFG_W       0x2c
  36 #define DCS_CFG_R       0x30
  37
  38 static void __iomem *dcscb_base;
  39 static int dcscb_allcpus_mask[2];
  40
  41 static int dcscb_cpu_powerup(unsigned int cpu, unsigned int cluster)
  42 {
  43         unsigned int rst_hold, cpumask = (1 << cpu);
  44
  45         pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
  46         if (cluster >= 2 || !(cpumask & dcscb_allcpus_mask[cluster]))
  47                 return -EINVAL;
  48
  49         rst_hold = readl_relaxed(dcscb_base + RST_HOLD0 + cluster * 4);
  50         rst_hold &= ~(cpumask | (cpumask << 4));
  51         writel_relaxed(rst_hold, dcscb_base + RST_HOLD0 + cluster * 4);
  52         return 0;
  53 }
  54
  55 static int dcscb_cluster_powerup(unsigned int cluster)
  56 {
  57         unsigned int rst_hold;
  58
  59         pr_debug("%s: cluster %u\n", __func__, cluster);
  60         if (cluster >= 2)
  61                 return -EINVAL;
  62
  63         /* remove cluster reset and add individual CPU's reset */
  64         rst_hold = readl_relaxed(dcscb_base + RST_HOLD0 + cluster * 4);
  65         rst_hold &= ~(1 << 8);
  66         rst_hold |= dcscb_allcpus_mask[cluster];
  67         writel_relaxed(rst_hold, dcscb_base + RST_HOLD0 + cluster * 4);
  68         return 0;
  69 }
  70
  71 static void dcscb_cpu_powerdown_prepare(unsigned int cpu, unsigned int cluster)
  72 {
  73         unsigned int rst_hold;
  74
  75         pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
  76         BUG_ON(cluster >= 2 || !((1 << cpu) & dcscb_allcpus_mask[cluster]));
  77
  78         rst_hold = readl_relaxed(dcscb_base + RST_HOLD0 + cluster * 4);
  79         rst_hold |= (1 << cpu);
  80         writel_relaxed(rst_hold, dcscb_base + RST_HOLD0 + cluster * 4);
  81 }
  82
  83 static void dcscb_cluster_powerdown_prepare(unsigned int cluster)
  84 {
  85         unsigned int rst_hold;
  86
  87         pr_debug("%s: cluster %u\n", __func__, cluster);
  88         BUG_ON(cluster >= 2);
  89
  90         rst_hold = readl_relaxed(dcscb_base + RST_HOLD0 + cluster * 4);
  91         rst_hold |= (1 << 8);
  92         writel_relaxed(rst_hold, dcscb_base + RST_HOLD0 + cluster * 4);
  93 }
  94
  95 static void dcscb_cpu_cache_disable(void)
  96 {
  97         /* Disable and flush the local CPU cache. */
  98         v7_exit_coherency_flush(louis);
  99 }
 100
 101 static void dcscb_cluster_cache_disable(void)
 102 {
 103         /* Flush all cache levels for this cluster. */
 104         v7_exit_coherency_flush(all);
 105
 106         /*
 107          * A full outer cache flush could be needed at this point
 108          * on platforms with such a cache, depending on where the
 109          * outer cache sits. In some cases the notion of a "last
 110          * cluster standing" would need to be implemented if the
 111          * outer cache is shared across clusters. In any case, when
 112          * the outer cache needs flushing, there is no concurrent
 113          * access to the cache controller to worry about and no
 114          * special locking besides what is already provided by the
 115          * MCPM state machinery is needed.
 116          */
 117
 118         /*
 119          * Disable cluster-level coherency by masking
 120          * incoming snoops and DVM messages:
 121          */
 122         cci_disable_port_by_cpu(read_cpuid_mpidr());
 123 }
 124
 125 static const struct mcpm_platform_ops dcscb_power_ops = {
 126         .cpu_powerup            = dcscb_cpu_powerup,
 127         .cluster_powerup        = dcscb_cluster_powerup,
 128         .cpu_powerdown_prepare  = dcscb_cpu_powerdown_prepare,
 129         .cluster_powerdown_prepare = dcscb_cluster_powerdown_prepare,
 130         .cpu_cache_disable      = dcscb_cpu_cache_disable,
 131         .cluster_cache_disable  = dcscb_cluster_cache_disable,
 132 };
 133
 134 extern void dcscb_power_up_setup(unsigned int affinity_level);
 135
 136 static int __init dcscb_init(void)
 137 {
 138         struct device_node *node;
 139         unsigned int cfg;
 140         int ret;
 141
 142         if (!cci_probed())
 143                 return -ENODEV;
 144
 145         node = of_find_compatible_node(NULL, NULL, "arm,rtsm,dcscb");
 146         if (!node)
 147                 return -ENODEV;
 148         dcscb_base = of_iomap(node, 0);
 149         if (!dcscb_base)
 150                 return -EADDRNOTAVAIL;
 151         cfg = readl_relaxed(dcscb_base + DCS_CFG_R);
 152         dcscb_allcpus_mask[0] = (1 << (((cfg >> 16) >> (0 << 2)) & 0xf)) - 1;
 153         dcscb_allcpus_mask[1] = (1 << (((cfg >> 16) >> (1 << 2)) & 0xf)) - 1;
 154
 155         ret = mcpm_platform_register(&dcscb_power_ops);
 156         if (!ret)
 157                 ret = mcpm_sync_init(dcscb_power_up_setup);
 158         if (ret) {
 159                 iounmap(dcscb_base);
 160                 return ret;
 161         }
 162
 163         pr_info("VExpress DCSCB support installed\n");
 164
 165         /*
 166          * Future entries into the kernel can now go
 167          * through the cluster entry vectors.
 168          */
 169         vexpress_flags_set(__pa_symbol(mcpm_entry_point));
 170
 171         return 0;
 172 }
 173
 174 early_initcall(dcscb_init);