Re: [PATCH 04/23] dmaengine: sdxi: Feature discovery and initial configuration

[Frank Li <Frank.li@nxp.com>]

On Fri, Apr 10, 2026 at 08:07:14AM -0500, Nathan Lynch wrote:
> After bus-specific initialization, force the SDXI function to stopped
> state. This is the expected state from reset, but kexec or driver bugs
> can leave a function in other states from which the initialization
> code must be able to recover.

Move this paragraph to last because this major funciton is
"Discover via the capability register ..."

> +
....
> +/* Get the device to the GSV_STOP state. */
> +static int sdxi_dev_stop(struct sdxi_dev *sdxi)
> +{
> +	unsigned long deadline = jiffies + msecs_to_jiffies(1000);
> +	bool reset_issued = false;
> +
> +	do {
> +		enum sdxi_fn_gsv status = sdxi_dev_gsv(sdxi);
> +
> +		sdxi_dbg(sdxi, "%s: function state: %s\n", __func__, gsv_str(status));
> +
> +		switch (status) {
> +		case SDXI_GSV_ACTIVE:
> +			sdxi_write_fn_gsr(sdxi, SDXI_GSRV_STOP_SF);
> +			break;
> +		case SDXI_GSV_ERROR:
> +			if (!reset_issued) {
> +				sdxi_info(sdxi,
> +					  "function in error state, issuing reset\n");
> +				sdxi_write_fn_gsr(sdxi, SDXI_GSRV_RESET);
> +				reset_issued = true;
> +			} else {
> +				fsleep(1000);
> +			}
> +			break;
> +		case SDXI_GSV_STOP:
> +			return 0;
> +		case SDXI_GSV_INIT:
> +		case SDXI_GSV_STOPG_SF:
> +		case SDXI_GSV_STOPG_HD:
> +			/* transitional states, wait */
> +			sdxi_dbg(sdxi, "waiting for stop (gsv = %u)\n",
> +				 status);
> +			fsleep(1000);
> +			break;
> +		default:
> +			sdxi_err(sdxi, "unknown gsv %u, giving up\n", status);
> +			return -EIO;
> +		}
> +	} while (time_before(jiffies, deadline));

does read_poll_timeout() work?

>
> +#define sdxi_dbg(s, fmt, ...) dev_dbg(sdxi_to_dev(s), fmt, ## __VA_ARGS__)
> +#define sdxi_info(s, fmt, ...) dev_info(sdxi_to_dev(s), fmt, ## __VA_ARGS__)
> +#define sdxi_err(s, fmt, ...) dev_err(sdxi_to_dev(s), fmt, ## __VA_ARGS__)

suggest direct use dev_*

Frank