[v11] block: Add n64 cart driver

Message ID	20210123095327.58e5ab6c05f38e9080a79bd3@gmx.com (mailing list archive)
State	Not Applicable
Headers	show Return-Path: <linux-mips-owner@kernel.org> Date: Sat, 23 Jan 2021 09:53:27 +0200 From: Lauri Kasanen <cand@gmx.com> To: linux-mips@vger.kernel.org Cc: tsbogend@alpha.franken.de, axboe@kernel.dk, linux-block@vger.kernel.org, Keith Busch <kbusch@kernel.org>, Christoph Hellwig <hch@infradead.org> Subject: [PATCH v11] block: Add n64 cart driver Message-Id: <20210123095327.58e5ab6c05f38e9080a79bd3@gmx.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable Precedence: bulk
Series	[v11] block: Add n64 cart driver \| expand [v11] block: Add n64 cart driver

diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig index ecceaaa..924d768 100644 --- a/drivers/block/Kconfig +++ b/drivers/block/Kconfig @@ -72,6 +72,12 @@ config AMIGA_Z2RAM To compile this driver as a module, choose M here: the module will be called z2ram. +config N64CART + bool "N64 cart support" + depends on MACH_NINTENDO64 + help + Support for the N64 cart. + config CDROM tristate select BLK_SCSI_REQUEST diff --git a/drivers/block/Makefile b/drivers/block/Makefile index e1f6311..b9642cf 100644 --- a/drivers/block/Makefile +++ b/drivers/block/Makefile @@ -17,6 +17,7 @@ obj-$(CONFIG_PS3_DISK) += ps3disk.o obj-$(CONFIG_PS3_VRAM) += ps3vram.o obj-$(CONFIG_ATARI_FLOPPY) += ataflop.o obj-$(CONFIG_AMIGA_Z2RAM) += z2ram.o +obj-$(CONFIG_N64CART) += n64cart.o obj-$(CONFIG_BLK_DEV_RAM) += brd.o obj-$(CONFIG_BLK_DEV_LOOP) += loop.o obj-$(CONFIG_XILINX_SYSACE) += xsysace.o diff --git a/drivers/block/n64cart.c b/drivers/block/n64cart.c new file mode 100644 index 0000000..e76722a --- /dev/null +++ b/drivers/block/n64cart.c @@ -0,0 +1,189 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Support for the N64 cart. + * + * Copyright (c) 2021 Lauri Kasanen + */ + +#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> + +MODULE_AUTHOR("Lauri Kasanen <cand@gmx.com>"); +MODULE_DESCRIPTION("Driver for the N64 cart"); +MODULE_LICENSE("GPL"); + +static unsigned int start, size; +static u32 __iomem *reg_base; +static struct device *dev; + +#define PI_DRAM_REG 0 +#define PI_CART_REG 1 +#define PI_READ_REG 2 +#define PI_WRITE_REG 3 +#define PI_STATUS_REG 4 + +#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 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; + u32 pos; + struct bvec_iter iter; + + 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) +{ + int err; + struct request_queue *queue; + struct gendisk *disk; + + if (!start || !size) { + pr_err("n64cart: start and size not specified\n"); + return -ENODEV; + } + + if (size & 4095) { + pr_err("n64cart: size must be a multiple of 4K\n"); + return -ENODEV; + } + + queue = blk_alloc_queue(NUMA_NO_NODE); + if (!queue) { + return -ENOMEM; + } + + reg_base = devm_platform_ioremap_resource(pdev, 0); + if (!reg_base) { + err = -EINVAL; + goto fail_queue; + } + + disk = alloc_disk(0); + if (!disk) { + err = -ENOMEM; + goto fail_queue; + } + + dev = &pdev->dev; + + disk->first_minor = 0; + disk->queue = queue; + disk->flags = GENHD_FL_NO_PART_SCAN | GENHD_FL_EXT_DEVT; + disk->fops = &n64cart_fops; + strcpy(disk->disk_name, "n64cart"); + + set_capacity(disk, size / 512); + set_disk_ro(disk, 1); + + blk_queue_flag_set(QUEUE_FLAG_NONROT, queue); + blk_queue_physical_block_size(queue, 4096); + blk_queue_logical_block_size(queue, 4096); + + add_disk(disk); + + pr_info("n64cart: %u kb disk\n", size / 1024); + + return 0; +fail_queue: + blk_cleanup_queue(queue); + + return err; +} + +static struct platform_driver n64cart_driver = { + .driver = { + .name = "n64cart", + }, +}; + +static int __init n64cart_init(void) +{ + return platform_driver_probe(&n64cart_driver, n64cart_probe); +} + +module_param(start, uint, 0); +MODULE_PARM_DESC(start, "Start address of the cart block data"); + +module_param(size, uint, 0); +MODULE_PARM_DESC(size, "Size of the cart block data, in bytes"); + +module_init(n64cart_init);

[v11] block: Add n64 cart driver

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