Re: [PATCH 2/2] misc: Add devicetree SRAM driver

[Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>]

On 10:30 Wed 29 Jan     , Sascha Hauer wrote:
> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
> ---
>  drivers/misc/Kconfig  |  6 +++++
>  drivers/misc/Makefile |  1 +
>  drivers/misc/sram.c   | 75 +++++++++++++++++++++++++++++++++++++++++++++++++++

on at91 we already use the sram

and the sram could be used by any driver for dma (ethernet, framebuffer)

how could handle this in the generic driver?
>  3 files changed, 82 insertions(+)
>  create mode 100644 drivers/misc/sram.c
> 
> diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
> index e59c4f1..c34a4af 100644
> --- a/drivers/misc/Kconfig
> +++ b/drivers/misc/Kconfig
> @@ -9,4 +9,10 @@ config JTAG
>  	depends on GENERIC_GPIO
>  	help
>  	  Controls JTAG chains connected to I/O pins
> +
> +config SRAM
> +	bool "Generic SRAM driver"
> +	help
> +	  This driver adds support for memory mapped SRAM.
> +
>  endmenu
> diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
> index b085577..908c8cb 100644
> --- a/drivers/misc/Makefile
> +++ b/drivers/misc/Makefile
> @@ -3,3 +3,4 @@
>  #
>  
>  obj-$(CONFIG_JTAG)		+= jtag.o
> +obj-$(CONFIG_SRAM)		+= sram.o
> diff --git a/drivers/misc/sram.c b/drivers/misc/sram.c
> new file mode 100644
> index 0000000..7ea23b7
> --- /dev/null
> +++ b/drivers/misc/sram.c
> @@ -0,0 +1,75 @@
> +/*
> + * drivers/misc/sram.c - generic memory mapped SRAM driver
> + *
> + * 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 <common.h>
> +#include <errno.h>
> +#include <driver.h>
> +#include <malloc.h>
> +#include <init.h>
> +
> +struct sram {
> +	struct resource *res;
> +	char *name;
> +	struct cdev cdev;
> +};
> +
> +static struct file_operations memops = {
> +	.read  = mem_read,
> +	.write = mem_write,
> +	.memmap = generic_memmap_rw,
> +	.lseek = dev_lseek_default,
> +};
> +
> +static int sram_probe(struct device_d *dev)
> +{
> +	struct sram *sram;
> +	struct resource *res;
> +	void __iomem *base;
> +	int ret;
> +
> +	base = dev_request_mem_region(dev, 0);
> +	if (!base)
> +		return -EBUSY;
> +
> +	sram = xzalloc(sizeof(*sram));
> +
> +	sram->cdev.name = asprintf("sram%d",
> +			cdev_find_free_index("sram"));
> +
> +	res = dev_get_resource(dev, 0);
> +
> +	sram->cdev.size = (unsigned long)resource_size(res);
> +	sram->cdev.ops = &memops;
> +	sram->cdev.dev = dev;
> +
> +	ret = devfs_create(&sram->cdev);
> +	if (ret)
> +		return ret;
> +
> +	return 0;
> +}
> +
> +static __maybe_unused struct of_device_id sram_dt_ids[] = {
> +	{
> +		.compatible = "mmio-sram",
> +	}, {
> +	},
> +};
> +
> +static struct driver_d sram_driver = {
> +	.name = "mmio-sram",
> +	.probe = sram_probe,
> +	.of_compatible = sram_dt_ids,
> +};
> +device_platform_driver(sram_driver);
> -- 
> 1.8.5.3
> 
> 
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