forked from torvalds/linux
-
Notifications
You must be signed in to change notification settings - Fork 0
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
Merge tag 'mips_5.12_1' of git://git.kernel.org/pub/scm/linux/kernel/…
…git/mips/linux Pull more MIPS updates from Thomas Bogendoerfer: - added n64 block driver - fix for ubsan warnings - fix for bcm63xx platform - update of linux-mips mailinglist * tag 'mips_5.12_1' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux: arch: mips: update references to current linux-mips list mips: bmips: init clocks earlier vmlinux.lds.h: catch even more instrumentation symbols into .data n64: store dev instance into disk private data n64: cleanup n64cart_probe() n64: cosmetics changes n64: remove curly brackets n64: use sector SECTOR_SHIFT instead 512 n64: use enums for reg n64: move module param at the top n64: move module info at the end n64: use pr_fmt to avoid duplicate string block: Add n64 cart driver
- Loading branch information
Showing
8 changed files
with
190 additions
and
5 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,178 @@ | ||
// SPDX-License-Identifier: GPL-2.0 | ||
/* | ||
* Support for the N64 cart. | ||
* | ||
* Copyright (c) 2021 Lauri Kasanen | ||
*/ | ||
|
||
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt | ||
#include <linux/bitops.h> | ||
#include <linux/blkdev.h> | ||
#include <linux/dma-mapping.h> | ||
#include <linux/init.h> | ||
#include <linux/module.h> | ||
#include <linux/platform_device.h> | ||
|
||
enum { | ||
PI_DRAM_REG = 0, | ||
PI_CART_REG, | ||
PI_READ_REG, | ||
PI_WRITE_REG, | ||
PI_STATUS_REG, | ||
}; | ||
|
||
#define PI_STATUS_DMA_BUSY (1 << 0) | ||
#define PI_STATUS_IO_BUSY (1 << 1) | ||
|
||
#define CART_DOMAIN 0x10000000 | ||
#define CART_MAX 0x1FFFFFFF | ||
|
||
#define MIN_ALIGNMENT 8 | ||
|
||
static u32 __iomem *reg_base; | ||
|
||
static unsigned int start; | ||
module_param(start, uint, 0); | ||
MODULE_PARM_DESC(start, "Start address of the cart block data"); | ||
|
||
static unsigned int size; | ||
module_param(size, uint, 0); | ||
MODULE_PARM_DESC(size, "Size of the cart block data, in bytes"); | ||
|
||
static void n64cart_write_reg(const u8 reg, const u32 value) | ||
{ | ||
writel(value, reg_base + reg); | ||
} | ||
|
||
static u32 n64cart_read_reg(const u8 reg) | ||
{ | ||
return readl(reg_base + reg); | ||
} | ||
|
||
static void n64cart_wait_dma(void) | ||
{ | ||
while (n64cart_read_reg(PI_STATUS_REG) & | ||
(PI_STATUS_DMA_BUSY | PI_STATUS_IO_BUSY)) | ||
cpu_relax(); | ||
} | ||
|
||
/* | ||
* Process a single bvec of a bio. | ||
*/ | ||
static bool n64cart_do_bvec(struct device *dev, struct bio_vec *bv, u32 pos) | ||
{ | ||
dma_addr_t dma_addr; | ||
const u32 bstart = pos + start; | ||
|
||
/* Alignment check */ | ||
WARN_ON_ONCE((bv->bv_offset & (MIN_ALIGNMENT - 1)) || | ||
(bv->bv_len & (MIN_ALIGNMENT - 1))); | ||
|
||
dma_addr = dma_map_bvec(dev, bv, DMA_FROM_DEVICE, 0); | ||
if (dma_mapping_error(dev, dma_addr)) | ||
return false; | ||
|
||
n64cart_wait_dma(); | ||
|
||
n64cart_write_reg(PI_DRAM_REG, dma_addr + bv->bv_offset); | ||
n64cart_write_reg(PI_CART_REG, (bstart | CART_DOMAIN) & CART_MAX); | ||
n64cart_write_reg(PI_WRITE_REG, bv->bv_len - 1); | ||
|
||
n64cart_wait_dma(); | ||
|
||
dma_unmap_page(dev, dma_addr, bv->bv_len, DMA_FROM_DEVICE); | ||
return true; | ||
} | ||
|
||
static blk_qc_t n64cart_submit_bio(struct bio *bio) | ||
{ | ||
struct bio_vec bvec; | ||
struct bvec_iter iter; | ||
struct device *dev = bio->bi_disk->private_data; | ||
u32 pos = bio->bi_iter.bi_sector << SECTOR_SHIFT; | ||
|
||
bio_for_each_segment(bvec, bio, iter) { | ||
if (!n64cart_do_bvec(dev, &bvec, pos)) | ||
goto io_error; | ||
pos += bvec.bv_len; | ||
} | ||
|
||
bio_endio(bio); | ||
return BLK_QC_T_NONE; | ||
io_error: | ||
bio_io_error(bio); | ||
return BLK_QC_T_NONE; | ||
} | ||
|
||
static const struct block_device_operations n64cart_fops = { | ||
.owner = THIS_MODULE, | ||
.submit_bio = n64cart_submit_bio, | ||
}; | ||
|
||
/* | ||
* The target device is embedded and RAM-constrained. We save RAM | ||
* by initializing in __init code that gets dropped late in boot. | ||
* For the same reason there is no module or unloading support. | ||
*/ | ||
static int __init n64cart_probe(struct platform_device *pdev) | ||
{ | ||
struct gendisk *disk; | ||
|
||
if (!start || !size) { | ||
pr_err("start or size not specified\n"); | ||
return -ENODEV; | ||
} | ||
|
||
if (size & 4095) { | ||
pr_err("size must be a multiple of 4K\n"); | ||
return -ENODEV; | ||
} | ||
|
||
reg_base = devm_platform_ioremap_resource(pdev, 0); | ||
if (!reg_base) | ||
return -EINVAL; | ||
|
||
disk = alloc_disk(0); | ||
if (!disk) | ||
return -ENOMEM; | ||
|
||
disk->queue = blk_alloc_queue(NUMA_NO_NODE); | ||
if (!disk->queue) | ||
return -ENOMEM; | ||
|
||
disk->first_minor = 0; | ||
disk->flags = GENHD_FL_NO_PART_SCAN | GENHD_FL_EXT_DEVT; | ||
disk->fops = &n64cart_fops; | ||
disk->private_data = &pdev->dev; | ||
strcpy(disk->disk_name, "n64cart"); | ||
|
||
set_capacity(disk, size >> SECTOR_SHIFT); | ||
set_disk_ro(disk, 1); | ||
|
||
blk_queue_flag_set(QUEUE_FLAG_NONROT, disk->queue); | ||
blk_queue_physical_block_size(disk->queue, 4096); | ||
blk_queue_logical_block_size(disk->queue, 4096); | ||
|
||
add_disk(disk); | ||
|
||
pr_info("n64cart: %u kb disk\n", size / 1024); | ||
|
||
return 0; | ||
} | ||
|
||
static struct platform_driver n64cart_driver = { | ||
.driver = { | ||
.name = "n64cart", | ||
}, | ||
}; | ||
|
||
static int __init n64cart_init(void) | ||
{ | ||
return platform_driver_probe(&n64cart_driver, n64cart_probe); | ||
} | ||
|
||
module_init(n64cart_init); | ||
|
||
MODULE_AUTHOR("Lauri Kasanen <[email protected]>"); | ||
MODULE_DESCRIPTION("Driver for the N64 cart"); | ||
MODULE_LICENSE("GPL"); |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters