Hi Manivannan,
Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx> wrote on Thu,
25 Feb 2021 09:41:29 +0530:
> On a typical end product, a vendor may choose to secure some regions in
> the NAND memory which are supposed to stay intact between FW upgrades.
> The access to those regions will be blocked by a secure element like
> Trustzone. So the normal world software like Linux kernel should not
> touch these regions (including reading).
>
> The regions are declared using a NAND chip DT property,
> "nand-secure-regions". So let's make use of this property and skip
> access to the secure regions present in a system.
>
> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
> ---
[...]
> config_nand_page_write(nandc);
> @@ -2830,7 +2865,8 @@ static int qcom_nand_host_init_and_register(struct qcom_nand_controller *nandc,
> struct nand_chip *chip = &host->chip;
> struct mtd_info *mtd = nand_to_mtd(chip);
> struct device *dev = nandc->dev;
> - int ret;
> + struct property *prop;
> + int ret, length, nr_elem;
>
> ret = of_property_read_u32(dn, "reg", &host->cs);
> if (ret) {
> @@ -2886,6 +2922,24 @@ static int qcom_nand_host_init_and_register(struct qcom_nand_controller *nandc,
> }
> }
>
> + /*
> + * Look for secure regions in the NAND chip. These regions are supposed
> + * to be protected by a secure element like Trustzone. So the read/write
> + * accesses to these regions will be blocked in the runtime by this
> + * driver.
> + */
> + prop = of_find_property(dn, "nand-secure-regions", &length);
I'm not sure the nand- prefix on this property is needed here, but
whatever.
> + if (prop) {
> + nr_elem = length / sizeof(u32);
> + host->nr_sec_regions = nr_elem / 2;
> +
> + host->sec_regions = devm_kcalloc(dev, nr_elem, sizeof(u32), GFP_KERNEL);
> + if (!host->sec_regions)
> + return -ENOMEM;
> +
> + of_property_read_u32_array(dn, "nand-secure-regions", host->sec_regions, nr_elem);
> + }
> +
I would move this before nand_scan().
If you don't, you should bail out with a nand_cleanup() upon error.
> ret = mtd_device_parse_register(mtd, probes, NULL, NULL, 0);
> if (ret)
> nand_cleanup(chip);
Otherwise lgtm.
Thanks,
Miquèl
