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From: Albin Tonnerre <albin.tonnerre@free-electrons.com>
To: u-boot@lists.denx.de
Subject: [U-Boot] Environment and SPI drivers
Date: Mon, 15 Mar 2010 20:29:14 +0100	[thread overview]
Message-ID: <20100315192914.GA14032@pc-ran3241> (raw)

Hello,

The SPI framework provided by u-boot (spi_setup_slave, spi_xfer and the like)
cannot currently be used to read the environment from SPI devices. The reason is
that all the drivers implement spi_setup_slave using malloc(), and malloc()
cannot be used when env_init is called - this happens before mem_alloc_init.

I'm wondering what would be a proper fix for this. I don't think it is OK to say
'drivers reading the environment should not use the SPI framework', as those
drivers might be used to do others things - that would make the SPI framework
unsuitable for (e.g.) any SPI EEPROM. The only sane alternative I can see is
that we introduce spi_setup_slave_$whatever, which would work the same way as
spi_setup_slave, with the difference that it should be given caller-allocated
storage, so that we avoid the use for malloc().

Thoughts ?

Regards,
-- 
Albin Tonnerre, Free Electrons
Kernel, drivers and embedded Linux development,
consulting, training and support.
http://free-electrons.com

             reply	other threads:[~2010-03-15 19:29 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-03-15 19:29 Albin Tonnerre [this message]
2010-03-15 20:25 ` [U-Boot] Environment and SPI drivers Wolfgang Denk
2010-03-15 20:45   ` Albin Tonnerre

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