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MLK-24825-1: dmaengine: fsl-edma-v3: checking ACTIVE bit for channel stop 

Checking ACTIVE bit to ensure channel stop indeed, otherwise, there is risk
that illegal memory touch after channel not stopped with buffer freed. Only
fix on rx channel.

Signed-off-by: Robin Gong <yibin.gong@nxp.com>
Reviewed-by: Fugang Duan <fugang.duan@nxp.com>
This commit is contained in:
Robin Gong 2020-09-22 02:19:47 +08:00
parent 9b8509a9ea
commit ed1ff2a449
1 changed files with 16 additions and 1 deletions
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17
drivers/dma/fsl-edma-v3.c
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@ -17,6 +17,7 @@
#include <linux/init.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/iopoll.h>
#include <linux/clk.h>
#include <linux/dma-mapping.h>
#include <linux/dmapool.h>
@ -113,6 +114,8 @@
#define CHAN_PREFIX "edma0-chan"
#define CHAN_POSFIX "-tx"
#define EDMA_MINOR_LOOP_TIMEOUT 500 /* us */
enum fsl_edma3_pm_state {
RUNNING = 0,
SUSPENDED,
@ -284,9 +287,21 @@ static int fsl_edma3_terminate_all(struct dma_chan *chan)
struct fsl_edma3_chan *fsl_chan = to_fsl_edma3_chan(chan);
unsigned long flags;
LIST_HEAD(head);
u32 val;
fsl_edma3_disable_request(fsl_chan);
/*
* Checking ACTIVE to ensure minor loop stop indeed to prevent the
* potential illegal memory write if channel not stopped with buffer
* freed. Ignore tx channel since no such risk.
*/
if (fsl_chan->is_rxchan)
readl_poll_timeout_atomic(fsl_chan->membase + EDMA_CH_CSR, val,
!(val & EDMA_CH_CSR_ACTIVE), 2,
EDMA_MINOR_LOOP_TIMEOUT);
spin_lock_irqsave(&fsl_chan->vchan.lock, flags);
fsl_edma3_disable_request(fsl_chan);
fsl_chan->edesc = NULL;
fsl_chan->idle = true;
fsl_chan->used = false;