Dave Jiang wrote:
> The CDAT table is very similar to ACPI tables when it comes to sub-table
> and entry structures. The helper functions can be also used to parse the
> CDAT table. Add support to the helper functions to deal with an external
> CDAT table, and also handle the endieness since CDAT can be processed by a
> BE host. Export a function cdat_table_parse() for CXL driver to parse
> a CDAT table.
>
> In order to minimize ACPICA code changes, __force is being utilized to deal
> with the case of a big endien (BE) host parsing a CDAT. All CDAT data
> structure variables are being force casted to __leX as appropriate.
>
> Cc: Rafael J. Wysocki <rafael@xxxxxxxxxx>
> Cc: Len Brown <lenb@xxxxxxxxxx>
> Signed-off-by: Dave Jiang <dave.jiang@xxxxxxxxx>
>
> ---
> v2:
> - Make acpi_table_header and acpi_table_cdat a union. (Jonathan)
> - Use local var to make acpi_table_get_length() more readable. (Jonathan)
> - Remove ACPI_SIG_CDAT define, already defined.
> ---
> drivers/acpi/tables.c | 5 +++-
> drivers/acpi/tables_lib.c | 52 ++++++++++++++++++++++++++++++++++++++++++---
> include/linux/acpi.h | 22 +++++++++++++++++--
> 3 files changed, 72 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/acpi/tables.c b/drivers/acpi/tables.c
> index cfc76efd8788..f7e1ea192576 100644
> --- a/drivers/acpi/tables.c
> +++ b/drivers/acpi/tables.c
> @@ -241,8 +241,9 @@ int __init_or_acpilib acpi_table_parse_entries_array(
> return -ENODEV;
> }
>
> - count = acpi_parse_entries_array(id, table_size, table_header,
> - proc, proc_num, max_entries);
> + count = acpi_parse_entries_array(id, table_size,
> + (union table_header *)table_header,
I think the force cast can be cleaned up, more below...
> + proc, proc_num, max_entries);
>
> acpi_put_table(table_header);
> return count;
[..]
> diff --git a/include/linux/acpi.h b/include/linux/acpi.h
> index 57ffba91bfb5..4a5b40463048 100644
> --- a/include/linux/acpi.h
> +++ b/include/linux/acpi.h
> @@ -22,11 +22,17 @@
> #include <acpi/acpi.h>
>
> /* Table Handlers */
> +union table_header {
> + struct acpi_table_header acpi;
> + struct acpi_table_cdat cdat;
> +};
'table_header' seems too generic a name for a type in a header file
included as widely as acpi.h. How about 'union acpi_parse_header'?
Moreover I think the type-casting when calling the helpers might look
better with explicit type-punning showing the conversion from ACPI and
CDAT callers into the common parser. Something like the following folded
on top (only compile tested):
-- >8 --
diff --git a/drivers/acpi/tables.c b/drivers/acpi/tables.c
index f7e1ea192576..ef31232fdcfb 100644
--- a/drivers/acpi/tables.c
+++ b/drivers/acpi/tables.c
@@ -219,7 +219,7 @@ int __init_or_acpilib acpi_table_parse_entries_array(
char *id, unsigned long table_size, struct acpi_subtable_proc *proc,
int proc_num, unsigned int max_entries)
{
- struct acpi_table_header *table_header = NULL;
+ union acpi_convert_header hdr;
int count;
u32 instance = 0;
@@ -235,17 +235,16 @@ int __init_or_acpilib acpi_table_parse_entries_array(
if (!strncmp(id, ACPI_SIG_MADT, 4))
instance = acpi_apic_instance;
- acpi_get_table(id, instance, &table_header);
- if (!table_header) {
+ acpi_get_table(id, instance, &hdr.acpi);
+ if (!hdr.acpi) {
pr_debug("%4.4s not present\n", id);
return -ENODEV;
}
- count = acpi_parse_entries_array(id, table_size,
- (union table_header *)table_header,
- proc, proc_num, max_entries);
+ count = acpi_parse_entries_array(id, table_size, hdr.parse, proc,
+ proc_num, max_entries);
- acpi_put_table(table_header);
+ acpi_put_table(hdr.acpi);
return count;
}
diff --git a/drivers/acpi/tables_lib.c b/drivers/acpi/tables_lib.c
index 71e2fb1735e5..bd886900762a 100644
--- a/drivers/acpi/tables_lib.c
+++ b/drivers/acpi/tables_lib.c
@@ -105,7 +105,7 @@ static enum acpi_subtable_type acpi_get_subtable_type(char *id)
}
static unsigned long acpi_table_get_length(enum acpi_subtable_type type,
- union table_header *hdr)
+ union acpi_parse_header *hdr)
{
if (type == CDAT_SUBTABLE) {
__le32 length = (__force __le32)hdr->cdat.length;
@@ -155,7 +155,7 @@ static int call_handler(struct acpi_subtable_proc *proc,
* Otherwise, -ENODEV or -EINVAL is returned.
