This is a note to let you know that I've just added the patch titled
dmaengine: mv_xor_v2: fix tx_submit() implementation
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
dmaengine-mv_xor_v2-fix-tx_submit-implementation.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 44d5887a8bf1e86915c8ff647337cb138149da82 Mon Sep 17 00:00:00 2001
From: Thomas Petazzoni <thomas.petazzoni@xxxxxxxxxxxxxxxxxx>
Date: Fri, 5 May 2017 11:57:48 +0200
Subject: dmaengine: mv_xor_v2: fix tx_submit() implementation
From: Thomas Petazzoni <thomas.petazzoni@xxxxxxxxxxxxxxxxxx>
commit 44d5887a8bf1e86915c8ff647337cb138149da82 upstream.
The mv_xor_v2_tx_submit() gets the next available HW descriptor by
calling mv_xor_v2_get_desq_write_ptr(), which reads a HW register
telling the next available HW descriptor. This was working fine when HW
descriptors were issued for processing directly in tx_submit().
However, as part of the review process of the driver, a change was
requested to move the actual kick-off of HW descriptors processing to
->issue_pending(). Due to this, reading the HW register to know the next
available HW descriptor no longer works.
So instead of using this HW register, we implemented a software index
pointing to the next available HW descriptor.
Fixes: 19a340b1a820 ("dmaengine: mv_xor_v2: new driver")
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Vinod Koul <vinod.koul@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/dma/mv_xor_v2.c | 22 +++++-----------------
1 file changed, 5 insertions(+), 17 deletions(-)
--- a/drivers/dma/mv_xor_v2.c
+++ b/drivers/dma/mv_xor_v2.c
@@ -161,6 +161,7 @@ struct mv_xor_v2_device {
struct mv_xor_v2_sw_desc *sw_desq;
int desc_size;
unsigned int npendings;
+ unsigned int hw_queue_idx;
};
/**
@@ -214,18 +215,6 @@ static void mv_xor_v2_set_data_buffers(s
}
/*
- * Return the next available index in the DESQ.
- */
-static int mv_xor_v2_get_desq_write_ptr(struct mv_xor_v2_device *xor_dev)
-{
- /* read the index for the next available descriptor in the DESQ */
- u32 reg = readl(xor_dev->dma_base + MV_XOR_V2_DMA_DESQ_ALLOC_OFF);
-
- return ((reg >> MV_XOR_V2_DMA_DESQ_ALLOC_WRPTR_SHIFT)
- & MV_XOR_V2_DMA_DESQ_ALLOC_WRPTR_MASK);
-}
-
-/*
* notify the engine of new descriptors, and update the available index.
*/
static void mv_xor_v2_add_desc_to_desq(struct mv_xor_v2_device *xor_dev,
@@ -306,7 +295,6 @@ static irqreturn_t mv_xor_v2_interrupt_h
static dma_cookie_t
mv_xor_v2_tx_submit(struct dma_async_tx_descriptor *tx)
{
- int desq_ptr;
void *dest_hw_desc;
dma_cookie_t cookie;
struct mv_xor_v2_sw_desc *sw_desc =
@@ -322,15 +310,15 @@ mv_xor_v2_tx_submit(struct dma_async_tx_
spin_lock_bh(&xor_dev->lock);
cookie = dma_cookie_assign(tx);
- /* get the next available slot in the DESQ */
- desq_ptr = mv_xor_v2_get_desq_write_ptr(xor_dev);
-
/* copy the HW descriptor from the SW descriptor to the DESQ */
- dest_hw_desc = xor_dev->hw_desq_virt + desq_ptr;
+ dest_hw_desc = xor_dev->hw_desq_virt + xor_dev->hw_queue_idx;
memcpy(dest_hw_desc, &sw_desc->hw_desc, xor_dev->desc_size);
xor_dev->npendings++;
+ xor_dev->hw_queue_idx++;
+ if (xor_dev->hw_queue_idx >= MV_XOR_V2_DESC_NUM)
+ xor_dev->hw_queue_idx = 0;
spin_unlock_bh(&xor_dev->lock);
Patches currently in stable-queue which might be from thomas.petazzoni@xxxxxxxxxxxxxxxxxx are
queue-4.9/dmaengine-mv_xor_v2-properly-handle-wrapping-in-the-array-of-hw-descriptors.patch
queue-4.9/dmaengine-mv_xor_v2-enable-xor-engine-after-its-configuration.patch
queue-4.9/dmaengine-mv_xor_v2-set-dma-mask-to-40-bits.patch
queue-4.9/dmaengine-mv_xor_v2-do-not-use-descriptors-not-acked-by-async_tx.patch
queue-4.9/dmaengine-mv_xor_v2-handle-mv_xor_v2_prep_sw_desc-error-properly.patch
queue-4.9/dmaengine-mv_xor_v2-remove-interrupt-coalescing.patch
queue-4.9/dmaengine-mv_xor_v2-fix-tx_submit-implementation.patch