On 3/18/21 2:26 PM, Pierre Morel wrote:
> Some tests require to disable a subchannel.
> Let's implement the css_disable() function.
>
> Signed-off-by: Pierre Morel <pmorel@xxxxxxxxxxxxx>
Looks ok, minor nits below.
> ---
> lib/s390x/css.h | 1 +
> lib/s390x/css_lib.c | 69 +++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 70 insertions(+)
>
> diff --git a/lib/s390x/css.h b/lib/s390x/css.h
> index 7e3d261..b0de3a3 100644
> --- a/lib/s390x/css.h
> +++ b/lib/s390x/css.h
> @@ -284,6 +284,7 @@ int css_enumerate(void);
> #define IO_SCH_ISC 3
> int css_enable(int schid, int isc);
> bool css_enabled(int schid);
> +int css_disable(int schid);
>
> /* Library functions */
> int start_ccw1_chain(unsigned int sid, struct ccw1 *ccw);
> diff --git a/lib/s390x/css_lib.c b/lib/s390x/css_lib.c
> index efc7057..f8db205 100644
> --- a/lib/s390x/css_lib.c
> +++ b/lib/s390x/css_lib.c
> @@ -186,6 +186,75 @@ bool css_enabled(int schid)
> }
> return true;
> }
> +
> +/*
> + * css_disable: disable the subchannel
> + * @schid: Subchannel Identifier
> + * Return value:
> + * On success: 0
> + * On error the CC of the faulty instruction
> + * or -1 if the retry count is exceeded.
> + */
> +int css_disable(int schid)
> +{
> + struct pmcw *pmcw = &schib.pmcw;
> + int retry_count = 0;
> + int cc;
> +
> + /* Read the SCHIB for this subchannel */
> + cc = stsch(schid, &schib);
> + if (cc) {
> + report_info("stsch: sch %08x failed with cc=%d", schid, cc);
> + return cc;
> + }
> +
> + if (!(pmcw->flags & PMCW_ENABLE)) {
> + report_info("stsch: sch %08x already disabled", schid);
> + return 0;
> + }
> +
> +retry:
> + /* Update the SCHIB to disable the subchannel */
> + pmcw->flags &= ~PMCW_ENABLE;
> +
> + /* Tell the CSS we want to modify the subchannel */
> + cc = msch(schid, &schib);
> + if (cc) {
> + /*
> + * If the subchannel is status pending or
> + * if a function is in progress,
> + * we consider both cases as errors.
> + */
Weird indentation, the lines should be longer, no?
> + report_info("msch: sch %08x failed with cc=%d", schid, cc);
> + return cc;
> + }
> +
> + /*
> + * Read the SCHIB again to verify the enablement
> + */
Can be one line
> + cc = stsch(schid, &schib);
> + if (cc) {
> + report_info("stsch: updating sch %08x failed with cc=%d",
> + schid, cc);
> + return cc;
> + }
> +
> + if (!(pmcw->flags & PMCW_ENABLE)) {
> + if (retry_count)
> + report_info("stsch: sch %08x successfully disabled after %d retries",
> + schid, retry_count);
> + return 0;
> + }
> +
> + if (retry_count++ < MAX_ENABLE_RETRIES) {
> + mdelay(10); /* the hardware was not ready, give it some time */
Personally I dislike comments at the end of lines except for
constant/variable comments. Just put it before the delay.
> + goto retry;
> + }
> +
> + report_info("msch: modifying sch %08x failed after %d retries. pmcw flags: %04x",
> + schid, retry_count, pmcw->flags);
> + return -1;
> +}
> /*
> * css_enable: enable the subchannel with the specified ISC
> * @schid: Subchannel Identifier
>
