uniphier-system-bus.c
/*
* Copyright (C) 2015 Masahiro Yamada <yamada.masahiro@socionext.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.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/io.h>
#include <linux/log2.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
/* System Bus Controller registers */
#define UNIPHIER_SBC_BASE 0x100 /* base address of bank0 space */
#define UNIPHIER_SBC_BASE_BE BIT(0) /* bank_enable */
#define UNIPHIER_SBC_CTRL0 0x200 /* timing parameter 0 of bank0 */
#define UNIPHIER_SBC_CTRL1 0x204 /* timing parameter 1 of bank0 */
#define UNIPHIER_SBC_CTRL2 0x208 /* timing parameter 2 of bank0 */
#define UNIPHIER_SBC_CTRL3 0x20c /* timing parameter 3 of bank0 */
#define UNIPHIER_SBC_CTRL4 0x300 /* timing parameter 4 of bank0 */
#define UNIPHIER_SBC_STRIDE 0x10 /* register stride to next bank */
#define UNIPHIER_SBC_NR_BANKS 8 /* number of banks (chip select) */
#define UNIPHIER_SBC_BASE_DUMMY 0xffffffff /* data to squash bank 0, 1 */
struct uniphier_system_bus_bank {
u32 base;
u32 end;
};
struct uniphier_system_bus_priv {
struct device *dev;
void __iomem *membase;
struct uniphier_system_bus_bank bank[UNIPHIER_SBC_NR_BANKS];
};
static int uniphier_system_bus_add_bank(struct uniphier_system_bus_priv *priv,
int bank, u32 addr, u64 paddr, u32 size)
{
u64 end, mask;
dev_dbg(priv->dev,
"range found: bank = %d, addr = %08x, paddr = %08llx, size = %08x\n",
bank, addr, paddr, size);
if (bank >= ARRAY_SIZE(priv->bank)) {
dev_err(priv->dev, "unsupported bank number %d\n", bank);
return -EINVAL;
}
if (priv->bank[bank].base || priv->bank[bank].end) {
dev_err(priv->dev,
"range for bank %d has already been specified\n", bank);
return -EINVAL;
}
if (paddr > U32_MAX) {
dev_err(priv->dev, "base address %llx is too high\n", paddr);
return -EINVAL;
}
end = paddr + size;
if (addr > paddr) {
dev_err(priv->dev,
"base %08x cannot be mapped to %08llx of parent\n",
addr, paddr);
return -EINVAL;
}
paddr -= addr;
paddr = round_down(paddr, 0x00020000);
end = round_up(end, 0x00020000);
if (end > U32_MAX) {
dev_err(priv->dev, "end address %08llx is too high\n", end);
return -EINVAL;
}
mask = paddr ^ (end - 1);
mask = roundup_pow_of_two(mask);
paddr = round_down(paddr, mask);
end = round_up(end, mask);
priv->bank[bank].base = paddr;
priv->bank[bank].end = end;
dev_dbg(priv->dev, "range added: bank = %d, addr = %08x, end = %08x\n",
bank, priv->bank[bank].base, priv->bank[bank].end);
return 0;
}
static int uniphier_system_bus_check_overlap(
const struct uniphier_system_bus_priv *priv)
{
int i, j;
for (i = 0; i < ARRAY_SIZE(priv->bank); i++) {
for (j = i + 1; j < ARRAY_SIZE(priv->bank); j++) {
if (priv->bank[i].end > priv->bank[j].base &&
priv->bank[i].base < priv->bank[j].end) {
dev_err(priv->dev,
"region overlap between bank%d and bank%d\n",
i, j);
return -EINVAL;
}
}
}
return 0;
}
static void uniphier_system_bus_check_boot_swap(
struct uniphier_system_bus_priv *priv)
{
void __iomem *base_reg = priv->membase + UNIPHIER_SBC_BASE;
int is_swapped;
is_swapped = !(readl(base_reg) & UNIPHIER_SBC_BASE_BE);
dev_dbg(priv->dev, "Boot Swap: %s\n", is_swapped ? "on" : "off");
/*
* If BOOT_SWAP was asserted on power-on-reset, the CS0 and CS1 are
* swapped. In this case, bank0 and bank1 should be swapped as well.
