[U-Boot] [PATCH v2 17/22] omap4: automatic sdram detection

Wolfgang Denk
2011-05-15T20:06:45Z

Dear Aneesh V,

In message <1305472900-4004-18-git-send-email-aneesh@ti.com> you wrote:
> Identify SDRAM devices connected to EMIF automatically:
> LPDDR2 devices have some Mode Registers that provide details
> about the device such as the type, density, bus width
> etc. EMIF has the capability to read these registers. If there
> are not devices connected to a given chip-select reading mode
> registers will return junk values. After reading as many such
> registers as possible and matching with expected ranges of
> values the driver can identify if there is a device connected
> to the respective CS. If we identify that a device is connected
> the values read give us complete details about the device.
>
> This along with the base AC timings specified by JESD209-2
> allows us to do a complete automatic initialization of
> SDRAM that works on all boards.
>
> Please note that the default AC timings specified by JESD209-2
> will be safe for all devices but not necessarily optimal. However,
> for the Elpida devices used on Panda and SDP the default timings
> are both safe and optimal.
>
> Signed-off-by: Aneesh V <aneesh@ti.com>
> ---
> arch/arm/cpu/armv7/omap4/emif.c | 177 +++++++++++++++++++++++++++++-
> arch/arm/cpu/armv7/omap4/sdram_elpida.c | 9 +-
> include/configs/omap4_sdp4430.h | 1 +
> 3 files changed, 176 insertions(+), 11 deletions(-)

How much of this is OMAP4 specific, and how much can be reused onother
SoCs as well?

Best regards,

Wolfgang Denk

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