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68 lines
2.0 KiB
68 lines
2.0 KiB
From a2dd154377c9aa6ddda00d39b8c7c334e4fa16ff Mon Sep 17 00:00:00 2001
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From: Damien Horsley <damien.horsley@imgtec.com>
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Date: Tue, 22 Mar 2016 12:46:09 +0000
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Subject: dmaengine: img-mdc: Handle early status read
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It is possible that mdc_tx_status may be called before the first
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node has been read from memory.
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In this case, the residue value stored in the register is undefined.
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Return the transfer size instead.
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Signed-off-by: Damien Horsley <damien.horsley@imgtec.com>
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---
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drivers/dma/img-mdc-dma.c | 40 ++++++++++++++++++++++++----------------
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1 file changed, 24 insertions(+), 16 deletions(-)
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--- a/drivers/dma/img-mdc-dma.c
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+++ b/drivers/dma/img-mdc-dma.c
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@@ -620,25 +620,33 @@ static enum dma_status mdc_tx_status(str
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(MDC_CMDS_PROCESSED_CMDS_DONE_MASK + 1);
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/*
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- * If the command loaded event hasn't been processed yet, then
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- * the difference above includes an extra command.
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+ * If the first node has not yet been read from memory,
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+ * the residue register value is undefined
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*/
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- if (!mdesc->cmd_loaded)
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- cmds--;
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- else
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- cmds += mdesc->list_cmds_done;
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-
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- bytes = mdesc->list_xfer_size;
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- ldesc = mdesc->list;
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- for (i = 0; i < cmds; i++) {
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- bytes -= ldesc->xfer_size + 1;
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- ldesc = ldesc->next_desc;
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- }
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- if (ldesc) {
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- if (residue != MDC_TRANSFER_SIZE_MASK)
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- bytes -= ldesc->xfer_size - residue;
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+ if (!mdesc->cmd_loaded && !cmds) {
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+ bytes = mdesc->list_xfer_size;
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+ } else {
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+ /*
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+ * If the command loaded event hasn't been processed yet, then
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+ * the difference above includes an extra command.
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+ */
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+ if (!mdesc->cmd_loaded)
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+ cmds--;
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else
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+ cmds += mdesc->list_cmds_done;
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+
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+ bytes = mdesc->list_xfer_size;
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+ ldesc = mdesc->list;
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+ for (i = 0; i < cmds; i++) {
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bytes -= ldesc->xfer_size + 1;
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+ ldesc = ldesc->next_desc;
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+ }
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+ if (ldesc) {
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+ if (residue != MDC_TRANSFER_SIZE_MASK)
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+ bytes -= ldesc->xfer_size - residue;
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+ else
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+ bytes -= ldesc->xfer_size + 1;
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+ }
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}
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}
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spin_unlock_irqrestore(&mchan->vc.lock, flags);
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