[coreboot] How to find out "page size" of a flash chip?

Peter Stuge peter at stuge.se
Wed Nov 19 07:50:48 CET 2008

Hello Yu Ning,

FENG Yu Ning wrote:
> Questions:
> 1. How do we decide the page-sizes of other SST(and other vendors)
> flash chips, which have no page mechanism?

The page_size member is considered an eraseblock size by the code.

> 2. Since we operate the flash chips (in case of ich) with
> ich_spi_read/write, which in turn call ich_spi_read/write_page,
> what happens to those chips without a page-read/write operation? I
> am going to investigate the source code and data sheets further,
> but it is appreciated if anyone familiar with this tell me directly
> (and it would guide me through the investigation).

As you may have found, the code is pretty ugly overall. In the case
of ichspi, read_page and write_page simply assume that it is possible
to read or write all of page_size bytes in a loop.

Other SPI "bus" drivers work differently, but page_size is always
assumed to describe an eraseblock size.


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