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