> ---------- Forwarded message ---------- > From: Linus Walleij <linus.walleij@xxxxxxxxxx> > Date: Tue, Feb 22, 2011 at 2:19 AM > Subject: Re: [RFC] MMC: error handling improvements > To: Brian Swetland <swetland@xxxxxxxxxx>, David Brown > <davidb@xxxxxxxxxxxxxx >> > Cc: Russell King - ARM Linux <linux@xxxxxxxxxxxxxxxx>, Chris Ball < > cjb@xxxxxxxxxx>, linux-mmc@xxxxxxxxxxxxxxx, > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > > > Out of sheer curiosity, Qualcomm/CodeAurora guys: > > if you dump out the registers at offset 0xfe0-0xfff on the > SDCC, does it contain a valid PrimeCell ID? Anyone who > can make a hexdump of it? > > It is possible to hardcode an AMBA ID to use this driver > even if this area is just 0x0000... but I'm just curious > about how different silicon vendors treat these registers, > e.g. if they contain something sensible. > Linus, These Prime cell ID registers are removed in the newer versions of the MSM SDCC controller and are replaced with a different register that indicates the controller version number. So, using these prime cell ID registers may not be an option for us. Nevertheless, as you pointed out we can hard code the AMBA ID in the platform device data and use that in the mmci driver to handle stuff specific to this controller similar to what is done for ST variant in mmci driver. Though the bulk of the MSM SDCC controller is designed around PL180, there are still some modifications to include flow control, SDIO support, Data Mover interface (DMA engine on Qualcomm MSMs) etc. Support/ability to talk to the Data Mover is one of the main differences when compared to original PL180 prime cell. Our main concern in moving to mmci is support for DMA that needs to be added to this driver. I believe PL180 controller does have the ability to talk to DMA engines, but i dont see any relevant support for that in mmci driver, unless i grossly missed something. Regards P Murali Krishna Sent by a consultant of the Qualcomm Innovation Center, Inc. The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum. -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
