/*
* Xilinx SLCR driver
*
* Copyright (c) 2011-2013 Xilinx Inc.
*
* 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.
*
* You should have received a copy of the GNU General Public
* License along with this program; if not, write to the Free
* Software Foundation, Inc., 675 Mass Ave, Cambridge, MA
* 02139, USA.
*/
#include <linux/io.h>
#include <linux/reboot.h>
#include <linux/mfd/syscon.h>
#include <linux/of_address.h>
#include <linux/regmap.h>
#include <linux/clk/zynq.h>
#include "common.h"
/* register offsets */
#define SLCR_UNLOCK_OFFSET 0x8 /* SCLR unlock register */
#define SLCR_PS_RST_CTRL_OFFSET 0x200 /* PS Software Reset Control */
#define SLCR_A9_CPU_RST_CTRL_OFFSET 0x244 /* CPU Software Reset Control */
#define SLCR_REBOOT_STATUS_OFFSET 0x258 /* PS Reboot Status */
#define SLCR_PSS_IDCODE 0x530 /* PS IDCODE */
#define SLCR_UNLOCK_MAGIC 0xDF0D
#define SLCR_A9_CPU_CLKSTOP 0x10
#define SLCR_A9_CPU_RST 0x1
#define SLCR_PSS_IDCODE_DEVICE_SHIFT 12
#define SLCR_PSS_IDCODE_DEVICE_MASK 0x1F
static void __iomem *zynq_slcr_base;
static struct regmap *zynq_slcr_regmap;
/**
* zynq_slcr_write - Write to a register in SLCR block
*
* @val: Value to write to the register
* @offset: Register offset in SLCR block
*
* Return: a negative value on error, 0 on success
*/
static int zynq_slcr_write(u32 val, u32 offset)
{
return regmap_write(zynq_slcr_regmap, offset, val);
}
/**
* zynq_slcr_read - Read a register in SLCR block
*
* @val: Pointer to value to be read from SLCR
* @offset: Register offset in SLCR block
*
* Return: a negative value on error, 0 on success
*/
static int zynq_slcr_read(u32 *val, u32 offset)
{
return regmap_read(zynq_slcr_regmap, offset, val);
}
/**
* zynq_slcr_unlock - Unlock SLCR registers
*
* Return: a negative value on error, 0 on success
*/
static inline int zynq_slcr_unlock(void)
{
zynq_slcr_write(SLCR_UNLOCK_MAGIC, SLCR_UNLOCK_OFFSET);
return 0;
}
/**
* zynq_slcr_get_device_id - Read device code id
*
* Return: Device code id
*/
u32 zynq_slcr_get_device_id(void)
{
u32 val;
zynq_slcr_read(&val, SLCR_PSS_IDCODE);
val >>= SLCR_PSS_IDCODE_DEVICE_SHIFT;
val &= SLCR_PSS_IDCODE_DEVICE_MASK;
return val;
}
/**
* zynq_slcr_system_restart - Restart the entire system.
*
* @nb: Pointer to restart notifier block (unused)
* @action: Reboot mode (unused)
* @data: Restart handler private data (unused)
*
* Return: 0 always
*/
static
int zynq_slcr_system_restart(struct notifier_block *nb,
unsigned long action, void *data)
{
u32 reboot;
/*
* Clear 0x0F000000 bits of reboot status register to workaround
* the FSBL not loading the bitstream after soft-reboot
* This is a temporary solution until we know more.
*/
zynq_slcr_read(&reboot, SLCR_REBOOT_STATUS_OFFSET);
zynq_slcr_write(reboot & 0xF0FFFFFF, SLCR_REBOOT_STATUS_OFFSET);
zynq_slcr_write(1, SLCR_PS_RST_CTRL_OFFSET);
return 0;
}
static struct notifier_block zynq_slcr_restart_nb = {
.notifier_call = zynq_slcr_system_restart,
.priority = 192,
};
/**
* zynq_slcr_cpu_start - Start cpu
* @cpu: cpu number
*/
void zynq_slcr_cpu_start(int cpu)
{
u32 reg;
zynq_slcr_read(®, SLCR_A9_CPU_RST_CTRL_OFFSET);
reg &= ~(SLCR_A9_CPU_RST << cpu);
zynq_slcr_write(reg, SLCR_A9_CPU_RST_CTRL_OFFSET);
reg &= ~(SLCR_A9_CPU_CLKSTOP << cpu);
zynq_slcr_write(reg, SLCR_A9_CPU_RST_CTRL_OFFSET);
zynq_slcr_cpu_state_write(cpu, false);
}
/**
* zynq_slcr_cpu_stop - Stop cpu
* @cpu: cpu number
*/
void zynq_slcr_cpu_stop(int cpu)
{
u32 reg;
zynq_slcr_read(®, SLCR_A9_CPU_RST_CTRL_OFFSET);
reg |= (SLCR_A9_CPU_CLKSTOP | SLCR_A9_CPU_RST) << cpu;
zynq_slcr_write(reg, SLCR_A9_CPU_RST_CTRL_OFFSET);
}
/**
* zynq_slcr_cpu_state - Read/write cpu state
* @cpu: cpu number
*
* SLCR_REBOOT_STATUS save upper 2 bits (31/30 cpu states for cpu0 and cpu1)
* 0 means cpu is running, 1 cpu is going to die.
*
* Return: true if cpu is running, false if cpu is going to die
*/
bool zynq_slcr_cpu_state_read(int cpu)
{
u32 state;
state = readl(zynq_slcr_base + SLCR_REBOOT_STATUS_OFFSET);
state &= 1 << (31 - cpu);
return !state;
}
/**
* zynq_slcr_cpu_state - Read/write cpu state
* @cpu: cpu number
* @die: cpu state - true if cpu is going to die
*
* SLCR_REBOOT_STATUS save upper 2 bits (31/30 cpu states for cpu0 and cpu1)
* 0 means cpu is running, 1 cpu is going to die.
*/
void zynq_slcr_cpu_state_write(int cpu, bool die)
{
u32 state, mask;
state = readl(zynq_slcr_base + SLCR_REBOOT_STATUS_OFFSET);
mask = 1 << (31 - cpu);
if (die)
state |= mask;
else
state &= ~mask;
writel(state, zynq_slcr_base + SLCR_REBOOT_STATUS_OFFSET);
}
/**
* zynq_early_slcr_init - Early slcr init function
*
* Return: 0 on success, negative errno otherwise.
*
* Called very early during boot from platform code to unlock SLCR.
*/
int __init zynq_early_slcr_init(void)
{
struct device_node *np;
np = of_find_compatible_node(NULL, NULL, "xlnx,zynq-slcr");
if (!np) {
pr_err("%s: no slcr node found\n", __func__);
BUG();
}
zynq_slcr_base = of_iomap(np, 0);
if (!zynq_slcr_base) {
pr_err("%s: Unable to map I/O memory\n", __func__);
BUG();
}
np->data = (__force void *)zynq_slcr_base;
zynq_slcr_regmap = syscon_regmap_lookup_by_compatible("xlnx,zynq-slcr");
if (IS_ERR(zynq_slcr_regmap)) {
pr_err("%s: failed to find zynq-slcr\n", __func__);
return -ENODEV;
}
/* unlock the SLCR so that registers can be changed */
zynq_slcr_unlock();
register_restart_handler(&zynq_slcr_restart_nb);
pr_info("%s mapped to %p\n", np->name, zynq_slcr_base);
of_node_put(np);
return 0;
}