[EXT] Re: Issues with SPI NOR flash

[Aaron Williams]

Hi Andrew,

I did, thank you.

The issue is that I had to unbind the driver when powering on our SOC and bind 
it again when we power our SOC off. That solved the problem and allows the SPI 
NOR to be reinitialized into the proper mode. Right now I have this in our 
power management process.

-Aaron

On Monday, February 11, 2019 2:57:18 PM PST Andrew Jeffery wrote:
> External Email
> 
> ----------------------------------------------------------------------
> Hi Aaron,
> 
> On Tue, 8 Jan 2019, at 21:52, Aaron Williams wrote:
> > Hi all,
> > 
> > I'm running into a problem with the SPI NOR connected to our host
> > processor. We're using a Macronix MX25L25645GMI-08G connected to the spi1
> > device on an AST2500. This device is muxed between our host processor and
> > the BMC. When our host processor is powered off, the BMC has exclusive
> > access to it.
> > 
> > Anyway, the behavior is that I can read the SPI NOR without any
> > difficulty,
> > however, when I write to it the SPI nor appears to be filled with garbage.
> > If I had to guess, I'd guess that the SPI driver is not waiting for the
> > SPI NOR to complete the write operation before moving to the next block.
> > 
> > Here is the relevant section from our device tree:
> > 
> > &spi1 {
> > 
> > 	status = "okay";
> > 	flash at 0 {
> > 	
> > 		status = "okay";
> > 		compatible = "jedec,spi-nor", "spi-nor";
> > 		label = "host";
> > 		m25p,fast-read;
> > 		spi-tx-bus-width = <1>;
> > 		spi-rx-bus-width = <1>;
> > 		spi-max-frequency = <50000000>;
> > 		partitions {
> > 		
> > 			compatible = "fixed-partitions";
> > 			#address-cells = <1>;
> > 			#size-cells = <1>;
> > 			
> > 			bootloader at 0 {
> > 			
> > 				reg = <0x0 0x1000000>;
> > 				label = "host-
> > 
> > bootloader";
> > 
> > 			};
> > 			kernel at 1000000 {
> > 			
> > 				reg = <0x1000000
> > 
> > 0x1000000>;
> > 
> > 				label = "host-kernel";
> > 			
> > 			};
> > 		
> > 		};
> > 	
> > 	};
> > 
> > };
> > 
> > Note that our host is also running 4.19 and has no trouble writing to the
> > SPI NOR. The corruption seems worse when flashcp is used compared to just
> > cp. I noticed that flashcp writes in 4K blocks. The Macronix device has a
> > 256 byte page buffer. I have tried slowing down the bus to 5MHz and that
> > made no difference. Note that we are currently using single bit mode for
> > both the host and BMC processors for this flash, though we plan to move
> > to move to QPI on the host processor later.
> > 
> > Before the write operation the host processor has not had any access to
> > the
> > SPI NOR. The host is powered down and the BMC is rebooted to force a clean
> > state.
> 
> Did you find the problem? I've added Cédric to Cc in case you haven't - he
> should be able to answer questions about the flash stack.
> 
> Andrew

-- 
Aaron Williams
Senior Software Engineer
Marvell Semiconductor, Inc.
(408) 943-7198	(510) 789-8988 (cell)