On Wednesday 24 August 2016 04:21 PM, Hannes Schmelzer wrote:
On 08/24/2016 12:35 PM, Vignesh R wrote:
Hi,
Hi Vignesh,
On Wednesday 24 August 2016 03:35 PM, Hannes Schmelzer wrote:
During probing flashes on the spi bus using the "sf probe" command, a maybe existing flash (from fdt) is unbound and removed to force the 'spi_flash_probe_bus_cs' really scanning the bus.
Today the bus is probed with speed 0, this triggers several fall-back mechanism (mostly in the low-level drivers) to catch the impossible zero speed. Result of this is, that the spi-flash runs at very low speed depending on the minimum given by low-level driver/hardware.
Values like 'spi-max-frequency' from devicetree are ignored totally today.
This commit changes as following:
- if there was already some flash binding in devicetree (having some spi-max-frequency within) speed is taken from it
- if no flash binding was present for speed the 'spi-max-frequency' from the responsible spi node is taken.
Signed-off-by: Hannes Schmelzer oe5hpm@oevsv.at
With commit 96907c0fe50a8 ("dm: spi: Read default speed and mode values from DT") sf probe picks spi-max-frequency from DT if not specified as argument.
But when sf probe is called second time, the command fails to pick up speed from DT. This is because flash node is unbound from the SPI controller children nodes. Below patch should fix this issue: https://patchwork.ozlabs.org/patch/659979/
sry ... i didn't took notice about this patch at the beginning of mine. Just reviewed and tested it.
The named patch makes things a bit better but not good. Speed for flash still has no relationship to 'spi-max-frequency' from the spi-bus nor with a maybe defined flash in dts.
Rather the #define CONFIG_ENV_SPI_MAX_HZ is used.
sf probe calls do_spi_flash_probe() -spi_flash_probe_bus_cs() -spi_get_bus_and_cs()
In spi_get_bus_and_cs(): if (!speed) { speed = plat->max_hz; mode = plat->mode; } This should set speed to spi-max-frequency as per flash DT node.
AFAIU, saveenv() uses CONFIG_ENV_SPI_MAX_HZ only when CONFIG_DM_SPI_FLASH is not defined. Could please explain how CONFIG_ENV_SPI_MAX_HZ takes precedence over spi-max-frequency during sf probe?