Re: [PATCH v2 2/3] mtd: spi-nor: Altera ASMI Parallel II IP Core

[matthew . gerlach]

On Tue, 10 Oct 2017, Marek Vasut wrote:

> On 09/20/2017 08:28 PM, matthew.gerlach@xxxxxxxxxxxxxxx wrote:
> > From: Matthew Gerlach <matthew.gerlach@xxxxxxxxxxxxxxx>
> >
> > This patch adds support for a spi-nor, platform driver for the
> > Altera ASMI Parallel II IP Core.  The intended use case is to be able
> > to update the flash used to load a FPGA at power up with mtd-utils.
> >
> > Signed-off-by: Matthew Gerlach <matthew.gerlach@xxxxxxxxxxxxxxx>
> > ---
> > v2:
> >     minor checkpatch fixing by Wu Hao <hao.wu@xxxxxxxxx>
> >     Use read_dummy value as suggested by Cyrille Pitchen.
> >     Don't assume 4 byte addressing (Cryille Pichecn and Marek Vasut).
> >     Fixed #define indenting as suggested by Marek Vasut.
> >     Added units to timer values as suggested by Marek Vasut.
> >     Use io(read|write)8_rep() as suggested by Marek Vasut.
> >     Renamed function prefixed with __ as suggested by Marek Vasut.
>
> [...]
>
> > +#define QSPI_ACTION_REG			0
> > +#define QSPI_ACTION_RST			BIT(0)
> > +#define QSPI_ACTION_EN			BIT(1)
> > +#define QSPI_ACTION_SC			BIT(2)
> > +#define QSPI_ACTION_CHIP_SEL_SFT	4
> > +#define QSPI_ACTION_DUMMY_SFT		8
> > +#define QSPI_ACTION_READ_BACK_SFT	16
> > +
> > +#define QSPI_FIFO_CNT_REG		4
> > +#define QSPI_FIFO_DEPTH			0x200
> > +#define QSPI_FIFO_CNT_MSK		0x3ff
> > +#define QSPI_FIFO_CNT_RX_SFT		0
> > +#define QSPI_FIFO_CNT_TX_SFT		12
> > +
> > +#define QSPI_DATA_REG			0x8
> > +
> > +#define QSPI_POLL_TIMEOUT_US		10000000
>
> 10 s poll timeout ? :)

Hi Marek,

The 10s timeout is fairly arbitrary.  In other words, I pulled it out of 
thin air.  Can you suggest a better timeout?  From a practical standpoint 10s 
seemed to be much better than no timeout when I was debugging bad FPGA 
images.  Without a timeout I was hanging the system when the FPGA image 
failed.  With this timeout, we get a nice message and Linux keeps running 
happily.

Thanks for the feedback,

Matthew Gerlach

> > +#define QSPI_POLL_INTERVAL_US		 5 >> + >> +struct 
altera_asmip2 { >
> [...]
>
> Otherwise looks good
>
> --
> Best regards,
> Marek Vasut