On Thu, 14 Jul 2022 17:01:28 -0700
Dan Williams <dan.j.williams@xxxxxxxxx> wrote:
> The CXL specification enforces that endpoint decoders are committed in
> hw instance id order. In preparation for adding dynamic DPA allocation,
> record the hw instance id in endpoint decoders, and enforce allocations
> to occur in hw instance id order.
>
> Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Lifting from v1 thread to ease picking it up.
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
> ---
> drivers/cxl/core/hdm.c | 15 +++++++++++++++
> drivers/cxl/core/port.c | 1 +
> drivers/cxl/cxl.h | 2 ++
> 3 files changed, 18 insertions(+)
>
> diff --git a/drivers/cxl/core/hdm.c b/drivers/cxl/core/hdm.c
> index acd46b0d69c6..582f48141767 100644
> --- a/drivers/cxl/core/hdm.c
> +++ b/drivers/cxl/core/hdm.c
> @@ -160,6 +160,7 @@ EXPORT_SYMBOL_NS_GPL(cxl_dpa_debug, CXL);
> static void __cxl_dpa_release(struct cxl_endpoint_decoder *cxled)
> {
> struct cxl_memdev *cxlmd = cxled_to_memdev(cxled);
> + struct cxl_port *port = cxled_to_port(cxled);
> struct cxl_dev_state *cxlds = cxlmd->cxlds;
> struct resource *res = cxled->dpa_res;
>
> @@ -171,6 +172,7 @@ static void __cxl_dpa_release(struct cxl_endpoint_decoder *cxled)
> cxled->skip = 0;
> __release_region(&cxlds->dpa_res, res->start, resource_size(res));
> cxled->dpa_res = NULL;
> + port->hdm_end--;
> }
>
> static void cxl_dpa_release(void *cxled)
> @@ -201,6 +203,18 @@ static int __cxl_dpa_reserve(struct cxl_endpoint_decoder *cxled,
> return -EBUSY;
> }
>
> + if (port->hdm_end + 1 != cxled->cxld.id) {
> + /*
> + * Assumes alloc and commit order is always in hardware instance
> + * order per expectations from 8.2.5.12.20 Committing Decoder
> + * Programming that enforce decoder[m] committed before
> + * decoder[m+1] commit start.
> + */
> + dev_dbg(dev, "decoder%d.%d: expected decoder%d.%d\n", port->id,
> + cxled->cxld.id, port->id, port->hdm_end + 1);
> + return -EBUSY;
> + }
> +
> if (skipped) {
> res = __request_region(&cxlds->dpa_res, base - skipped, skipped,
> dev_name(&cxled->cxld.dev), 0);
> @@ -233,6 +247,7 @@ static int __cxl_dpa_reserve(struct cxl_endpoint_decoder *cxled,
> cxled->cxld.id, cxled->dpa_res);
> cxled->mode = CXL_DECODER_MIXED;
> }
> + port->hdm_end++;
>
> return 0;
> }
> diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c
> index 0ac5dcd612e0..109611318760 100644
> --- a/drivers/cxl/core/port.c
> +++ b/drivers/cxl/core/port.c
> @@ -502,6 +502,7 @@ static struct cxl_port *cxl_port_alloc(struct device *uport,
>
> port->component_reg_phys = component_reg_phys;
> ida_init(&port->decoder_ida);
> + port->hdm_end = -1;
> INIT_LIST_HEAD(&port->dports);
> INIT_LIST_HEAD(&port->endpoints);
>
> diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
> index 3e7363dde80f..70cd24e4f3ce 100644
> --- a/drivers/cxl/cxl.h
> +++ b/drivers/cxl/cxl.h
> @@ -333,6 +333,7 @@ struct cxl_nvdimm {
> * @dports: cxl_dport instances referenced by decoders
> * @endpoints: cxl_ep instances, endpoints that are a descendant of this port
> * @decoder_ida: allocator for decoder ids
> + * @hdm_end: track last allocated HDM decoder instance for allocation ordering
> * @component_reg_phys: component register capability base address (optional)
> * @dead: last ep has been removed, force port re-creation
> * @depth: How deep this port is relative to the root. depth 0 is the root.
> @@ -345,6 +346,7 @@ struct cxl_port {
> struct list_head dports;
> struct list_head endpoints;
> struct ida decoder_ida;
> + int hdm_end;
> resource_size_t component_reg_phys;
> bool dead;
> unsigned int depth;
>
