Re: [PATCH v5 2/2] nvmem: sec-qfprom: Add Qualcomm secure QFPROM support

[Komal Bajaj]

On 7/28/2023 1:55 PM, Mukesh Ojha wrote:
> On 7/27/2023 4:14 PM, Srinivas Kandagatla wrote:
> > On 24/07/2023 09:38, Komal Bajaj wrote:
> > > For some of the Qualcomm SoC's, it is possible that
> > > some of the fuse regions or entire qfprom region is
> > > protected from non-secure access. In such situations,
> > > Linux will have to use secure calls to read the region.
> > > With that motivation, add secure qfprom driver.
> > >
> > > Signed-off-by: Komal Bajaj <quic_kbajaj@xxxxxxxxxxx>
> > > ---
> > >   drivers/nvmem/Kconfig      |  13 +++++
> > >   drivers/nvmem/Makefile     |   2 +
> > >   drivers/nvmem/sec-qfprom.c | 101 
> > > +++++++++++++++++++++++++++++++++++++
> > >   3 files changed, 116 insertions(+)
> > >   create mode 100644 drivers/nvmem/sec-qfprom.c
> >
> > > diff --git a/drivers/nvmem/sec-qfprom.c b/drivers/nvmem/sec-qfprom.c
> > > new file mode 100644
> > > index 000000000000..bc68053b7d94
> > > --- /dev/null
> > > +++ b/drivers/nvmem/sec-qfprom.c
> > > @@ -0,0 +1,101 @@
> > > +// SPDX-License-Identifier: GPL-2.0-only
> > > +/*
> > > + * Copyright (c) 2023, Qualcomm Innovation Center, Inc. All rights 
> > > reserved.
> > > + */
> > > +
> > > +#include <linux/firmware/qcom/qcom_scm.h>
> > > +#include <linux/mod_devicetable.h>
> > > +#include <linux/nvmem-provider.h>
> > > +#include <linux/platform_device.h>
> > > +#include <linux/pm_runtime.h>
> >
> > > +
> > > +static int sec_qfprom_probe(struct platform_device *pdev)
> > > +{
> > > +    struct nvmem_config econfig = {
> > > +        .name = "sec-qfprom",
> > > +        .stride = 1,
> > > +        .word_size = 1,
> > > +        .id = NVMEM_DEVID_AUTO,
> > > +        .reg_read = sec_qfprom_reg_read,
> > > +    };
> > > +    struct device *dev = &pdev->dev;
> > > +    struct nvmem_device *nvmem;
> > > +    struct sec_qfprom *priv;
> > > +    struct resource *res;
> > > +    int ret;
> > > +
> > > +    priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> > > +    if (!priv)
> > > +        return -ENOMEM;
> > > +
> > > +    res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > > +    if (!res)
> > > +        return -EINVAL;
> > > +
> > > +    priv->base = res->start;
> > > +
> > > +    econfig.size = resource_size(res);
> > > +    econfig.dev = dev;
> > > +    econfig.priv = priv;
> > > +
> > > +    priv->dev = dev;
> > > +
> > > +    ret = devm_pm_runtime_enable(dev);
> > > +    if (ret)
> > > +        return ret;
> >
> > Any reason why we need to enable pm runtime for this driver? As Am 
> > not seeing any pm runtime handlers or users in this driver.
>
> Thanks..
> Yes, it is not needed as of now..
> looks like, it got inherited from qfprom.c by mistake.
>
> Same need to be corrected in Device tree, if any
> unnecessary reference is there related to this..

Thanks for pointing it out.
Will drop it in the next patch series.

Thanks
Komal

> -Mukesh
> > --srini
> > > +
> > > +    nvmem = devm_nvmem_register(dev, &econfig);
> > > +
> > > +    return PTR_ERR_OR_ZERO(nvmem);
> > > +}
> > > +
> > > +static const struct of_device_id sec_qfprom_of_match[] = {
> > > +    { .compatible = "qcom,sec-qfprom" },
> > > +    {/* sentinel */},
> > > +};
> > > +MODULE_DEVICE_TABLE(of, sec_qfprom_of_match);
> > > +
> > > +static struct platform_driver qfprom_driver = {
> > > +    .probe = sec_qfprom_probe,
> > > +    .driver = {
> > > +        .name = "qcom_sec_qfprom",
> > > +        .of_match_table = sec_qfprom_of_match,
> > > +    },
> > > +};
> > > +module_platform_driver(qfprom_driver);
> > > +MODULE_DESCRIPTION("Qualcomm Secure QFPROM driver");
> > > +MODULE_LICENSE("GPL");
> > > --
> > > 2.40.1