dmaengine: at_hdmac: replace spin_lock* with irqsave variants

dmaengine routines can be called from interrupt context and with
interrupts disabled. Whereas spin_unlock_bh can't be called from
such contexts. So this patch converts all spin_lock* routines
to irqsave variants.

Also, spin_lock() used in tasklet is converted to irqsave variants,
as tasklet can be interrupted, and dma requests from such interruptions
may also call spin_lock.

Idea from dw_dmac patch by Viresh Kumar.

Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

1 files changed, 30 insertions, 22 deletions

diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c
index 6a483eac7b3f..fd87b9690e1b 100644
--- a/drivers/dma/at_hdmac.c
+++ b/drivers/dma/at_hdmac.c
@@ -107,10 +107,11 @@ static struct at_desc *atc_desc_get(struct at_dma_chan *atchan)
 {
         struct at_desc *desc, *_desc;
         struct at_desc *ret = NULL;
+        unsigned long flags;
         unsigned int i = 0;
         LIST_HEAD(tmp_list);
 
-        spin_lock_bh(&atchan->lock);
+        spin_lock_irqsave(&atchan->lock, flags);
         list_for_each_entry_safe(desc, _desc, &atchan->free_list, desc_node) {
                 i++;
                 if (async_tx_test_ack(&desc->txd)) {
@@ -121,7 +122,7 @@ static struct at_desc *atc_desc_get(struct at_dma_chan *atchan)
                 dev_dbg(chan2dev(&atchan->chan_common),
                                 "desc %p not ACKed\n", desc);
         }
-        spin_unlock_bh(&atchan->lock);
+        spin_unlock_irqrestore(&atchan->lock, flags);
         dev_vdbg(chan2dev(&atchan->chan_common),
                 "scanned %u descriptors on freelist\n", i);
 
@@ -129,9 +130,9 @@ static struct at_desc *atc_desc_get(struct at_dma_chan *atchan)
         if (!ret) {
                 ret = atc_alloc_descriptor(&atchan->chan_common, GFP_ATOMIC);
                 if (ret) {
-                        spin_lock_bh(&atchan->lock);
+                        spin_lock_irqsave(&atchan->lock, flags);
                         atchan->descs_allocated++;
-                        spin_unlock_bh(&atchan->lock);
+                        spin_unlock_irqrestore(&atchan->lock, flags);
                 } else {
                         dev_err(chan2dev(&atchan->chan_common),
                                         "not enough descriptors available\n");
@@ -150,8 +151,9 @@ static void atc_desc_put(struct at_dma_chan *atchan, struct at_desc *desc)
 {
         if (desc) {
                 struct at_desc *child;
+                unsigned long flags;
 
-                spin_lock_bh(&atchan->lock);
+                spin_lock_irqsave(&atchan->lock, flags);
                 list_for_each_entry(child, &desc->tx_list, desc_node)
                         dev_vdbg(chan2dev(&atchan->chan_common),
                                         "moving child desc %p to freelist\n",
@@ -160,7 +162,7 @@ static void atc_desc_put(struct at_dma_chan *atchan, struct at_desc *desc)
                 dev_vdbg(chan2dev(&atchan->chan_common),
                          "moving desc %p to freelist\n", desc);
                 list_add(&desc->desc_node, &atchan->free_list);
-                spin_unlock_bh(&atchan->lock);
+                spin_unlock_irqrestore(&atchan->lock, flags);
         }
 }
 
@@ -471,8 +473,9 @@ static void atc_handle_cyclic(struct at_dma_chan *atchan)
 static void atc_tasklet(unsigned long data)
 {
         struct at_dma_chan *atchan = (struct at_dma_chan *)data;
+        unsigned long flags;
 
