[PATCH v2 1/2] firmware: arm_scmi: Add support for multiple vendors custom protocols
Cristian Marussi
cristian.marussi at arm.com
Mon Apr 8 02:30:51 PDT 2024
Add a mechanism to be able to tag vendor protocol modules at compile-time
with a vendor/sub_vendor string and an implementation version and then to
choose to load, at run-time, only those vendor protocol modules matching
as close as possible the vendor/subvendor identification advertised by
the SCMI platform server.
In this way, any in-tree existent vendor protocol module can be build and
shipped by default in a single kernel image, even when using the same
clashing protocol identification numbers, since the SCMI core will take
care at run-time to load only the ones pertinent to the running system.
Signed-off-by: Cristian Marussi <cristian.marussi at arm.com>
---
drivers/firmware/arm_scmi/driver.c | 165 ++++++++++++++++++++++----
drivers/firmware/arm_scmi/protocols.h | 15 +++
2 files changed, 158 insertions(+), 22 deletions(-)
diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c
index d0091459a276..aa18202054a5 100644
--- a/drivers/firmware/arm_scmi/driver.c
+++ b/drivers/firmware/arm_scmi/driver.c
@@ -33,6 +33,7 @@
#include <linux/processor.h>
#include <linux/refcount.h>
#include <linux/slab.h>
+#include <linux/xarray.h>
#include "common.h"
#include "notify.h"
@@ -44,8 +45,7 @@
static DEFINE_IDA(scmi_id);
-static DEFINE_IDR(scmi_protocols);
-static DEFINE_SPINLOCK(protocol_lock);
+static DEFINE_XARRAY(scmi_protocols);
/* List of all SCMI devices active in system */
static LIST_HEAD(scmi_list);
@@ -194,11 +194,90 @@ struct scmi_info {
#define bus_nb_to_scmi_info(nb) container_of(nb, struct scmi_info, bus_nb)
#define req_nb_to_scmi_info(nb) container_of(nb, struct scmi_info, dev_req_nb)
-static const struct scmi_protocol *scmi_protocol_get(int protocol_id)
+static unsigned long
+scmi_vendor_protocol_signature(unsigned int protocol_id, char *vendor_id,
+ char *sub_vendor_id, u32 impl_ver)
{
- const struct scmi_protocol *proto;
+ char *signature, *p;
+ unsigned long hash = 0;
- proto = idr_find(&scmi_protocols, protocol_id);
+ /* vendor_id/sub_vendor_id guaranteed <= SCMI_SHORT_NAME_MAX_SIZE */
+ signature = kasprintf(GFP_KERNEL, "%02X|%s|%s|0x%08X", protocol_id,
+ vendor_id ?: "", sub_vendor_id ?: "", impl_ver);
+ if (!signature)
+ return 0;
+
+ p = signature;
+ while (*p)
+ hash = partial_name_hash(tolower(*p++), hash);
+ hash = end_name_hash(hash);
+
+ kfree(signature);
+
+ return hash;
+}
+
+static unsigned long
+scmi_protocol_key_calculate(int protocol_id, char *vendor_id,
+ char *sub_vendor_id, u32 impl_ver)
+{
+ if (protocol_id < SCMI_PROTOCOL_VENDOR)
+ return protocol_id;
+ else
+ return scmi_vendor_protocol_signature(protocol_id, vendor_id,
+ sub_vendor_id, impl_ver);
+}
+
+static const struct scmi_protocol *
+scmi_vendor_protocol_lookup(int protocol_id, char *vendor_id,
+ char *sub_vendor_id, u32 impl_ver)
+{
+ unsigned long key;
+ struct scmi_protocol *proto = NULL;
+