*/
int acpi_parse_entries_array(char *id, unsigned long table_size,
- union table_header *table_header,
+ union acpi_parse_header *table_header,
struct acpi_subtable_proc *proc,
int proc_num, unsigned int max_entries)
{
@@ -224,6 +224,7 @@ int cdat_table_parse(enum acpi_cdat_type type,
acpi_tbl_entry_handler_arg handler_arg, void *arg,
struct acpi_table_cdat *table_header)
{
+ union acpi_convert_header hdr = { .cdat = table_header };
struct acpi_subtable_proc proc = {
.id = type,
.handler_arg = handler_arg,
@@ -234,7 +235,7 @@ int cdat_table_parse(enum acpi_cdat_type type,
return -EINVAL;
return acpi_parse_entries_array(ACPI_SIG_CDAT,
- sizeof(struct acpi_table_cdat),
- (union table_header *)table_header, &proc, 1, 0);
+ sizeof(struct acpi_table_cdat),
+ hdr.parse, &proc, 1, 0);
}
EXPORT_SYMBOL_NS_GPL(cdat_table_parse, CXL);
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index dcaaaffff318..40caea4ba227 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -25,11 +25,21 @@ struct irq_domain_ops;
#include <acpi/acpi.h>
/* Table Handlers */
-union table_header {
+union acpi_parse_header {
struct acpi_table_header acpi;
struct acpi_table_cdat cdat;
};
+/*
+ * Perform type punning between ACPI and CDAT callers of the core table
+ * parsing routines that use acpi_parse_header internally
+ */
+union acpi_convert_header {
+ struct acpi_table_header *acpi;
+ struct acpi_table_cdat *cdat;
+ union acpi_parse_header *parse;
+};
+
union acpi_subtable_headers {
struct acpi_subtable_header common;
struct acpi_hmat_structure hmat;
@@ -1539,7 +1549,7 @@ static inline void acpi_device_notify_remove(struct device *dev) { }
#ifdef CONFIG_ACPI_TABLES_LIB
int acpi_parse_entries_array(char *id, unsigned long table_size,
- union table_header *table_header,
+ union acpi_parse_header *table_header,
struct acpi_subtable_proc *proc,
int proc_num, unsigned int max_entries);
@@ -1547,10 +1557,11 @@ int cdat_table_parse(enum acpi_cdat_type type,
acpi_tbl_entry_handler_arg handler, void *arg,
struct acpi_table_cdat *table_header);
#else
-static inline int acpi_parse_entries_array(
- char *id, unsigned long table_size,
- union table_header *table_header, struct acpi_subtable_proc *proc,
- int proc_num, unsigned int max_entries)
+static inline int
+acpi_parse_entries_array(char *id, unsigned long table_size,
+ union acpi_parse_header *table_header,
+ struct acpi_subtable_proc *proc, int proc_num,
+ unsigned int max_entries)
{
return -EOPNOTSUPP;
}
