mtd: add driver for intel graphics non-volatile memory device

Add auxiliary driver for intel discrete graphics
non-volatile memory device.

CC: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Raag Jadav <raag.jadav@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Acked-by: Miquel Raynal <miquel.raynal@bootlin.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>
Link: https://lore.kernel.org/r/20250617145159.3803852-2-alexander.usyskin@intel.com
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

diff --git a/MAINTAINERS b/MAINTAINERS
index 7e7515a412e9df5d94b5852a6f1c639995dfcc36..521730530243fb61e084caacdaa76c9f77a938de 100644 (file)
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -12086,6 +12086,13 @@ L:     linux-kernel@vger.kernel.org
 S:     Supported
 F:     arch/x86/include/asm/intel-family.h
 
+INTEL DISCRETE GRAPHICS 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 aed653ce8fa226e7d699128c9f9449a55b3f8b97..46cebde79f34b0b7fd121323151f2c0b54a7b6ea 100644 (file)
--- 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 Graphics non-volatile memory driver"
+       depends on AUXILIARY_BUS
+       depends on MTD
+       help
+         This provides an MTD device to access Intel Discrete Graphics
+         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 d11eb2b8b6f85ca383d5bcb59ca51725d3102cec..9fe4ce9cffde939b1b8a92275e10d87a107cdc9a 100644 (file)
--- 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 (file)
index 0000000..c2d0dbf
--- /dev/null
+++ b/drivers/mtd/devices/mtd_intel_dg.c
@@ -0,0 +1,134 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright(c) 2019-2025, 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[] __counted_by(nregions);
+};
+
+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 intel_dg_nvm *nvm;
+       struct device *device;
+       unsigned int nregions;
+       unsigned int i, n;
+       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;
+       }
+
+       nvm = kzalloc(struct_size(nvm, regions, nregions), GFP_KERNEL);
+       if (!nvm)
+               return -ENOMEM;
+
+       kref_init(&nvm->refcnt);
+
+       for (n = 0, i = 0; i < INTEL_DG_NVM_REGIONS; i++) {
+               if (!invm->regions[i].name)
+                       continue;
+
+               char *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->nregions = n; /* in case where kasprintf fail */
+
+       nvm->base = devm_ioremap_resource(device, &invm->bar);
+       if (IS_ERR(nvm->base)) {
+               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 (file)
index 0000000..00b6c13
--- /dev/null
+++ b/include/linux/intel_dg_nvm_aux.h
@@ -0,0 +1,30 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright(c) 2019-2025, Intel Corporation. All rights reserved.
+ */
+
+#ifndef __INTEL_DG_NVM_AUX_H__
+#define __INTEL_DG_NVM_AUX_H__
+
+#include <linux/auxiliary_bus.h>
+#include <linux/container_of.h>
+#include <linux/ioport.h>
+#include <linux/types.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 writable_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__ */