Add helper functions to parse the CDAT table and provide a callback to
parse the sub-table. Helpers are provided for DSMAS and DSLBIS sub-table
parsing. The code is patterned after the ACPI table parsing helpers.
Signed-off-by: Dave Jiang <dave.jiang@xxxxxxxxx>
---
drivers/cxl/core/Makefile | 1
drivers/cxl/core/cdat.c | 98 +++++++++++++++++++++++++++++++++++++++++++++
drivers/cxl/core/cdat.h | 15 +++++++
drivers/cxl/cxl.h | 9 ++++
4 files changed, 123 insertions(+)
create mode 100644 drivers/cxl/core/cdat.c
create mode 100644 drivers/cxl/core/cdat.h
diff --git a/drivers/cxl/core/Makefile b/drivers/cxl/core/Makefile
index 79c7257f4107..438ce27faf77 100644
--- a/drivers/cxl/core/Makefile
+++ b/drivers/cxl/core/Makefile
@@ -10,4 +10,5 @@ cxl_core-y += memdev.o
cxl_core-y += mbox.o
cxl_core-y += pci.o
cxl_core-y += hdm.o
+cxl_core-y += cdat.o
cxl_core-$(CONFIG_CXL_REGION) += region.o
diff --git a/drivers/cxl/core/cdat.c b/drivers/cxl/core/cdat.c
new file mode 100644
index 000000000000..be09c8a690f5
--- /dev/null
+++ b/drivers/cxl/core/cdat.c
@@ -0,0 +1,98 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright(c) 2023 Intel Corporation. All rights reserved. */
+#include "cxl.h"
+#include "cdat.h"
+
+static u8 cdat_get_subtable_entry_type(struct cdat_subtable_entry *entry)
+{
+ return entry->hdr->type;
+}
+
+static u16 cdat_get_subtable_entry_length(struct cdat_subtable_entry *entry)
+{
+ return entry->hdr->length;
+}
+
+static bool has_handler(struct cdat_subtable_proc *proc)
+{
+ return proc->handler;
+}
+
+static int call_handler(struct cdat_subtable_proc *proc,
+ struct cdat_subtable_entry *ent)
+{
+ if (proc->handler)
+ return proc->handler(ent->hdr, proc->arg);
+ return -EINVAL;
+}
+
+static int cdat_table_parse_entries(enum acpi_cdat_type type,
+ struct acpi_table_cdat *table_header,
+ struct cdat_subtable_proc *proc,
+ unsigned int max_entries)
+{
+ struct cdat_subtable_entry entry;
+ unsigned long table_end, entry_len;
+ int count = 0;
+ int rc;
+
+ if (!has_handler(proc))
+ return -EINVAL;
+
+ table_end = (unsigned long)table_header + table_header->length;
+
+ if (type >= ACPI_CDAT_TYPE_RESERVED)
+ return -EINVAL;
+
+ entry.type = type;
+ entry.hdr = (struct acpi_cdat_header *)((unsigned long)table_header +
+ sizeof(*table_header));
+
+ while ((unsigned long)entry.hdr < table_end) {
+ entry_len = cdat_get_subtable_entry_length(&entry);
+
+ if ((unsigned long)entry.hdr + entry_len > table_end)
+ return -EINVAL;
+
+ if (max_entries && count >= max_entries)
+ break;
+
+ if (entry_len == 0)
+ return -EINVAL;
+
+ if (cdat_get_subtable_entry_type(&entry) == type) {
+ rc = call_handler(proc, &entry);
+ if (rc)
+ return rc;
+ }
+
+ entry.hdr = (struct acpi_cdat_header *)((unsigned long)entry.hdr + entry_len);
+ count++;
+ }
+
+ return count;
+}
+
+int cdat_table_parse_dsmas(void *table, cdat_tbl_entry_handler handler, void *arg)
+{
+ struct acpi_table_cdat *header = (struct acpi_table_cdat *)table;
+ struct cdat_subtable_proc proc = {
+ .handler = handler,
+ .arg = arg,
+ };
+
+ return cdat_table_parse_entries(ACPI_CDAT_TYPE_DSMAS, header, &proc, 0);
+}
+EXPORT_SYMBOL_NS_GPL(cdat_table_parse_dsmas, CXL);
+
+int cdat_table_parse_dslbis(void *table, cdat_tbl_entry_handler handler, void *arg)
+{
+ struct acpi_table_cdat *header = (struct acpi_table_cdat *)table;
+ struct cdat_subtable_proc proc = {
+ .handler = handler,
+ .arg = arg,
+ };
+
+ return cdat_table_parse_entries(ACPI_CDAT_TYPE_DSLBIS, header, &proc, 0);
+}
+EXPORT_SYMBOL_NS_GPL(cdat_table_parse_dslbis, CXL);
diff --git a/drivers/cxl/core/cdat.h b/drivers/cxl/core/cdat.h
new file mode 100644
index 000000000000..f690325e82a6
--- /dev/null
+++ b/drivers/cxl/core/cdat.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/* Copyright(c) 2023 Intel Corporation. */
+#ifndef __CXL_CDAT_H__
+#define __CXL_CDAT_H__
+
+struct cdat_subtable_proc {
+ cdat_tbl_entry_handler handler;
+ void *arg;
+};
+
+struct cdat_subtable_entry {
+ struct acpi_cdat_header *hdr;
+ enum acpi_cdat_type type;
+};
+#endif
diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
index f558bbfc0332..839a121c1997 100644
--- a/drivers/cxl/cxl.h
+++ b/drivers/cxl/cxl.h
@@ -9,6 +9,7 @@
#include <linux/bitops.h>
#include <linux/log2.h>
#include <linux/io.h>
+#include <linux/acpi.h>
/**
* DOC: cxl objects
@@ -697,6 +698,14 @@ static inline struct cxl_pmem_region *to_cxl_pmem_region(struct device *dev)
}
#endif
+typedef int (*cdat_tbl_entry_handler)(struct acpi_cdat_header *header, void *arg);
+
+u8 cdat_table_checksum(u8 *buffer, u32 length);
+int cdat_table_parse_dsmas(void *table, cdat_tbl_entry_handler handler,
+ void *arg);
+int cdat_table_parse_dslbis(void *table, cdat_tbl_entry_handler handler,
+ void *arg);
+
/*
* Unit test builds overrides this to __weak, find the 'strong' version
* of these symbols in tools/testing/cxl/.
