On 2/15/22 11:16 AM, Niklas Cassel wrote:
From: Sean Anderson seanga2@gmail.com
The designware spi driver unconditionally uses polling.
The comment to spi_hw_init() also states that the function should disable interrupts.
According to the DesignWare DW_apb_ssi Databook, value 0xff in IMR enables all interrupts. Since we want to mask all interrupts write 0x0 instead.
On the canaan k210 board, pressing the reset button twice to reset the board will run u-boot. If u-boot boots Linux without having SPI interrupts masked, Linux will hang as soon as interrupts are enabled, because of an interrupt storm.
Properly masking the SPI interrupts in u-boot allows us to successfully boot Linux, even after resetting the board.
Fixes: 5bef6fd79f94 ("spi: Add designware master SPI DM driver used on SoCFPGA") Signed-off-by: Sean Anderson seanga2@gmail.com [Niklas: rewrite commit message] Signed-off-by: Niklas Cassel niklas.cassel@wdc.com
drivers/spi/designware_spi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/spi/designware_spi.c b/drivers/spi/designware_spi.c index f9b19a5ea4..47bea0b376 100644 --- a/drivers/spi/designware_spi.c +++ b/drivers/spi/designware_spi.c @@ -266,7 +266,7 @@ static int dw_spi_of_to_plat(struct udevice *bus) static void spi_hw_init(struct udevice *bus, struct dw_spi_priv *priv) { dw_write(priv, DW_SPI_SSIENR, 0);
- dw_write(priv, DW_SPI_IMR, 0xff);
dw_write(priv, DW_SPI_IMR, 0); dw_write(priv, DW_SPI_SSIENR, 1);
/*
Reviewed-by: Sean Anderson seanga2@gmail.com