bcm2836-mbox: last_tx_done should wait for handling on remote side

pietrushnic / rpi-dt-linux

This repository aims to handle all patches required for Raspberry Pi support in upstream Linux kernel.

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bcm2836-mbox: last_tx_done should wait for handling on remote side #3

Closed pietrushnic closed 9 years ago

pietrushnic commented 9 years ago

Previous code tried to verify if VPU->ARM (MAIL0) receiving queue is empty after submitting message to ARM->VPU (MAIL1) queue. This patch change mailbox used in last_tx_done to MAIL1.

Based on IRC advice from Ross Oldfield.

Signed-off-by: Piotr Król piotr.krol@3mdeb.com

pietrushnic commented 9 years ago

@rossoldfield please review. Especially letm me know if commit message is ok for you.

rossoldfield commented 9 years ago

Unsure about line 114: if (readl(mbox->regs + MAIL0_STA) & ARM_MS_FULL) { rmb(); /* Finished last mailbox read. */ ret = -EBUSY;

I don't think this can ever be true because the FIFO is 8 entries deep and we only process a single 32-bit value per transaction.