*/
if (is_swapped)
swap(priv->bank[0], priv->bank[1]);
}
static void uniphier_system_bus_set_reg(
const struct uniphier_system_bus_priv *priv)
{
void __iomem *base_reg = priv->membase + UNIPHIER_SBC_BASE;
u32 base, end, mask, val;
int i;
for (i = 0; i < ARRAY_SIZE(priv->bank); i++) {
base = priv->bank[i].base;
end = priv->bank[i].end;
if (base == end) {
/*
* If SBC_BASE0 or SBC_BASE1 is set to zero, the access
* to anywhere in the system bus space is routed to
* bank 0 (if boot swap if off) or bank 1 (if boot swap
* if on). It means that CPUs cannot get access to
* bank 2 or later. In other words, bank 0/1 cannot
* be disabled even if its bank_enable bits is cleared.
* This seems odd, but it is how this hardware goes.
* As a workaround, dummy data (0xffffffff) should be
* set when the bank 0/1 is unused. As for bank 2 and
* later, they can be simply disable by clearing the
* bank_enable bit.
*/
if (i < 2)
val = UNIPHIER_SBC_BASE_DUMMY;
else
val = 0;
} else {
mask = base ^ (end - 1);
val = base & 0xfffe0000;
val |= (~mask >> 16) & 0xfffe;
val |= UNIPHIER_SBC_BASE_BE;
}
dev_dbg(priv->dev, "SBC_BASE[%d] = 0x%08x\n", i, val);
writel(val, base_reg + UNIPHIER_SBC_STRIDE * i);
}
}
static int uniphier_system_bus_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct uniphier_system_bus_priv *priv;
struct resource *regs;
const __be32 *ranges;
u32 cells, addr, size;
u64 paddr;
int pna, bank, rlen, rone, ret;
priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
priv->membase = devm_ioremap_resource(dev, regs);
if (IS_ERR(priv->membase))
return PTR_ERR(priv->membase);
priv->dev = dev;
pna = of_n_addr_cells(dev->of_node);
ret = of_property_read_u32(dev->of_node, "#address-cells", &cells);
if (ret) {
dev_err(dev, "failed to get #address-cells\n");
return ret;
}
if (cells != 2) {
dev_err(dev, "#address-cells must be 2\n");
return -EINVAL;
}
ret = of_property_read_u32(dev->of_node, "#size-cells", &cells);
if (ret) {
dev_err(dev, "failed to get #size-cells\n");
return ret;
}
if (cells != 1) {
dev_err(dev, "#size-cells must be 1\n");
return -EINVAL;
}
ranges = of_get_property(dev->of_node, "ranges", &rlen);
if (!ranges) {
dev_err(dev, "failed to get ranges property\n");
return -ENOENT;
}
rlen /= sizeof(*ranges);
rone = pna + 2;
for (; rlen >= rone; rlen -= rone) {
bank = be32_to_cpup(ranges++);
addr = be32_to_cpup(ranges++);
paddr = of_translate_address(dev->of_node, ranges);
if (paddr == OF_BAD_ADDR)
return -EINVAL;
ranges += pna;
size = be32_to_cpup(ranges++);
ret = uniphier_system_bus_add_bank(priv, bank, addr,
paddr, size);
if (ret)
return ret;
}
ret = uniphier_system_bus_check_overlap(priv);
if (ret)
return ret;
uniphier_system_bus_check_boot_swap(priv);
uniphier_system_bus_set_reg(priv);
/* Now, the bus is configured. Populate platform_devices below it */
return of_platform_default_populate(dev->of_node, NULL, dev);
}
static const struct of_device_id uniphier_system_bus_match[] = {
{ .compatible = "socionext,uniphier-system-bus" },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, uniphier_system_bus_match);
static struct platform_driver uniphier_system_bus_driver = {
.probe = uniphier_system_bus_probe,
.driver = {
.name = "uniphier-system-bus",
.of_match_table = uniphier_system_bus_match,
},
};
module_platform_driver(uniphier_system_bus_driver);
MODULE_AUTHOR("Masahiro Yamada <yamada.masahiro@socionext.com>");
MODULE_DESCRIPTION("UniPhier System Bus driver");
MODULE_LICENSE("GPL");