Re: [PATCH 01/10] mtd: add driver for intel graphics non-volatile memory device

[Rodrigo Vivi <rodrigo.vivi@intel.com>]

On Tue, Oct 22, 2024 at 01:41:10PM +0300, Alexander Usyskin wrote:
> Add auxiliary driver for intel discrete graphics
> non-volatile memory device.
> 
> CC: Rodrigo Vivi <rodrigo.vivi@intel.com>
> CC: Lucas De Marchi <lucas.demarchi@intel.com>
> Co-developed-by: Tomas Winkler <tomasw@gmail.com>
> Signed-off-by: Tomas Winkler <tomasw@gmail.com>
> Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>

Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

> ---
>  MAINTAINERS                        |   7 ++
>  drivers/mtd/devices/Kconfig        |  11 +++
>  drivers/mtd/devices/Makefile       |   1 +
>  drivers/mtd/devices/mtd-intel-dg.c | 139 +++++++++++++++++++++++++++++
>  include/linux/intel_dg_nvm_aux.h   |  27 ++++++
>  5 files changed, 185 insertions(+)
>  create mode 100644 drivers/mtd/devices/mtd-intel-dg.c
>  create mode 100644 include/linux/intel_dg_nvm_aux.h
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index c27f3190737f..a09c035849ef 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -11360,6 +11360,13 @@ L:	linux-kernel@vger.kernel.org
>  S:	Supported
>  F:	arch/x86/include/asm/intel-family.h
>  
> +INTEL DISCRETE GRAPHIC NVM MTD DRIVER
> +M:	Alexander Usyskin <alexander.usyskin@intel.com>
> +L:	linux-mtd@lists.infradead.org
> +S:	Supported
> +F:	drivers/mtd/devices/mtd-intel-dg.c
> +F:	include/linux/intel_dg_nvm_aux.h
> +
>  INTEL DRM DISPLAY FOR XE AND I915 DRIVERS
>  M:	Jani Nikula <jani.nikula@linux.intel.com>
>  M:	Rodrigo Vivi <rodrigo.vivi@intel.com>
> diff --git a/drivers/mtd/devices/Kconfig b/drivers/mtd/devices/Kconfig
> index ff2f9e55ef28..d93edf45c0bb 100644
> --- a/drivers/mtd/devices/Kconfig
> +++ b/drivers/mtd/devices/Kconfig
> @@ -183,6 +183,17 @@ config MTD_POWERNV_FLASH
>  	  platforms from Linux. This device abstracts away the
>  	  firmware interface for flash access.
>  
> +config MTD_INTEL_DG
> +	tristate "Intel Discrete Graphic non-volatile memory driver"
> +	depends on AUXILIARY_BUS
> +	depends on MTD
> +	help
> +	  This provides MTD device to access Intel Discrete Graphic
> +	  non-volatile memory.
> +
> +	  To compile this driver as a module, choose M here: the module
> +	  will be called mtd-intel-dg.
> +
>  comment "Disk-On-Chip Device Drivers"
>  
>  config MTD_DOCG3
> diff --git a/drivers/mtd/devices/Makefile b/drivers/mtd/devices/Makefile
> index d11eb2b8b6f8..77c05d269034 100644
> --- a/drivers/mtd/devices/Makefile
> +++ b/drivers/mtd/devices/Makefile
> @@ -18,6 +18,7 @@ obj-$(CONFIG_MTD_SST25L)	+= sst25l.o
>  obj-$(CONFIG_MTD_BCM47XXSFLASH)	+= bcm47xxsflash.o
>  obj-$(CONFIG_MTD_ST_SPI_FSM)    += st_spi_fsm.o
>  obj-$(CONFIG_MTD_POWERNV_FLASH)	+= powernv_flash.o
> +obj-$(CONFIG_MTD_INTEL_DG)	+= mtd-intel-dg.o
>  
>  
>  CFLAGS_docg3.o			+= -I$(src)
> diff --git a/drivers/mtd/devices/mtd-intel-dg.c b/drivers/mtd/devices/mtd-intel-dg.c
> new file mode 100644
> index 000000000000..746c963ea540
> --- /dev/null
> +++ b/drivers/mtd/devices/mtd-intel-dg.c
> @@ -0,0 +1,139 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright(c) 2019-2024, Intel Corporation. All rights reserved.
> + */
> +
> +#include <linux/device.h>
> +#include <linux/intel_dg_nvm_aux.h>
> +#include <linux/io.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/string.h>
> +#include <linux/slab.h>
> +#include <linux/types.h>
> +
> +struct intel_dg_nvm {
> +	struct kref refcnt;
> +	void __iomem *base;
> +	size_t size;
> +	unsigned int nregions;
> +	struct {
> +		const char *name;
> +		u8 id;
> +		u64 offset;
> +		u64 size;
> +	} regions[];
> +};
> +
