Re: [PATCH v2 0/9] mtd: spi-nor: parse SFDP tables to setup (Q)SPI memories

From: Jagan Teki
Date: Sat Oct 22 2016 - 07:00:47 EST

On Wed, Oct 5, 2016 at 5:30 PM, Cyrille Pitchen
<cyrille.pitchen@xxxxxxxxx> wrote:
> Hi all,
> This series extends support of SPI protocols to new protocols such as
> SPI x-2-2 and SPI x-4-4. Also spi_nor_scan() tries now to select the right
> op codes, timing parameters (number of mode and dummy cycles) and erase
> sector size by parsing the Serial Flash Discoverable Parameter (SFDP)
> tables, when available, as defined in the JEDEC JESD216 specifications.
> When SFDP tables are not available, legacy settings are still used for
> backward compatibility (SPI and earlier QSPI memories).
> Support of SPI memories >128Mbits is also improved by using the 4byte
> address instruction set, when available. Using those dedicated op codes
> is stateless as opposed to enter the 4byte address mode, hence a better
> compatibility with some boot loaders which expect to use 3byte address
> op codes.

The memories which are > 128Mbits should have 4-bytes addressing
support based on my experience, do you think BAR is also required
atleast from spi-nor side?

Jagan Teki
Free Software Engineer |
U-Boot, Linux | Upstream Maintainer
Hyderabad, India.