drivers/soc/bcm/brcmstb/biuctrl.c

   1 /*
   2  * Broadcom STB SoCs Bus Unit Interface controls
   3  *
   4  * Copyright (C) 2015, Broadcom Corporation
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  */
  15
  16 #define pr_fmt(fmt)     "brcmstb: " KBUILD_MODNAME ": " fmt
  17
  18 #include <linux/kernel.h>
  19 #include <linux/io.h>
  20 #include <linux/of_address.h>
  21 #include <linux/syscore_ops.h>
  22 #include <linux/soc/brcmstb/brcmstb.h>
  23
  24 #define CPU_CREDIT_REG_OFFSET                   0x184
  25 #define  CPU_CREDIT_REG_MCPx_WR_PAIRING_EN_MASK 0x70000000
  26
  27 static void __iomem *cpubiuctrl_base;
  28 static bool mcp_wr_pairing_en;
  29
  30 static int __init mcp_write_pairing_set(void)
  31 {
  32         u32 creds = 0;
  33
  34         if (!cpubiuctrl_base)
  35                 return -1;
  36
  37         creds = readl_relaxed(cpubiuctrl_base + CPU_CREDIT_REG_OFFSET);
  38         if (mcp_wr_pairing_en) {
  39                 pr_info("MCP: Enabling write pairing\n");
  40                 writel_relaxed(creds | CPU_CREDIT_REG_MCPx_WR_PAIRING_EN_MASK,
  41                              cpubiuctrl_base + CPU_CREDIT_REG_OFFSET);
  42         } else if (creds & CPU_CREDIT_REG_MCPx_WR_PAIRING_EN_MASK) {
  43                 pr_info("MCP: Disabling write pairing\n");
  44                 writel_relaxed(creds & ~CPU_CREDIT_REG_MCPx_WR_PAIRING_EN_MASK,
  45                                 cpubiuctrl_base + CPU_CREDIT_REG_OFFSET);
  46         } else {
  47                 pr_info("MCP: Write pairing already disabled\n");
  48         }
  49
  50         return 0;
  51 }
  52
  53 static int __init setup_hifcpubiuctrl_regs(void)
  54 {
  55         struct device_node *np;
  56         int ret = 0;
  57
  58         np = of_find_compatible_node(NULL, NULL, "brcm,brcmstb-cpu-biu-ctrl");
  59         if (!np) {
  60                 pr_err("missing BIU control node\n");
  61                 return -ENODEV;
  62         }
  63
  64         cpubiuctrl_base = of_iomap(np, 0);
  65         if (!cpubiuctrl_base) {
  66                 pr_err("failed to remap BIU control base\n");
  67                 ret = -ENOMEM;
  68                 goto out;
  69         }
  70
  71         mcp_wr_pairing_en = of_property_read_bool(np, "brcm,write-pairing");
  72 out:
  73         of_node_put(np);
  74         return ret;
  75 }
  76
  77 #ifdef CONFIG_PM_SLEEP
  78 static u32 cpu_credit_reg_dump;  /* for save/restore */
  79
  80 static int brcmstb_cpu_credit_reg_suspend(void)
  81 {
  82         if (cpubiuctrl_base)
  83                 cpu_credit_reg_dump =
  84                         readl_relaxed(cpubiuctrl_base + CPU_CREDIT_REG_OFFSET);
  85         return 0;
  86 }
  87
  88 static void brcmstb_cpu_credit_reg_resume(void)
  89 {
  90         if (cpubiuctrl_base)
  91                 writel_relaxed(cpu_credit_reg_dump,
  92                                 cpubiuctrl_base + CPU_CREDIT_REG_OFFSET);
  93 }
  94
  95 static struct syscore_ops brcmstb_cpu_credit_syscore_ops = {
  96         .suspend = brcmstb_cpu_credit_reg_suspend,
  97         .resume = brcmstb_cpu_credit_reg_resume,
  98 };
  99 #endif
 100
 101
 102 void __init brcmstb_biuctrl_init(void)
 103 {
 104         int ret;
 105
 106         setup_hifcpubiuctrl_regs();
 107
 108         ret = mcp_write_pairing_set();
 109         if (ret) {
 110                 pr_err("MCP: Unable to disable write pairing!\n");
 111                 return;
 112         }
 113
 114 #ifdef CONFIG_PM_SLEEP
 115         register_syscore_ops(&brcmstb_cpu_credit_syscore_ops);
 116 #endif
 117 }