+ /* Searching for closest match ...*/
+ key = scmi_protocol_key_calculate(protocol_id, vendor_id,
+ sub_vendor_id, impl_ver);
+ if (key)
+ proto = xa_load(&scmi_protocols, key);
+
+ if (proto)
+ return proto;
+
+ /* Any match on vendor/sub_vendor ? */
+ if (impl_ver) {
+ key = scmi_protocol_key_calculate(protocol_id, vendor_id,
+ sub_vendor_id, 0);
+ if (key)
+ proto = xa_load(&scmi_protocols, key);
+
+ if (proto)
+ return proto;
+ }
+
+ /* Any match on just the vendor ? */
+ if (sub_vendor_id) {
+ key = scmi_protocol_key_calculate(protocol_id, vendor_id,
+ NULL, 0);
+ if (key)
+ proto = xa_load(&scmi_protocols, key);
+ }
+
+ return proto;
+}
+
+static const struct scmi_protocol *
+scmi_protocol_get(int protocol_id, struct scmi_revision_info *version)
+{
+ const struct scmi_protocol *proto = NULL;
+
+ if (protocol_id < SCMI_PROTOCOL_VENDOR)
+ proto = xa_load(&scmi_protocols, protocol_id);
+ else
+ proto = scmi_vendor_protocol_lookup(protocol_id,
+ version->vendor_id,
+ version->sub_vendor_id,
+ version->impl_ver);
if (!proto || !try_module_get(proto->owner)) {
pr_warn("SCMI Protocol 0x%x not found!\n", protocol_id);
return NULL;
@@ -206,21 +285,46 @@ static const struct scmi_protocol *scmi_protocol_get(int protocol_id)
pr_debug("Found SCMI Protocol 0x%x\n", protocol_id);
+ if (protocol_id >= SCMI_PROTOCOL_VENDOR)
+ pr_info("Loaded SCMI Vendor Protocol 0x%x - %s %s %X\n",
+ protocol_id, proto->vendor_id ?: "",
+ proto->sub_vendor_id ?: "", proto->impl_ver);
+
return proto;
}
-static void scmi_protocol_put(int protocol_id)
+static void scmi_protocol_put(const struct scmi_protocol *proto)
{
- const struct scmi_protocol *proto;
-
- proto = idr_find(&scmi_protocols, protocol_id);
if (proto)
module_put(proto->owner);
}
+static int scmi_vendor_protocol_check(const struct scmi_protocol *proto)
+{
+ if (!proto->vendor_id) {
+ pr_err("missing vendor_id for protocol 0x%x\n", proto->id);
+ return -EINVAL;
+ }
+
+ if (strlen(proto->vendor_id) >= SCMI_SHORT_NAME_MAX_SIZE) {
+ pr_err("malformed vendor_id for protocol 0x%x\n", proto->id);
+ return -EINVAL;
+ }
+
+ if (proto->sub_vendor_id &&
+ strlen(proto->sub_vendor_id) >= SCMI_SHORT_NAME_MAX_SIZE) {
+ pr_err("malformed sub_vendor_id for protocol 0x%x\n",
+ proto->id);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
int scmi_protocol_register(const struct scmi_protocol *proto)
{
int ret;
+ unsigned long key;
if (!proto) {
pr_err("invalid protocol\n");
@@ -232,12 +336,23 @@ int scmi_protocol_register(const struct scmi_protocol *proto)
return -EINVAL;
}
- spin_lock(&protocol_lock);
- ret = idr_alloc(&scmi_protocols, (void *)proto,
- proto->id, proto->id + 1, GFP_ATOMIC);
- spin_unlock(&protocol_lock);
- if (ret != proto->id) {
- pr_err("unable to allocate SCMI idr slot for 0x%x - err %d\n",
+ if (proto->id >= SCMI_PROTOCOL_VENDOR &&
+ scmi_vendor_protocol_check(proto))
+ return -EINVAL;
+
+ /*
+ * Calculate a protocol key to register this protocol with the core;
+ * key value 0 is considered invalid.
