Marek Vasut <[email protected]> wrote:

> The interrupt handling of the RS911x is particularly heavy. For each RX
> packet, the card does three SDIO transactions, one to read interrupt
> status register, one to RX buffer length, one to read the RX packet(s).
> This translates to ~330 uS per one cycle of interrupt handler. In case
> there is more incoming traffic, this will be more.
> 
> The drivers/mmc/core/sdio_irq.c has the following comment, quote "Just
> like traditional hard IRQ handlers, we expect SDIO IRQ handlers to be
> quick and to the point, so that the holding of the host lock does not
> cover too much work that doesn't require that lock to be held."
> 
> The RS911x interrupt handler does not fit that. This patch therefore
> changes it such that the entire IRQ handler is moved to the RX thread
> instead, and the interrupt handler only wakes the RX thread.
> 
> This is OK, because the interrupt handler only does things which can
> also be done in the RX thread, that is, it checks for firmware loading
> error(s), it checks buffer status, it checks whether a packet arrived
> and if so, reads out the packet and passes it to network stack.
> 
> Moreover, this change permits removal of a code which allocated an
> skbuff only to get 4-byte-aligned buffer, read up to 8kiB of data
> into the skbuff, queue this skbuff into local private queue, then in
> RX thread, this buffer is dequeued, the data in the skbuff as passed
> to the RSI driver core, and the skbuff is deallocated. All this is
> replaced by directly calling the RSI driver core with local buffer.
> 
> Signed-off-by: Marek Vasut <[email protected]>
> Cc: Angus Ainslie <[email protected]>
> Cc: David S. Miller <[email protected]>
> Cc: Jakub Kicinski <[email protected]>
> Cc: Kalle Valo <[email protected]>
> Cc: Lee Jones <[email protected]>
> Cc: Martin Kepplinger <[email protected]>
> Cc: Sebastian Krzyszkowiak <[email protected]>
> Cc: Siva Rebbagondla <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Tested-by: Martin Kepplinger <[email protected]>

2 patches applied to wireless-drivers-next.git, thanks.

287431463e78 rsi: Move card interrupt handling to RX thread
abd131a19f6b rsi: Clean up loop in the interrupt handler

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