Commit 63cef81b authored by Dave Jiang's avatar Dave Jiang Committed by Dan Williams
Browse files

cxl: Add callback to parse the DSLBIS subtable from CDAT 



Provide a callback to parse the Device Scoped Latency and Bandwidth
Information Structure (DSLBIS) in the CDAT structures. The DSLBIS
contains the bandwidth and latency information that's tied to a DSMAS
handle. The driver will retrieve the read and write latency and
bandwidth associated with the DSMAS which is tied to a DPA range.

Coherent Device Attribute Table 1.03 2.1 Device Scoped Latency and
Bandwidth Information Structure (DSLBIS)

Reviewed-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: default avatarDave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/170319620005.2212653.7475488478229720542.stgit@djiang5-mobl3


Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent ad6f04c0

drivers/cxl/core/cdat.c

+100 −2
Original line number Diff line number Diff line
@@ -3,12 +3,15 @@ 
#include <linux/acpi.h>

#include <linux/xarray.h>

#include <linux/fw_table.h>

#include <linux/node.h>

#include <linux/overflow.h>

#include "cxlpci.h"

#include "cxl.h"



struct dsmas_entry {

	struct range dpa_range;

	u8 handle;

	struct access_coordinate coord;

};



static int cdat_dsmas_handler(union acpi_subtable_headers *header, void *arg,
@@ -49,11 +52,106 @@ static int cdat_dsmas_handler(union acpi_subtable_headers *header, void *arg, 
	return 0;

}



static void cxl_access_coordinate_set(struct access_coordinate *coord,

				      int access, unsigned int val)

{

	switch (access) {

	case ACPI_HMAT_ACCESS_LATENCY:

		coord->read_latency = val;

		coord->write_latency = val;

		break;

	case ACPI_HMAT_READ_LATENCY:

		coord->read_latency = val;

		break;

	case ACPI_HMAT_WRITE_LATENCY:

		coord->write_latency = val;

		break;

	case ACPI_HMAT_ACCESS_BANDWIDTH:

		coord->read_bandwidth = val;

		coord->write_bandwidth = val;

		break;

	case ACPI_HMAT_READ_BANDWIDTH:

		coord->read_bandwidth = val;

		break;

	case ACPI_HMAT_WRITE_BANDWIDTH:

		coord->write_bandwidth = val;

		break;

	}

}



static int cdat_dslbis_handler(union acpi_subtable_headers *header, void *arg,

			       const unsigned long end)

{

	struct acpi_cdat_header *hdr = &header->cdat;

	struct acpi_cdat_dslbis *dslbis;

	int size = sizeof(*hdr) + sizeof(*dslbis);

	struct xarray *dsmas_xa = arg;

	struct dsmas_entry *dent;

	__le64 le_base;

	__le16 le_val;

	u64 val;

	u16 len;

	int rc;



	len = le16_to_cpu((__force __le16)hdr->length);

	if (len != size || (unsigned long)hdr + len > end) {

		pr_warn("Malformed DSLBIS table length: (%u:%u)\n", size, len);

		return -EINVAL;

	}



	/* Skip common header */

	dslbis = (struct acpi_cdat_dslbis *)(hdr + 1);



	/* Skip unrecognized data type */

	if (dslbis->data_type > ACPI_HMAT_WRITE_BANDWIDTH)

		return 0;



	/* Not a memory type, skip */

	if ((dslbis->flags & ACPI_HMAT_MEMORY_HIERARCHY) != ACPI_HMAT_MEMORY)

		return 0;



	dent = xa_load(dsmas_xa, dslbis->handle);

	if (!dent) {

		pr_warn("No matching DSMAS entry for DSLBIS entry.\n");

		return 0;

	}



	le_base = (__force __le64)dslbis->entry_base_unit;

	le_val = (__force __le16)dslbis->entry[0];

	rc = check_mul_overflow(le64_to_cpu(le_base),

				le16_to_cpu(le_val), &val);

	if (rc)

		pr_warn("DSLBIS value overflowed.\n");



	cxl_access_coordinate_set(&dent->coord, dslbis->data_type, val);



	return 0;

}



static int cdat_table_parse_output(int rc)

{

	if (rc < 0)

		return rc;

	if (rc == 0)

		return -ENOENT;



	return 0;

}



static int cxl_cdat_endpoint_process(struct cxl_port *port,

				     struct xarray *dsmas_xa)

{

	return cdat_table_parse(ACPI_CDAT_TYPE_DSMAS, cdat_dsmas_handler,

	int rc;



	rc = cdat_table_parse(ACPI_CDAT_TYPE_DSMAS, cdat_dsmas_handler,

			      dsmas_xa, port->cdat.table);

	rc = cdat_table_parse_output(rc);

	if (rc)

		return rc;



	rc = cdat_table_parse(ACPI_CDAT_TYPE_DSLBIS, cdat_dslbis_handler,

			      dsmas_xa, port->cdat.table);

	return cdat_table_parse_output(rc);

}



static void discard_dsmas(struct xarray *xa)