+ */
+ key = scmi_protocol_key_calculate(proto->id, proto->vendor_id,
+ proto->sub_vendor_id,
+ proto->impl_ver);
+ if (!key)
+ return -EINVAL;
+
+ ret = xa_insert(&scmi_protocols, key, (void *)proto, GFP_KERNEL);
+ if (ret) {
+ pr_err("unable to allocate SCMI protocol slot for 0x%x - err %d\n",
proto->id, ret);
return ret;
}
@@ -250,9 +365,15 @@ EXPORT_SYMBOL_GPL(scmi_protocol_register);
void scmi_protocol_unregister(const struct scmi_protocol *proto)
{
- spin_lock(&protocol_lock);
- idr_remove(&scmi_protocols, proto->id);
- spin_unlock(&protocol_lock);
+ unsigned long key;
+
+ key = scmi_protocol_key_calculate(proto->id, proto->vendor_id,
+ proto->sub_vendor_id,
+ proto->impl_ver);
+ if (!key)
+ return;
+
+ xa_erase(&scmi_protocols, key);
pr_debug("Unregistered SCMI Protocol 0x%x\n", proto->id);
}
@@ -1940,7 +2061,7 @@ scmi_alloc_init_protocol_instance(struct scmi_info *info,
/* Protocol specific devres group */
gid = devres_open_group(handle->dev, NULL, GFP_KERNEL);
if (!gid) {
- scmi_protocol_put(proto->id);
+ scmi_protocol_put(proto);
goto out;
}
@@ -2004,7 +2125,7 @@ scmi_alloc_init_protocol_instance(struct scmi_info *info,
clean:
/* Take care to put the protocol module's owner before releasing all */
- scmi_protocol_put(proto->id);
+ scmi_protocol_put(proto);
devres_release_group(handle->dev, gid);
out:
return ERR_PTR(ret);
@@ -2038,7 +2159,7 @@ scmi_get_protocol_instance(const struct scmi_handle *handle, u8 protocol_id)
const struct scmi_protocol *proto;
/* Fails if protocol not registered on bus */
- proto = scmi_protocol_get(protocol_id);
+ proto = scmi_protocol_get(protocol_id, &info->version);
if (proto)
pi = scmi_alloc_init_protocol_instance(info, proto);
else
@@ -2093,7 +2214,7 @@ void scmi_protocol_release(const struct scmi_handle *handle, u8 protocol_id)
idr_remove(&info->protocols, protocol_id);
- scmi_protocol_put(protocol_id);
+ scmi_protocol_put(pi->proto);
devres_release_group(handle->dev, gid);
dev_dbg(handle->dev, "De-Initialized protocol: 0x%X\n",
diff --git a/drivers/firmware/arm_scmi/protocols.h b/drivers/firmware/arm_scmi/protocols.h
index 317d3fb32676..45ee8b35f56d 100644
--- a/drivers/firmware/arm_scmi/protocols.h
+++ b/drivers/firmware/arm_scmi/protocols.h
@@ -29,6 +29,8 @@
#define PROTOCOL_REV_MAJOR(x) ((u16)(FIELD_GET(PROTOCOL_REV_MAJOR_MASK, (x))))
#define PROTOCOL_REV_MINOR(x) ((u16)(FIELD_GET(PROTOCOL_REV_MINOR_MASK, (x))))
+#define SCMI_PROTOCOL_VENDOR 0x80
+
enum scmi_common_cmd {
PROTOCOL_VERSION = 0x0,
PROTOCOL_ATTRIBUTES = 0x1,
@@ -323,6 +325,16 @@ typedef int (*scmi_prot_init_ph_fn_t)(const struct scmi_protocol_handle *);
* protocol by the agent. Each protocol implementation
* in the agent is supposed to downgrade to match the
* protocol version supported by the platform.
+ * @vendor_id: A firmware vendor string for vendor protocols matching.
+ * Ignored when @id identifies a standard protocol, cannot be NULL
+ * otherwise.
+ * @sub_vendor_id: A firmware sub_vendor string for vendor protocols matching.
+ * Ignored if NULL or when @id identifies a standard protocol.
+ * @impl_ver: A firmware implementation version for vendor protocols matching.
+ * Ignored if zero or if @id identifies a standard protocol.
+ *
+ * Note that vendor protocols matching at load time is performed by attempting
+ * the closest match first against the tuple (vendor, sub_vendor, impl_ver)
*/
struct scmi_protocol {
const u8 id;
@@ -332,6 +344,9 @@ struct scmi_protocol {
const void *ops;
const struct scmi_protocol_events *events;
unsigned int supported_version;
+ char *vendor_id;
+ char *sub_vendor_id;
+ u32 impl_ver;
};
#define DEFINE_SCMI_PROTOCOL_REGISTER_UNREGISTER(name, proto) \
--
2.44.0
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