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/*
* Broadcom BCM63138 PMB initialization for secondary CPU(s)
*
* Copyright (C) 2015 Broadcom Corporation
* Author: Florian Fainelli <f.fainelli@gmail.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
#include <linux/kernel.h>
#include <linux/io.h>
#include <linux/spinlock.h>
#include <linux/reset/bcm63xx_pmb.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include "bcm63xx_smp.h"
/* ARM Control register definitions */
#define CORE_PWR_CTRL_SHIFT 0
#define CORE_PWR_CTRL_MASK 0x3
#define PLL_PWR_ON BIT(8)
#define PLL_LDO_PWR_ON BIT(9)
#define PLL_CLAMP_ON BIT(10)
#define CPU_RESET_N(x) BIT(13 + (x))
#define NEON_RESET_N BIT(15)
#define PWR_CTRL_STATUS_SHIFT 28
#define PWR_CTRL_STATUS_MASK 0x3
#define PWR_DOWN_SHIFT 30
#define PWR_DOWN_MASK 0x3
/* CPU Power control register definitions */
#define MEM_PWR_OK BIT(0)
#define MEM_PWR_ON BIT(1)
#define MEM_CLAMP_ON BIT(2)
#define MEM_PWR_OK_STATUS BIT(4)
#define MEM_PWR_ON_STATUS BIT(5)
#define MEM_PDA_SHIFT 8
#define MEM_PDA_MASK 0xf
#define MEM_PDA_CPU_MASK 0x1
#define MEM_PDA_NEON_MASK 0xf
#define CLAMP_ON BIT(15)
#define PWR_OK_SHIFT 16
#define PWR_OK_MASK 0xf
#define PWR_ON_SHIFT 20
#define PWR_CPU_MASK 0x03
#define PWR_NEON_MASK 0x01
#define PWR_ON_MASK 0xf
#define PWR_OK_STATUS_SHIFT 24
#define PWR_OK_STATUS_MASK 0xf
#define PWR_ON_STATUS_SHIFT 28
#define PWR_ON_STATUS_MASK 0xf
#define ARM_CONTROL 0x30
#define ARM_PWR_CONTROL_BASE 0x34
#define ARM_PWR_CONTROL(x) (ARM_PWR_CONTROL_BASE + (x) * 0x4)
#define ARM_NEON_L2 0x3c
/* Perform a value write, then spin until the value shifted by
* shift is seen, masked with mask and is different from cond.
*/
static int bpcm_wr_rd_mask(void __iomem *master,
unsigned int addr, u32 off, u32 *val,
u32 shift, u32 mask, u32 cond)
{
int ret;
ret = bpcm_wr(master, addr, off, *val);
if (ret)
return ret;
do {
ret = bpcm_rd(master, addr, off, val);
if (ret)
return ret;
cpu_relax();
} while (((*val >> shift) & mask) != cond);
return ret;
}
/* Global lock to serialize accesses to the PMB registers while we
* are bringing up the secondary CPU
*/
static DEFINE_SPINLOCK(pmb_lock);
static int bcm63xx_pmb_get_resources(struct device_node *dn,
void __iomem **base,
unsigned int *cpu,
unsigned int *addr)
{
struct of_phandle_args args;
int ret;
ret = of_property_read_u32(dn, "reg", cpu);
if (ret) {
pr_err("CPU is missing a reg node\n");
return ret;
}
ret = of_parse_phandle_with_args(dn, "resets", "#reset-cells",
0, &args);
if (ret) {
pr_err("CPU is missing a resets phandle\n");
return ret;
}
if (args.args_count != 2) {
pr_err("reset-controller does not conform to reset-cells\n");
return -EINVAL;
}
*base = of_iomap(args.np, 0);
if (!*base) {
pr_err("failed remapping PMB register\n");
return -ENOMEM;
}
/* We do not need the number of zones */
*addr = args.args[0];
return 0;
}
int bcm63xx_pmb_power_on_cpu(struct device_node *dn)
{
void __iomem *base;
unsigned int cpu, addr;
unsigned long flags;
u32 val, ctrl;
int ret;
ret = bcm63xx_pmb_get_resources(dn, &base, &cpu, &addr);
if (ret)
return ret;
/* We would not know how to enable a third and greater CPU */
WARN_ON(cpu > 1);
spin_lock_irqsave(&pmb_lock, flags);
/* Check if the CPU is already on and save the ARM_CONTROL register
* value since we will use it later for CPU de-assert once done with
* the CPU-specific power sequence
*/
ret = bpcm_rd(base, addr, ARM_CONTROL, &ctrl);
if (ret)
goto out;
if (ctrl & CPU_RESET_N(cpu)) {
pr_info("PMB: CPU%d is already powered on\n", cpu);
ret = 0;
goto out;
}
/* Power on PLL */
ret = bpcm_rd(base, addr, ARM_PWR_CONTROL(cpu), &val);
if (ret)
goto out;
val |= (PWR_CPU_MASK << PWR_ON_SHIFT);
ret = bpcm_wr_rd_mask(base, addr, ARM_PWR_CONTROL(cpu), &val,
PWR_ON_STATUS_SHIFT, PWR_CPU_MASK, PWR_CPU_MASK);
if (ret)
goto out;
val |= (PWR_CPU_MASK << PWR_OK_SHIFT);
ret = bpcm_wr_rd_mask(base, addr, ARM_PWR_CONTROL(cpu), &val,
PWR_OK_STATUS_SHIFT, PWR_CPU_MASK, PWR_CPU_MASK);
if (ret)
goto out;
val &= ~CLAMP_ON;
ret = bpcm_wr(base, addr, ARM_PWR_CONTROL(cpu), val);
if (ret)
goto out;
/* Power on CPU<N> RAM */
val &= ~(MEM_PDA_MASK << MEM_PDA_SHIFT);
ret = bpcm_wr(base, addr, ARM_PWR_CONTROL(cpu), val);
if (ret)
goto out;
val |= MEM_PWR_ON;
ret = bpcm_wr_rd_mask(base, addr, ARM_PWR_CONTROL(cpu), &val,
0, MEM_PWR_ON_STATUS, MEM_PWR_ON_STATUS);
if (ret)
goto out;
val |= MEM_PWR_OK;
ret = bpcm_wr_rd_mask(base, addr, ARM_PWR_CONTROL(cpu), &val,
0, MEM_PWR_OK_STATUS, MEM_PWR_OK_STATUS);
if (ret)
goto out;
val &= ~MEM_CLAMP_ON;
ret = bpcm_wr(base, addr, ARM_PWR_CONTROL(cpu), val);
if (ret)
goto out;
/* De-assert CPU reset */
ctrl |= CPU_RESET_N(cpu);
ret = bpcm_wr(base, addr, ARM_CONTROL, ctrl);
out:
spin_unlock_irqrestore(&pmb_lock, flags);
iounmap(base);
return ret;
}
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