diff mbox series

[v11] block: Add n64 cart driver

Message ID 20210123095327.58e5ab6c05f38e9080a79bd3@gmx.com (mailing list archive)
State New, archived
Headers show
Series [v11] block: Add n64 cart driver | expand

Commit Message

Lauri Kasanen Jan. 23, 2021, 7:53 a.m. UTC
This adds support for the Nintendo 64 console's carts. Carts are a
read-only media ranging from 8mb to 64mb.

Only one cart can be connected at once, and switching it requires a
reboot.

No module support to save RAM, as the target has 8mb RAM.

Signed-off-by: Lauri Kasanen <cand@gmx.com>
---
 drivers/block/Kconfig   |   6 ++
 drivers/block/Makefile  |   1 +
 drivers/block/n64cart.c | 189 ++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 196 insertions(+)
 create mode 100644 drivers/block/n64cart.c

v11:
bool n64cart_do_bvec
remove bio_end_sector() > get_capacity() check
pass bvec to helper, remove some local vars

v10:
convert to bio
DMA directly to the bio buffer

v9:
cosmetics
min_t

v8:
SZ_64K
remove barriers
add defines for block domain constants
__blk_mq_end_request
remove register_blkdev via GENHD_FL_EXT_DEVT
dma_alloc_noncoherent, sync

--
2.6.2

Comments

Christoph Hellwig Jan. 23, 2021, 12:42 p.m. UTC | #1
Looks good,

Reviewed-by: Christoph Hellwig <hch@lst.de>
Chaitanya Kulkarni Jan. 25, 2021, 11:16 p.m. UTC | #2
On 1/22/21 23:55, Lauri Kasanen wrote:
> This adds support for the Nintendo 64 console's carts. Carts are a
> read-only media ranging from 8mb to 64mb.
>
> Only one cart can be connected at once, and switching it requires a
> reboot.
>
> No module support to save RAM, as the target has 8mb RAM.
>
> Signed-off-by: Lauri Kasanen <cand@gmx.com>
>
Looks good.

Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Lauri Kasanen Feb. 6, 2021, 5:28 p.m. UTC | #3
On Sat, 23 Jan 2021 12:42:10 +0000
Christoph Hellwig <hch@infradead.org> wrote:

> Looks good,
>
> Reviewed-by: Christoph Hellwig <hch@lst.de>

Hi,

Ping on this patch. Thomas, do you want to pick it up?

- Lauri
Chaitanya Kulkarni Feb. 8, 2021, 6:39 a.m. UTC | #4
On 2/6/21 09:31, Lauri Kasanen wrote:
> On Sat, 23 Jan 2021 12:42:10 +0000
> Christoph Hellwig <hch@infradead.org> wrote:
>
>> Looks good,
>>
>> Reviewed-by: Christoph Hellwig <hch@lst.de>
> Hi,
>
> Ping on this patch. Thomas, do you want to pick it up?
>
> - Lauri
>

Whoever is going to apply this patch please apply following series on the
top of this one :-

https://www.spinics.net/lists/linux-mips/msg03296.html
Thomas Bogendoerfer Feb. 11, 2021, 10:23 a.m. UTC | #5
On Sat, Feb 06, 2021 at 07:28:37PM +0200, Lauri Kasanen wrote:
> On Sat, 23 Jan 2021 12:42:10 +0000
> Christoph Hellwig <hch@infradead.org> wrote:
> 
> > Looks good,
> >
> > Reviewed-by: Christoph Hellwig <hch@lst.de>
> 
> Hi,
> 
> Ping on this patch. Thomas, do you want to pick it up?

well that's up to the block maintainer. I'm open to take it
trhough mips-next, but then I need an acked-by for it.

Thomas.
Lauri Kasanen Feb. 21, 2021, 6:54 a.m. UTC | #6
On Thu, 11 Feb 2021 11:23:14 +0100
Thomas Bogendoerfer <tsbogend@alpha.franken.de> wrote:

> On Sat, Feb 06, 2021 at 07:28:37PM +0200, Lauri Kasanen wrote:
> > On Sat, 23 Jan 2021 12:42:10 +0000
> > Christoph Hellwig <hch@infradead.org> wrote:
> >
> > > Looks good,
> > >
> > > Reviewed-by: Christoph Hellwig <hch@lst.de>
> >
> > Hi,
> >
> > Ping on this patch. Thomas, do you want to pick it up?
>
> well that's up to the block maintainer. I'm open to take it
> trhough mips-next, but then I need an acked-by for it.

Hi,

Ping 2. Jens, I know you're busy, but just a mention this is on your
TODO list would be fine.

- Lauri
Jens Axboe Feb. 21, 2021, 1:13 p.m. UTC | #7
On 2/20/21 11:54 PM, Lauri Kasanen wrote:
> On Thu, 11 Feb 2021 11:23:14 +0100
> Thomas Bogendoerfer <tsbogend@alpha.franken.de> wrote:
> 
>> On Sat, Feb 06, 2021 at 07:28:37PM +0200, Lauri Kasanen wrote:
>>> On Sat, 23 Jan 2021 12:42:10 +0000
>>> Christoph Hellwig <hch@infradead.org> wrote:
>>>
>>>> Looks good,
>>>>
>>>> Reviewed-by: Christoph Hellwig <hch@lst.de>
>>>
>>> Hi,
>>>
>>> Ping on this patch. Thomas, do you want to pick it up?
>>
>> well that's up to the block maintainer. I'm open to take it
>> trhough mips-next, but then I need an acked-by for it.
> 
> Hi,
> 
> Ping 2. Jens, I know you're busy, but just a mention this is on your
> TODO list would be fine.

That's fine, you can add my acked-by to the driver.
Thomas Bogendoerfer Feb. 21, 2021, 10:39 p.m. UTC | #8
On Sat, Jan 23, 2021 at 09:53:27AM +0200, Lauri Kasanen wrote:
> This adds support for the Nintendo 64 console's carts. Carts are a
> read-only media ranging from 8mb to 64mb.
> 
> Only one cart can be connected at once, and switching it requires a
> reboot.
> 
> No module support to save RAM, as the target has 8mb RAM.
> 
> Signed-off-by: Lauri Kasanen <cand@gmx.com>
> ---
>  drivers/block/Kconfig   |   6 ++
>  drivers/block/Makefile  |   1 +
>  drivers/block/n64cart.c | 189 ++++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 196 insertions(+)
>  create mode 100644 drivers/block/n64cart.c

applied to mips-next.

Thomas.
diff mbox series

Patch

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);