drivers/soc/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
  23 #define CPU_CREDIT_REG_OFFSET                   0x184
  24 #define  CPU_CREDIT_REG_MCPx_WR_PAIRING_EN_MASK 0x70000000
  25
  26 static void __iomem *cpubiuctrl_base;
  27 static bool mcp_wr_pairing_en;
  28
  29 static int __init mcp_write_pairing_set(void)
  30 {
  31         u32 creds = 0;
  32
  33         if (!cpubiuctrl_base)
  34                 return -1;
  35
  36         creds = readl_relaxed(cpubiuctrl_base + CPU_CREDIT_REG_OFFSET);
  37         if (mcp_wr_pairing_en) {
  38                 pr_info("MCP: Enabling write pairing\n");
  39                 writel_relaxed(creds | CPU_CREDIT_REG_MCPx_WR_PAIRING_EN_MASK,
  40                              cpubiuctrl_base + CPU_CREDIT_REG_OFFSET);
  41         } else if (creds & CPU_CREDIT_REG_MCPx_WR_PAIRING_EN_MASK) {
  42                 pr_info("MCP: Disabling write pairing\n");
  43                 writel_relaxed(creds & ~CPU_CREDIT_REG_MCPx_WR_PAIRING_EN_MASK,
  44                                 cpubiuctrl_base + CPU_CREDIT_REG_OFFSET);
  45         } else {
  46                 pr_info("MCP: Write pairing already disabled\n");
  47         }
  48
  49         return 0;
  50 }
  51
  52 static int __init setup_hifcpubiuctrl_regs(void)
  53 {
  54         struct device_node *np;
  55         int ret = 0;
  56
  57         np = of_find_compatible_node(NULL, NULL, "brcm,brcmstb-cpu-biu-ctrl");
  58         if (!np) {
  59                 pr_err("missing BIU control node\n");
  60                 return -ENODEV;
  61         }
  62
  63         cpubiuctrl_base = of_iomap(np, 0);
  64         if (!cpubiuctrl_base) {
  65                 pr_err("failed to remap BIU control base\n");
  66                 ret = -ENOMEM;
  67                 goto out;
  68         }
  69
  70         mcp_wr_pairing_en = of_property_read_bool(np, "brcm,write-pairing");
  71 out:
  72         of_node_put(np);
  73         return ret;
  74 }
  75
  76 #ifdef CONFIG_PM_SLEEP
  77 static u32 cpu_credit_reg_dump;  /* for save/restore */
  78
  79 static int brcmstb_cpu_credit_reg_suspend(void)
  80 {
  81         if (cpubiuctrl_base)
  82                 cpu_credit_reg_dump =
  83                         readl_relaxed(cpubiuctrl_base + CPU_CREDIT_REG_OFFSET);
  84         return 0;
  85 }
  86
  87 static void brcmstb_cpu_credit_reg_resume(void)
  88 {
  89         if (cpubiuctrl_base)
  90                 writel_relaxed(cpu_credit_reg_dump,
  91                                 cpubiuctrl_base + CPU_CREDIT_REG_OFFSET);
  92 }
  93
  94 static struct syscore_ops brcmstb_cpu_credit_syscore_ops = {
  95         .suspend = brcmstb_cpu_credit_reg_suspend,
  96         .resume = brcmstb_cpu_credit_reg_resume,
  97 };
  98 #endif
  99
 100
 101 void __init brcmstb_biuctrl_init(void)
 102 {
 103         int ret;
 104
 105         setup_hifcpubiuctrl_regs();
 106
 107         ret = mcp_write_pairing_set();
 108         if (ret) {
 109                 pr_err("MCP: Unable to disable write pairing!\n");
 110                 return;
 111         }
 112
 113 #ifdef CONFIG_PM_SLEEP
 114         register_syscore_ops(&brcmstb_cpu_credit_syscore_ops);
 115 #endif
 116 }