On 10/11/2017 07:00 PM, matthew.gerlach@xxxxxxxxxxxxxxx wrote: > > > 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. AFAIK the SPI subsystem has a timeout which is adaptive to the bus clock, maybe that's what you want to use here ? -- Best regards, Marek Vasut -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html