> +static void intel_dg_nvm_release(struct kref *kref)
> +{
> +	struct intel_dg_nvm *nvm = container_of(kref, struct intel_dg_nvm, refcnt);
> +	int i;
> +
> +	pr_debug("freeing intel_dg nvm\n");
> +	for (i = 0; i < nvm->nregions; i++)
> +		kfree(nvm->regions[i].name);
> +	kfree(nvm);
> +}
> +
> +static int intel_dg_mtd_probe(struct auxiliary_device *aux_dev,
> +			      const struct auxiliary_device_id *aux_dev_id)
> +{
> +	struct intel_dg_nvm_dev *invm = auxiliary_dev_to_intel_dg_nvm_dev(aux_dev);
> +	struct device *device;
> +	struct intel_dg_nvm *nvm;
> +	unsigned int nregions;
> +	unsigned int i, n;
> +	size_t size;
> +	char *name;
> +	int ret;
> +
> +	device = &aux_dev->dev;
> +
> +	/* count available regions */
> +	for (nregions = 0, i = 0; i < INTEL_DG_NVM_REGIONS; i++) {
> +		if (invm->regions[i].name)
> +			nregions++;
> +	}
> +
> +	if (!nregions) {
> +		dev_err(device, "no regions defined\n");
> +		return -ENODEV;
> +	}
> +
> +	size = sizeof(*nvm) + sizeof(nvm->regions[0]) * nregions;
> +	nvm = kzalloc(size, GFP_KERNEL);
> +	if (!nvm)
> +		return -ENOMEM;
> +
> +	kref_init(&nvm->refcnt);
> +
> +	nvm->nregions = nregions;
> +	for (n = 0, i = 0; i < INTEL_DG_NVM_REGIONS; i++) {
> +		if (!invm->regions[i].name)
> +			continue;
> +
> +		name = kasprintf(GFP_KERNEL, "%s.%s",
> +				 dev_name(&aux_dev->dev), invm->regions[i].name);
> +		if (!name)
> +			continue;
> +		nvm->regions[n].name = name;
> +		nvm->regions[n].id = i;
> +		n++;
> +	}
> +
> +	nvm->base = devm_ioremap_resource(device, &invm->bar);
> +	if (IS_ERR(nvm->base)) {
> +		dev_err(device, "mmio not mapped\n");
> +		ret = PTR_ERR(nvm->base);
> +		goto err;
> +	}
> +
> +	dev_set_drvdata(&aux_dev->dev, nvm);
> +
> +	return 0;
> +
> +err:
> +	kref_put(&nvm->refcnt, intel_dg_nvm_release);
> +	return ret;
> +}
> +
> +static void intel_dg_mtd_remove(struct auxiliary_device *aux_dev)
> +{
> +	struct intel_dg_nvm *nvm = dev_get_drvdata(&aux_dev->dev);
> +
> +	if (!nvm)
> +		return;
> +
> +	dev_set_drvdata(&aux_dev->dev, NULL);
> +
> +	kref_put(&nvm->refcnt, intel_dg_nvm_release);
> +}
> +
> +static const struct auxiliary_device_id intel_dg_mtd_id_table[] = {
> +	{
> +		.name = "i915.nvm",
> +	},
> +	{
> +		.name = "xe.nvm",
> +	},
> +	{
> +		/* sentinel */
> +	}
> +};
> +MODULE_DEVICE_TABLE(auxiliary, intel_dg_mtd_id_table);
> +
> +static struct auxiliary_driver intel_dg_mtd_driver = {
> +	.probe  = intel_dg_mtd_probe,
> +	.remove = intel_dg_mtd_remove,
> +	.driver = {
> +		/* auxiliary_driver_register() sets .name to be the modname */
> +	},
> +	.id_table = intel_dg_mtd_id_table
> +};
> +
> +module_auxiliary_driver(intel_dg_mtd_driver);
> +
> +MODULE_LICENSE("GPL");
> +MODULE_AUTHOR("Intel Corporation");
> +MODULE_DESCRIPTION("Intel DGFX MTD driver");
> diff --git a/include/linux/intel_dg_nvm_aux.h b/include/linux/intel_dg_nvm_aux.h
> new file mode 100644
> index 000000000000..2cc4179fbde2
> --- /dev/null
> +++ b/include/linux/intel_dg_nvm_aux.h
> @@ -0,0 +1,27 @@
> +/* SPDX-License-Identifier: MIT */
> +/*
> + * Copyright(c) 2019-2024, Intel Corporation. All rights reserved.
> + */
> +
> +#ifndef __INTEL_DG_NVM_AUX_H__
> +#define __INTEL_DG_NVM_AUX_H__
> +
> +#include <linux/auxiliary_bus.h>
> +
> +#define INTEL_DG_NVM_REGIONS 13
> +
> +struct intel_dg_nvm_region {
> +	const char *name;
> +};
> +
> +struct intel_dg_nvm_dev {
> +	struct auxiliary_device aux_dev;
> +	bool writeable_override;
> +	struct resource bar;
> +	const struct intel_dg_nvm_region *regions;
> +};
> +
> +#define auxiliary_dev_to_intel_dg_nvm_dev(auxiliary_dev) \
> +	container_of(auxiliary_dev, struct intel_dg_nvm_dev, aux_dev)
> +
> +#endif /* __INTEL_DG_NVM_AUX_H__ */
> -- 
> 2.43.0
>