On Wed, 19 Apr 2023 13:21:25 -0700
Dave Jiang <dave.jiang@xxxxxxxxx> wrote:
> 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>
>
A few minor things inline. More than possible you addressed them
in earlier versions though.
Jonathan
> ---
> v2:
> - Use local headers to handle LE instead of ACPI header
> - Reduce complexity of parser function. (Jonathan)
> - Directly access header type. (Jonathan)
> - Simplify header ptr math. (Jonathan)
> - Move parsed counter to the correct location. (Jonathan)
> - Add LE to host conversion for entry length
> ---
> drivers/cxl/core/Makefile | 1
> drivers/cxl/core/cdat.c | 100 +++++++++++++++++++++++++++++++++++++++++++++
> drivers/cxl/cxlpci.h | 29 +++++++++++++
> 3 files changed, 130 insertions(+)
> create mode 100644 drivers/cxl/core/cdat.c
>
> diff --git a/drivers/cxl/core/Makefile b/drivers/cxl/core/Makefile
> index ca4ae31d8f57..867a8014b462 100644
> --- a/drivers/cxl/core/Makefile
> +++ b/drivers/cxl/core/Makefile
> @@ -12,5 +12,6 @@ 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-$(CONFIG_TRACING) += trace.o
> cxl_core-$(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..210f4499bddb
> --- /dev/null
> +++ b/drivers/cxl/core/cdat.c
> @@ -0,0 +1,100 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/* Copyright(c) 2023 Intel Corporation. All rights reserved. */
> +#include "cxlpci.h"
> +#include "cxl.h"
> +
> +static bool has_handler(struct cdat_subtable_proc *proc)
Even though they are static, I'd add a cxl_ or cdat_ prefix
to these to make it clear they are local.
> +{
> + return proc->handler;
> +}
> +
> +static int call_handler(struct cdat_subtable_proc *proc,
> + struct cdat_subtable_entry *ent)
> +{
> + if (has_handler(proc))
Do we need to check this again? It's checked in the parse_entries code
well before this point.
Also, if moving to checking it once, then is it worth the
little wrapper functions?
> + return proc->handler(ent->hdr, proc->arg);
> + return -EINVAL;
> +}
> +
> +static bool cdat_is_subtable_match(struct cdat_subtable_entry *ent)
> +{
> + return ent->hdr->type == ent->type;
> +}
> +
> +static int cdat_table_parse_entries(enum cdat_type type,
> + struct cdat_header *table_header,
> + struct cdat_subtable_proc *proc)
> +{
> + unsigned long table_end, entry_len;
> + struct cdat_subtable_entry entry;
> + int count = 0;
> + int rc;
> +
> + if (!has_handler(proc))
> + return -EINVAL;
> +
> + table_end = (unsigned long)table_header + table_header->length;
> +
> + if (type >= CDAT_TYPE_RESERVED)
> + return -EINVAL;
> +
> + entry.type = type;
> + entry.hdr = (struct cdat_entry_header *)(table_header + 1);
> +
> + while ((unsigned long)entry.hdr < table_end) {
> + entry_len = le16_to_cpu(entry.hdr->length);
> +
> + if ((unsigned long)entry.hdr + entry_len > table_end)
> + return -EINVAL;
> +
> + if (entry_len == 0)
> + return -EINVAL;
> +
> + if (cdat_is_subtable_match(&entry)) {
> + rc = call_handler(proc, &entry);
> + if (rc)
> + return rc;
> + count++;
> + }
> +
> + entry.hdr = (struct cdat_entry_header *)((unsigned long)entry.hdr + entry_len);
> + }
> +
> + return count;
> +}
...
> +int cdat_table_parse_sslbis(struct cdat_header *table,
> + cdat_tbl_entry_handler handler, void *arg)
Feels like these ones should take a typed arg. Sure you'll loose
that again to use the generic handling code, but at this level we can
do it I think.
> +{
> + struct cdat_subtable_proc proc = {
> + .handler = handler,
> + .arg = arg,
> + };
> +
> + return cdat_table_parse_entries(CDAT_TYPE_SSLBIS, table, &proc);
> +}
