> Subject: Re: [PATCH v9 02/12] mtd: add driver for intel graphics non-volatile
> memory device
>
> On Thu, Apr 24, 2025 at 04:25:26PM +0300, Alexander Usyskin wrote:
> > Add auxiliary driver for intel discrete graphics
> > non-volatile memory device.
>
> ...
>
> > +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;
>
> Perhaps move this to the loop it is being used in?
>
Will do
> > + 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;
>
> Is this assignment useful?
Nope, removing
>
> > + 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 */
>
> Considering kasprintf failure, should we move forward if n == 0?
Not sure if adding exit path here adds something positive to driver
other than complexity.
>
> > + nvm->base = devm_ioremap_resource(device, &invm->bar);
> > + if (IS_ERR(nvm->base)) {
> > + dev_err(device, "mmio not mapped\n");
>
> Is this useful? Perhaps the helper already does it for us.
Yes, will remove
>
> > + 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;
>
> Are we expecting this?
>
> > + dev_set_drvdata(&aux_dev->dev, NULL);
>
> Do we need this?
Is there guaranty by auxiliary device that after release nothing is called?
>
> > + 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
> > +};
>
> > +
>
> Nit: Redundant blank line.
Will remove
>
> > +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>
>
> Missing types.h, container_of.h
Will add
>
> > +#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
> >
