[PATCH 01/11] spi: rk: Limit transfers to (64K - 1) bytes

[Kever Yang]

On 2019/12/21 下午3:54, Jagan Teki wrote:
> The Rockchip SPI controller's length register only supports 16-bits,
> yielding a maximum length of 64KiB (the CTRLR1 register holds "length -
> 1"). Trying to transfer more than that (e.g., with a large SPI flash
> read) will cause the driver to hang.
>
> Now, it seems that while theoretically we should be able to program
> CTRLR1 with 0xffff, and get a 64KiB transfer, but that also seems to
> cause the core to choke, so stick with a maximum of 64K - 1 bytes --
> i.e., 0xffff.
>
> Note, that the size is further divided into 'minus 1' while writing
> into CTRLR1.
>
> This change fixed two different read issues,
>
> 1. sf read failure when with > 0x10000
>
> 2. Boot from SPI flash failed during spi_flash_read call in
>     common/spl/spl_spi.c
>
> Observed and Tested in
> - Rockpro64 with Gigadevice flash
> - ROC-RK3399-PC with Winbond flash
>
> Signed-off-by: Jagan Teki <jagan at amarulasolutions.com>

Reviewed-by: Kever Yang <kever.yang at rock-chips.com>

Thanks,
- Kever
> ---
>   drivers/spi/rk_spi.c | 10 ++++++++--
>   1 file changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/spi/rk_spi.c b/drivers/spi/rk_spi.c
> index c04535ac44..95eeb8307a 100644
> --- a/drivers/spi/rk_spi.c
> +++ b/drivers/spi/rk_spi.c
> @@ -27,6 +27,12 @@
>   /* Change to 1 to output registers at the start of each transaction */
>   #define DEBUG_RK_SPI	0
>   
> +/*
> + * ctrlr1 is 16-bits, so we should support lengths of 0xffff + 1. However,
> + * the controller seems to hang when given 0x10000, so stick with this for now.
> + */
> +#define ROCKCHIP_SPI_MAX_TRANLEN		0xffff
> +
>   struct rockchip_spi_params {
>   	/* RXFIFO overruns and TXFIFO underruns stop the master clock */
>   	bool master_manages_fifo;
> @@ -367,7 +373,7 @@ static inline int rockchip_spi_16bit_reader(struct udevice *dev,
>   	 * represented in CTRLR1.
>   	 */
>   	if (data && data->master_manages_fifo)
> -		max_chunk_size = 0x10000;
> +		max_chunk_size = ROCKCHIP_SPI_MAX_TRANLEN;
>   
>   	// rockchip_spi_configure(dev, mode, size)
>   	rkspi_enable_chip(regs, false);
> @@ -451,7 +457,7 @@ static int rockchip_spi_xfer(struct udevice *dev, unsigned int bitlen,
>   
>   	/* This is the original 8bit reader/writer code */
>   	while (len > 0) {
> -		int todo = min(len, 0x10000);
> +		int todo = min(len, ROCKCHIP_SPI_MAX_TRANLEN);
>   
>   		rkspi_enable_chip(regs, false);
>   		writel(todo - 1, &regs->ctrlr1);