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// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2018 Arm Ltd
* Author: Liviu Dudau <liviu.dudau@foss.arm.com>
*
*/
#include <common.h>
#include <dm.h>
#include <malloc.h>
#include <dm/read.h>
#include <asm/io.h>
#include <linux/bitops.h>
#include <linux/delay.h>
#include <misc.h>
#define SYS_CFGDATA 0xa0
#define SYS_CFGCTRL 0xa4
#define SYS_CFGCTRL_START BIT(31)
#define SYS_CFGCTRL_WRITE BIT(30)
#define SYS_CFGSTAT 0xa8
#define SYS_CFGSTAT_ERR BIT(1)
#define SYS_CFGSTAT_COMPLETE BIT(0)
struct vexpress_config_sysreg {
phys_addr_t addr;
u32 site;
};
static int vexpress_config_exec(struct vexpress_config_sysreg *syscfg,
bool write, void *buf, int size)
{
u32 cmd, status, tries = 100;
cmd = (*(u32 *)buf) | SYS_CFGCTRL_START | (syscfg->site << 16);
if (!write) {
/* write a canary in the data register for reads */
writel(0xdeadbeef, syscfg->addr + SYS_CFGDATA);
} else {
cmd |= SYS_CFGCTRL_WRITE;
writel(((u32 *)buf)[1], syscfg->addr + SYS_CFGDATA);
}
writel(0, syscfg->addr + SYS_CFGSTAT);
writel(cmd, syscfg->addr + SYS_CFGCTRL);
/* completion of command takes ages, go to sleep (150us) */
do {
udelay(150);
status = readl(syscfg->addr + SYS_CFGSTAT);
if (status & SYS_CFGSTAT_ERR)
return -EFAULT;
} while (--tries && !(status & SYS_CFGSTAT_COMPLETE));
if (!tries)
return -ETIMEDOUT;
if (!write)
(*(u32 *)buf) = readl(syscfg->addr + SYS_CFGDATA);
return 0;
}
static int vexpress_config_read(struct udevice *dev,
int offset, void *buf, int size)
{
struct vexpress_config_sysreg *priv = dev_get_uclass_priv(dev);
if (size != sizeof(u32))
return -EINVAL;
return vexpress_config_exec(priv, false, buf, size);
}
static int vexpress_config_write(struct udevice *dev,
int offset, const void *buf, int size)
{
struct vexpress_config_sysreg *priv = dev_get_uclass_priv(dev);
if (size != sizeof(u32) * 2)
return -EINVAL;
return vexpress_config_exec(priv, true, (void *)buf, size);
}
static struct misc_ops vexpress_config_ops = {
.read = vexpress_config_read,
.write = vexpress_config_write,
};
static int vexpress_config_probe(struct udevice *dev)
{
struct ofnode_phandle_args args;
struct vexpress_config_sysreg *priv;
const char *prop;
int err, prop_size;
err = dev_read_phandle_with_args(dev, "arm,vexpress,config-bridge",
NULL, 0, 0, &args);
if (err)
return err;
prop = ofnode_get_property(args.node, "compatible", &prop_size);
if (!prop || (strncmp(prop, "arm,vexpress-sysreg", 19) != 0))
return -ENOENT;
priv = calloc(1, sizeof(*priv));
if (!priv)
return -ENOMEM;
dev->uclass_priv = priv;
priv->addr = ofnode_get_addr(args.node);
return dev_read_u32(dev, "arm,vexpress,site", &priv->site);
}
static const struct udevice_id vexpress_config_ids[] = {
{ .compatible = "arm,vexpress,config-bus" },
{ }
};
U_BOOT_DRIVER(vexpress_config_drv) = {
.name = "vexpress_config_bus",
.id = UCLASS_MISC,
.of_match = vexpress_config_ids,
.bind = dm_scan_fdt_dev,
.probe = vexpress_config_probe,
.ops = &vexpress_config_ops,
};
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