physically into the CPU's memory. The mapping description here is
taken from OF device tree.
-config MTD_PHYSMAP_BT1_ROM
- bool "Baikal-T1 Boot ROMs OF-based physical memory map handling"
- depends on MTD_PHYSMAP_OF
- depends on MIPS_BAIKAL_T1 || COMPILE_TEST
- select MTD_COMPLEX_MAPPINGS
- select MULTIPLEXER
- select MUX_MMIO
- help
- This provides some extra DT physmap parsing for the Baikal-T1
- platforms, some detection and setting up ROMs-specific accessors.
-
config MTD_PHYSMAP_VERSATILE
bool "ARM Versatile OF-based physical memory map handling"
depends on MTD_PHYSMAP_OF
+++ /dev/null
-// SPDX-License-Identifier: GPL-2.0-only
-/*
- * Copyright (C) 2020 BAIKAL ELECTRONICS, JSC
- *
- * Authors:
- * Serge Semin <Sergey.Semin@baikalelectronics.ru>
- *
- * Baikal-T1 Physically Mapped Internal ROM driver
- */
-#include <linux/bits.h>
-#include <linux/device.h>
-#include <linux/kernel.h>
-#include <linux/mtd/map.h>
-#include <linux/mtd/xip.h>
-#include <linux/mux/consumer.h>
-#include <linux/of.h>
-#include <linux/platform_device.h>
-#include <linux/string.h>
-#include <linux/types.h>
-
-#include "physmap-bt1-rom.h"
-
-/*
- * Baikal-T1 SoC ROMs are only accessible by the dword-aligned instructions.
- * We have to take this into account when implementing the data read-methods.
- * Note there is no need in bothering with endianness, since both Baikal-T1
- * CPU and MMIO are LE.
- */
-static map_word __xipram bt1_rom_map_read(struct map_info *map,
- unsigned long ofs)
-{
- void __iomem *src = map->virt + ofs;
- unsigned int shift;
- map_word ret;
- u32 data;
-
- /* Read data within offset dword. */
- shift = (uintptr_t)src & 0x3;
- data = readl_relaxed(src - shift);
- if (!shift) {
- ret.x[0] = data;
- return ret;
- }
- ret.x[0] = data >> (shift * BITS_PER_BYTE);
-
- /* Read data from the next dword. */
- shift = 4 - shift;
- if (ofs + shift >= map->size)
- return ret;
-
- data = readl_relaxed(src + shift);
- ret.x[0] |= data << (shift * BITS_PER_BYTE);
-
- return ret;
-}
-
-static void __xipram bt1_rom_map_copy_from(struct map_info *map,
- void *to, unsigned long from,
- ssize_t len)
-{
- void __iomem *src = map->virt + from;
- unsigned int shift, chunk;
- u32 data;
-
- if (len <= 0 || from >= map->size)
- return;
-
- /* Make sure we don't go over the map limit. */
- len = min_t(ssize_t, map->size - from, len);
-
- /*
- * Since requested data size can be pretty big we have to implement
- * the copy procedure as optimal as possible. That's why it's split
- * up into the next three stages: unaligned head, aligned body,
- * unaligned tail.
- */
- shift = (uintptr_t)src & 0x3;
- if (shift) {
- chunk = min_t(ssize_t, 4 - shift, len);
- data = readl_relaxed(src - shift);
- memcpy(to, (char *)&data + shift, chunk);
- src += chunk;
- to += chunk;
- len -= chunk;
- }
-
- while (len >= 4) {
- data = readl_relaxed(src);
- memcpy(to, &data, 4);
- src += 4;
- to += 4;
- len -= 4;
- }
-
- if (len) {
- data = readl_relaxed(src);
- memcpy(to, &data, len);
- }
-}
-
-int of_flash_probe_bt1_rom(struct platform_device *pdev,
- struct device_node *np,
- struct map_info *map)
-{
- struct device *dev = &pdev->dev;
-
- /* It's supposed to be read-only MTD. */
- if (!of_device_is_compatible(np, "mtd-rom")) {
- dev_info(dev, "No mtd-rom compatible string\n");
- return 0;
- }
-
- /* Multiplatform guard. */
- if (!of_device_is_compatible(np, "baikal,bt1-int-rom"))
- return 0;
-
- /* Sanity check the device parameters retrieved from DTB. */
- if (map->bankwidth != 4)
- dev_warn(dev, "Bank width is supposed to be 32 bits wide\n");
-
- map->read = bt1_rom_map_read;
- map->copy_from = bt1_rom_map_copy_from;
-
- return 0;
-}
projects / thirdparty / kernel / linux.git / commitdiff
