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author | Takashi Sakamoto <o-takashi@sakamocchi.jp> | 2023-05-30 08:12:40 +0900 |
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committer | Takashi Sakamoto <o-takashi@sakamocchi.jp> | 2023-05-30 08:12:40 +0900 |
commit | dcadfd7f7c74ef9ee415e072a19bdf6c085159eb (patch) | |
tree | 972c117afc5f9f5f066302457096449e35e63321 /drivers/firewire/core.h | |
parent | 865efffb2d11402bc6f96c7e390b89384e9d209d (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.h | 7 |
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, |