Re: [PATCH v2 1/3] cxl/region: Move HPA setup to cxl_region_attach()

[Jonathan Cameron <Jonathan.Cameron@huawei.com>]

On Fri, 05 Aug 2022 13:27:40 -0700
Dan Williams <dan.j.williams@intel.com> wrote:

> A recent bug fix added the setup of the endpoint decoder interleave
> geometry settings to cxl_region_attach(). Move the HPA setup there as
> well to keep all endpoint decoder parameter setting in a central
> location.
> 
> For symmetry, move endpoint HPA teardown to cxl_region_detach(), and for
> switches move HPA setup / teardown to cxl_port_{setup,reset}_targets().
> 
> Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
LGTM

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

I'm not yet hammering the detach path in my local testing, but
this looks unlikely to break anything.

Jonathan

> ---
>  drivers/cxl/core/hdm.c    |   26 ++------------------------
>  drivers/cxl/core/region.c |   24 ++++++++++++++++++++++--
>  2 files changed, 24 insertions(+), 26 deletions(-)
> 
> diff --git a/drivers/cxl/core/hdm.c b/drivers/cxl/core/hdm.c
> index 8143e2615957..e096f74e19df 100644
> --- a/drivers/cxl/core/hdm.c
> +++ b/drivers/cxl/core/hdm.c
> @@ -499,28 +499,6 @@ static void cxld_set_type(struct cxl_decoder *cxld, u32 *ctrl)
>  			  CXL_HDM_DECODER0_CTRL_TYPE);
>  }
>  
> -static void cxld_set_hpa(struct cxl_decoder *cxld, u64 *base, u64 *size)
> -{
> -	struct cxl_region *cxlr = cxld->region;
> -	struct cxl_region_params *p = &cxlr->params;
> -
> -	cxld->hpa_range = (struct range) {
> -		.start = p->res->start,
> -		.end = p->res->end,
> -	};
> -
> -	*base = p->res->start;
> -	*size = resource_size(p->res);
> -}
> -
> -static void cxld_clear_hpa(struct cxl_decoder *cxld)
> -{
> -	cxld->hpa_range = (struct range) {
> -		.start = 0,
> -		.end = -1,
> -	};
> -}
> -
>  static int cxlsd_set_targets(struct cxl_switch_decoder *cxlsd, u64 *tgt)
>  {
>  	struct cxl_dport **t = &cxlsd->target[0];
> @@ -601,7 +579,8 @@ static int cxl_decoder_commit(struct cxl_decoder *cxld)
>  	ctrl = readl(hdm + CXL_HDM_DECODER0_CTRL_OFFSET(cxld->id));
>  	cxld_set_interleave(cxld, &ctrl);
>  	cxld_set_type(cxld, &ctrl);
> -	cxld_set_hpa(cxld, &base, &size);
> +	base = cxld->hpa_range.start;
> +	size = range_len(&cxld->hpa_range);
>  
>  	writel(upper_32_bits(base), hdm + CXL_HDM_DECODER0_BASE_HIGH_OFFSET(id));
>  	writel(lower_32_bits(base), hdm + CXL_HDM_DECODER0_BASE_LOW_OFFSET(id));
> @@ -674,7 +653,6 @@ static int cxl_decoder_reset(struct cxl_decoder *cxld)
>  	ctrl &= ~CXL_HDM_DECODER0_CTRL_COMMIT;
>  	writel(ctrl, hdm + CXL_HDM_DECODER0_CTRL_OFFSET(id));
>  
> -	cxld_clear_hpa(cxld);
>  	writel(0, hdm + CXL_HDM_DECODER0_SIZE_HIGH_OFFSET(id));
>  	writel(0, hdm + CXL_HDM_DECODER0_SIZE_LOW_OFFSET(id));
>  	writel(0, hdm + CXL_HDM_DECODER0_BASE_HIGH_OFFSET(id));
> diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
> index 40f04c543e41..e71077beb021 100644
> --- a/drivers/cxl/core/region.c
> +++ b/drivers/cxl/core/region.c
> @@ -1044,6 +1044,10 @@ static int cxl_port_setup_targets(struct cxl_port *port,
>  
>  	cxld->interleave_ways = iw;
>  	cxld->interleave_granularity = ig;
> +	cxld->hpa_range = (struct range) {
> +		.start = p->res->start,
> +		.end = p->res->end,
> +	};
>  	dev_dbg(&cxlr->dev, "%s:%s iw: %d ig: %d\n", dev_name(port->uport),
>  		dev_name(&port->dev), iw, ig);
>  add_target:
> @@ -1070,13 +1074,21 @@ static void cxl_port_reset_targets(struct cxl_port *port,
>  				   struct cxl_region *cxlr)
>  {
>  	struct cxl_region_ref *cxl_rr = cxl_rr_load(port, cxlr);
> +	struct cxl_decoder *cxld;
>  
>  	/*
>  	 * After the last endpoint has been detached the entire cxl_rr may now
>  	 * be gone.
>  	 */
> -	if (cxl_rr)
> -		cxl_rr->nr_targets_set = 0;
> +	if (!cxl_rr)
> +		return;
> +	cxl_rr->nr_targets_set = 0;
> +
> +	cxld = cxl_rr->decoder;
> +	cxld->hpa_range = (struct range) {
> +		.start = 0,
> +		.end = -1,
> +	};
>  }
>  
>  static void cxl_region_teardown_targets(struct cxl_region *cxlr)
> @@ -1257,6 +1269,10 @@ static int cxl_region_attach(struct cxl_region *cxlr,
>  
>  	cxled->cxld.interleave_ways = p->interleave_ways;
>  	cxled->cxld.interleave_granularity = p->interleave_granularity;
> +	cxled->cxld.hpa_range = (struct range) {
> +		.start = p->res->start,
> +		.end = p->res->end,
> +	};
>  
>  	return 0;
>  
> @@ -1315,6 +1331,10 @@ static int cxl_region_detach(struct cxl_endpoint_decoder *cxled)
>  	}
>  	p->targets[cxled->pos] = NULL;
>  	p->nr_targets--;
> +	cxled->cxld.hpa_range = (struct range) {
> +		.start = 0,
> +		.end = -1,
> +	};
>  
>  	/* notify the region driver that one of its targets has departed */
>  	up_write(&cxl_region_rwsem);
>