[PATCH v6 02/11] mtd: add driver for intel graphics non-volatile memory device

Alexander Usyskin
2025-03-02T14:20:52Z

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

CC: Lucas De Marchi <lucas.demarchi@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>
---
MAINTAINERS | 7 ++
drivers/mtd/devices/Kconfig | 11 +++
drivers/mtd/devices/Makefile | 1 +
drivers/mtd/devices/mtd_intel_dg.c | 138 +++++++++++++++++++++++++++++
include/linux/intel_dg_nvm_aux.h | 27 ++++++
5 files changed, 184 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 cddcb097f7f3..ad29d54cc83f 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -11549,6 +11549,13 @@ 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 ff2f9e55ef28..59be6d3f0d32 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 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 d11eb2b8b6f8..9fe4ce9cffde 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..963a88cacc6c
--- /dev/null
+++ b/drivers/mtd/devices/mtd_intel_dg.c
@@ -0,0 +1,138 @@
+// 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 device *device;
+ struct intel_dg_nvm *nvm;
+ unsigned int nregions;
+ unsigned int i, n;
+ 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;
+ }
+
+ nvm = kzalloc(struct_size(nvm, regions, nregions), 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->nregions = n; /* in case where kasprintf fail */
+
+ 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..68df634c994c
--- /dev/null
+++ b/include/linux/intel_dg_nvm_aux.h
@@ -0,0 +1,27 @@
+/* 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>
+
+#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__ */
--
2.43.0