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soc: mediatek: mtk-cmdq: Add cmdq_pkt_acquire_event() function

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Add cmdq_pkt_acquire_event() function to support CMDQ user making
an instruction for acquiring event.

CMDQ users can use cmdq_pkt_acquire_event() as `mutex_lock`
and cmdq_pkt_clear_event() as `mutex_unlock` to protect the global
resource modified instructions between them.

cmdq_pkt_acquire_event() would wait for event to be cleared.
After event is cleared by cmdq_pkt_clear_event() in other GCE threads,
cmdq_pkt_acquire_event() would set event and keep executing next
instruction. So the mutex would work like this:

    cmdq_pkt_acquire_event() /* mutex lock */

    /* critical secton instructions that modified global resource */

    cmdq_pkt_clear_event() /* mutex unlock */

Prevent the critical section instructions from being affected by other
GCE threads.

Signed-off-by: Jason-JH.Lin <jason-jh.lin@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20240307013458.23550-5-jason-jh.lin@mediatek.com
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
This commit is contained in:
Jason-JH.Lin 2024-03-07 09:34:58 +08:00 committed by AngeloGioacchino Del Regno
parent 400e2fa805
commit 69ff68332d
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GPG Key ID: 9A3604CFAD978478
2 changed files with 30 additions and 0 deletions
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15
drivers/soc/mediatek/mtk-cmdq-helper.c
View File

@ -334,6 +334,21 @@ int cmdq_pkt_wfe(struct cmdq_pkt *pkt, u16 event, bool clear)
}
EXPORT_SYMBOL(cmdq_pkt_wfe);
int cmdq_pkt_acquire_event(struct cmdq_pkt *pkt, u16 event)
{
struct cmdq_instruction inst = {};
if (event >= CMDQ_MAX_EVENT)
return -EINVAL;
inst.op = CMDQ_CODE_WFE;
inst.value = CMDQ_WFE_UPDATE | CMDQ_WFE_UPDATE_VALUE | CMDQ_WFE_WAIT;
inst.event = event;
return cmdq_pkt_append_command(pkt, inst);
}
EXPORT_SYMBOL(cmdq_pkt_acquire_event);
int cmdq_pkt_clear_event(struct cmdq_pkt *pkt, u16 event)
{
struct cmdq_instruction inst = { {0} };

15
include/linux/soc/mediatek/mtk-cmdq.h
View File

@ -206,6 +206,21 @@ int cmdq_pkt_mem_move(struct cmdq_pkt *pkt, dma_addr_t src_addr, dma_addr_t dst_
*/
int cmdq_pkt_wfe(struct cmdq_pkt *pkt, u16 event, bool clear);
/**
* cmdq_pkt_acquire_event() - append acquire event command to the CMDQ packet
* @pkt: the CMDQ packet
* @event: the desired event to be acquired
*
* User can use cmdq_pkt_acquire_event() as `mutex_lock` and cmdq_pkt_clear_event()
* as `mutex_unlock` to protect some `critical section` instructions between them.
* cmdq_pkt_acquire_event() would wait for event to be cleared.
* After event is cleared by cmdq_pkt_clear_event in other GCE threads,
* cmdq_pkt_acquire_event() would set event and keep executing next instruction.
*
* Return: 0 for success; else the error code is returned
*/
int cmdq_pkt_acquire_event(struct cmdq_pkt *pkt, u16 event);
/**
* cmdq_pkt_clear_event() - append clear event command to the CMDQ packet
* @pkt: the CMDQ packet