linux-kernel - Re: [PATCH v4 1/2] mtd: rawnand: Add support for Macronix NAND randomizer

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Date:   Fri, 17 Jan 2020 15:54:33 +0800
From:   masonccyang@...c.com.tw
To:     "Miquel Raynal" <miquel.raynal@...tlin.com>
Cc:     bbrezillon@...nel.org, computersforpeace@...il.com,
        devicetree@...r.kernel.org, dwmw2@...radead.org,
        juliensu@...c.com.tw, linux-kernel@...r.kernel.org,
        linux-mtd@...ts.infradead.org, marek.vasut@...il.com,
        mark.rutland@....com, richard@....at, robh+dt@...nel.org,
        vigneshr@...com
Subject: Re: [PATCH v4 1/2] mtd: rawnand: Add support for Macronix NAND randomizer


Hi Miquel,

 
> > +static int macronix_nand_randomizer_check_enable(struct nand_chip 
*chip)
> > +{
> > +   u8 feature[ONFI_SUBFEATURE_PARAM_LEN];
> > +   int ret;
> > +
> > +   ret = nand_get_features(chip, ONFI_FEATURE_ADDR_MXIC_RANDOMIZER,
> > +            feature);
> > +   if (ret < 0)
> > +      return ret;
> > +
> > +   if (feature[0])
> > +      return feature[0];
> > +
> > +   feature[0] = MACRONIX_RANDOMIZER_MODE_ENTER;
> > +   ret = nand_set_features(chip, ONFI_FEATURE_ADDR_MXIC_RANDOMIZER,
> > +            feature);
> > +   if (ret < 0)
> > +      return ret;
> > +
> > +   /* RANDEN and RANDOPT OTP bits are programmed */
> > +   feature[0] = 0x0;
> > +   ret = nand_prog_page_op(chip, 0, 0, feature, 1);
> > +   if (ret < 0)
> > +      return ret;
> > +
> > +   ret = nand_get_features(chip, ONFI_FEATURE_ADDR_MXIC_RANDOMIZER,
> > +            feature);
> > +   if (ret < 0)
> > +      return ret;
> > +
> > +   feature[0] &= MACRONIX_RANDOMIZER_MODE_EXIT;
> > +   ret = nand_set_features(chip, ONFI_FEATURE_ADDR_MXIC_RANDOMIZER,
> > +            feature);
> > +   if (ret < 0)
> > +      return ret;
> > +
> > +   return feature[0];
> 
> Can feature[0] be != 0 ? I don't think so, in this case I prefer a:
> return 0;
> 

okay, will fix it.

> > +}
> > +
> >  static void macronix_nand_onfi_init(struct nand_chip *chip)
> >  {
> >     struct nand_parameters *p = &chip->parameters;
> >     struct nand_onfi_vendor_macronix *mxic;
> > +   struct device_node *dn = nand_get_flash_node(chip);
> > +   int rand_otp = 0;
> > +   int ret;
> > 
> >     if (!p->onfi)
> >        return;
> > 
> > +   if (of_find_property(dn, "mxic,enable-randomizer-otp", NULL))
> > +      rand_otp = 1;
> > +
> >     mxic = (struct nand_onfi_vendor_macronix *)p->onfi->vendor;
> > +   /* Subpage write is prohibited in randomizer operatoin */
> 
>                                        with          operation
> 
> > +   if (rand_otp && chip->options & NAND_NO_SUBPAGE_WRITE &&
> > +       mxic->reliability_func & MACRONIX_RANDOMIZER_BIT) {
> > +      if (p->supports_set_get_features) {
> > +         bitmap_set(p->set_feature_list,
> > +               ONFI_FEATURE_ADDR_MXIC_RANDOMIZER, 1);
> > +         bitmap_set(p->get_feature_list,
> > +               ONFI_FEATURE_ADDR_MXIC_RANDOMIZER, 1);
> > +         ret = macronix_nand_randomizer_check_enable(chip);
> > +         if (ret < 0)
> > +            pr_info("Macronix NAND randomizer failed\n");
> > +         else
> > +            pr_info("Macronix NAND randomizer enabled\n");
> 
> Maybe we should update the bitmaps only if it succeeds?

okay, will drop pr_info();

> 
> > +      }
> > +   }
> > +
> >     if ((mxic->reliability_func & MACRONIX_READ_RETRY_BIT) == 0)
> >        return;
> > 
> 
> With the above fixed,
> Reviewed-by: Miquel Raynal <miquel.raynal@...tlin.com>
> 
> Thanks,
> Miquèl

thanks for your time & comments.
Mason

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CONFIDENTIALITY NOTE:

This e-mail and any attachments may contain confidential information and/or personal data, which is protected by applicable laws. Please be reminded that duplication, disclosure, distribution, or use of this e-mail (and/or its attachments) or any part thereof is prohibited. If you receive this e-mail in error, please notify us immediately and delete this mail as well as its attachment(s) from your system. In addition, please be informed that collection, processing, and/or use of personal data is prohibited unless expressly permitted by personal data protection laws. Thank you for your attention and cooperation.

Macronix International Co., Ltd.

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