From baa914cd81f51f4e4f3bae5bb59764b32ad8c353 Mon Sep 17 00:00:00 2001 From: Takashi Sakamoto Date: Tue, 5 Apr 2022 16:22:20 +0900 Subject: firewire: add kernel API to access CYCLE_TIME register 1394 OHCI specification defined Isochronous Cycle Timer Register to get value of CYCLE_TIME register defined by IEEE 1394 for CSR architecture defined by ISO/IEC 13213. Unit driver can calculate packet time by compute with the value of CYCLE_TIME and timeStamp field in descriptor of each isochronous and asynchronous context. The resolution of CYCLE_TIME is 49.576 MHz, while the one of timeStamp is 8,000 Hz. Current implementation of Linux FireWire subsystem allows the driver to get the value of CYCLE_TIMER CSR register by transaction service. The transaction service has overhead in regard of access to MMIO register. This commit adds kernel API for unit driver to access the register directly. Signed-off-by: Takashi Sakamoto Link: https://lore.kernel.org/r/20220405072221.226217-3-o-takashi@sakamocchi.jp Signed-off-by: Takashi Iwai --- include/linux/firewire.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux/firewire.h') diff --git a/include/linux/firewire.h b/include/linux/firewire.h index 07967a450eaa..2f467c52bdec 100644 --- a/include/linux/firewire.h +++ b/include/linux/firewire.h @@ -150,6 +150,8 @@ static inline void fw_card_put(struct fw_card *card) kref_put(&card->kref, fw_card_release); } +int fw_card_read_cycle_time(struct fw_card *card, u32 *cycle_time); + struct fw_attribute_group { struct attribute_group *groups[2]; struct attribute_group group; -- cgit v1.2.3 From b2405aa948b95afc5246fa56fc05c3512cd6185c Mon Sep 17 00:00:00 2001 From: Takashi Sakamoto Date: Tue, 5 Apr 2022 16:22:21 +0900 Subject: firewire: add kernel API to access packet structure in request structure for AR context In 1394 OHCI specification, descriptor of Asynchronous Receive DMA context has timeStamp field in its trailer quadlet. The field is written by the host controller for the time to receive asynchronous request subaction in isochronous cycle time. In Linux FireWire subsystem, the value of field is stored to fw_packet structure and copied to fw_request structure as the part. The fw_request structure is hidden from unit driver and passed as opaque pointer when calling registered handler. It's inconvenient to the unit driver which needs timestamp of packet. This commit adds kernel API to pick up timestamp from opaque pointer to fw_request structure. Signed-off-by: Takashi Sakamoto Link: https://lore.kernel.org/r/20220405072221.226217-4-o-takashi@sakamocchi.jp Signed-off-by: Takashi Iwai --- include/linux/firewire.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/firewire.h') diff --git a/include/linux/firewire.h b/include/linux/firewire.h index 2f467c52bdec..980019053e54 100644 --- a/include/linux/firewire.h +++ b/include/linux/firewire.h @@ -354,6 +354,7 @@ void fw_core_remove_address_handler(struct fw_address_handler *handler); void fw_send_response(struct fw_card *card, struct fw_request *request, int rcode); int fw_get_request_speed(struct fw_request *request); +u32 fw_request_get_timestamp(const struct fw_request *request); void fw_send_request(struct fw_card *card, struct fw_transaction *t, int tcode, int destination_id, int generation, int speed, unsigned long long offset, void *payload, size_t length, -- cgit v1.2.3