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authorTakashi Sakamoto <o-takashi@sakamocchi.jp>2023-05-30 08:12:40 +0900
committerTakashi Sakamoto <o-takashi@sakamocchi.jp>2023-05-30 08:12:40 +0900
commitdcadfd7f7c74ef9ee415e072a19bdf6c085159eb (patch)
tree972c117afc5f9f5f066302457096449e35e63321 /drivers/firewire/core.h
parent865efffb2d11402bc6f96c7e390b89384e9d209d (diff)
firewire: core: use union for callback of transaction completion
In 1394 OHCI, the OUTPUT_LAST descriptor of Asynchronous Transmit (AT) request context has timeStamp field, in which 1394 OHCI controller record the isochronous cycle when the packet was sent for the request subaction. Additionally, for the case of split transaction in IEEE 1394, Asynchronous Receive (AT) request context is used for response subaction to finish the transaction. The trailer quadlet of descriptor in the context has timeStamp field, in which 1394 OHCI controller records the isochronous cycle when the packet arrived. Current implementation of 1394 OHCI controller driver stores values of both fields to internal structure as time stamp, while Linux FireWire subsystem provides no way to access to it. When using asynchronous transaction service provided by the subsystem, callback function is passed to kernel API. The prototype of callback function has the lack of argument for the values. This commit adds a new callback function for the purpose. It has an additional argument to point to the constant array with two elements. For backward compatibility to kernel space, a new union is also adds to wrap two different prototype of callback function. The fw_transaction structure has the union as a member and a boolean flag to express which function callback is available. The core function is changed to handle the two cases; with or without time stamp. For the error path to process transaction, the isochronous cycle is computed by current value of CYCLE_TIMER register in 1394 OHCI controller. Especially for the case of timeout of split transaction, the expected isochronous cycle is computed. Link: https://lore.kernel.org/r/20230529113406.986289-6-o-takashi@sakamocchi.jp Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Diffstat (limited to 'drivers/firewire/core.h')
-rw-r--r--drivers/firewire/core.h7
1 files changed, 7 insertions, 0 deletions
diff --git a/drivers/firewire/core.h b/drivers/firewire/core.h
index eafa4eaae737..2a05f411328f 100644
--- a/drivers/firewire/core.h
+++ b/drivers/firewire/core.h
@@ -247,6 +247,13 @@ void fw_fill_response(struct fw_packet *response, u32 *request_header,
void fw_request_get(struct fw_request *request);
void fw_request_put(struct fw_request *request);
+// Convert the value of IEEE 1394 CYCLE_TIME register to the format of timeStamp field in
+// descriptors of 1394 OHCI.
+static inline u32 cycle_time_to_ohci_tstamp(u32 tstamp)
+{
+ return (tstamp & 0x0ffff000) >> 12;
+}
+
#define FW_PHY_CONFIG_NO_NODE_ID -1
#define FW_PHY_CONFIG_CURRENT_GAP_COUNT -1
void fw_send_phy_config(struct fw_card *card,