-        spin_lock(&atchan->lock);
+        spin_lock_irqsave(&atchan->lock, flags);
         if (test_and_clear_bit(ATC_IS_ERROR, &atchan->status))
                 atc_handle_error(atchan);
         else if (test_bit(ATC_IS_CYCLIC, &atchan->status))
@@ -480,7 +483,7 @@ static void atc_tasklet(unsigned long data)
         else
                 atc_advance_work(atchan);
 
-        spin_unlock(&atchan->lock);
+        spin_unlock_irqrestore(&atchan->lock, flags);
 }
 
 static irqreturn_t at_dma_interrupt(int irq, void *dev_id)
@@ -539,8 +542,9 @@ static dma_cookie_t atc_tx_submit(struct dma_async_tx_descriptor *tx)
         struct at_desc          *desc = txd_to_at_desc(tx);
         struct at_dma_chan      *atchan = to_at_dma_chan(tx->chan);
         dma_cookie_t            cookie;
+        unsigned long           flags;
 
-        spin_lock_bh(&atchan->lock);
+        spin_lock_irqsave(&atchan->lock, flags);
         cookie = atc_assign_cookie(atchan, desc);
 
         if (list_empty(&atchan->active_list)) {
@@ -554,7 +558,7 @@ static dma_cookie_t atc_tx_submit(struct dma_async_tx_descriptor *tx)
                 list_add_tail(&desc->desc_node, &atchan->queue);
         }
 
-        spin_unlock_bh(&atchan->lock);
+        spin_unlock_irqrestore(&atchan->lock, flags);
 
         return cookie;
 }
@@ -927,28 +931,29 @@ static int atc_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
         struct at_dma_chan      *atchan = to_at_dma_chan(chan);
         struct at_dma           *atdma = to_at_dma(chan->device);
         int                     chan_id = atchan->chan_common.chan_id;
+        unsigned long           flags;
 
         LIST_HEAD(list);
 
         dev_vdbg(chan2dev(chan), "atc_control (%d)\n", cmd);
 
         if (cmd == DMA_PAUSE) {
-                spin_lock_bh(&atchan->lock);
+                spin_lock_irqsave(&atchan->lock, flags);
 
                 dma_writel(atdma, CHER, AT_DMA_SUSP(chan_id));
                 set_bit(ATC_IS_PAUSED, &atchan->status);
 
-                spin_unlock_bh(&atchan->lock);
+                spin_unlock_irqrestore(&atchan->lock, flags);
         } else if (cmd == DMA_RESUME) {
                 if (!test_bit(ATC_IS_PAUSED, &atchan->status))
                         return 0;
 
-                spin_lock_bh(&atchan->lock);
+                spin_lock_irqsave(&atchan->lock, flags);
 
                 dma_writel(atdma, CHDR, AT_DMA_RES(chan_id));
                 clear_bit(ATC_IS_PAUSED, &atchan->status);
 
-                spin_unlock_bh(&atchan->lock);
+                spin_unlock_irqrestore(&atchan->lock, flags);
         } else if (cmd == DMA_TERMINATE_ALL) {
                 struct at_desc  *desc, *_desc;
                 /*
@@ -957,7 +962,7 @@ static int atc_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
                  * channel. We still have to poll the channel enable bit due
                  * to AHB/HSB limitations.
                  */
-                spin_lock_bh(&atchan->lock);
+                spin_lock_irqsave(&atchan->lock, flags);
 
                 /* disabling channel: must also remove suspend state */
                 dma_writel(atdma, CHDR, AT_DMA_RES(chan_id) | atchan->mask);
@@ -978,7 +983,7 @@ static int atc_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
                 /* if channel dedicated to cyclic operations, free it */
                 clear_bit(ATC_IS_CYCLIC, &atchan->status);
 
-                spin_unlock_bh(&atchan->lock);
+                spin_unlock_irqrestore(&atchan->lock, flags);
         } else {
                 return -ENXIO;
         }
@@ -1004,9 +1009,10 @@ atc_tx_status(struct dma_chan *chan,
         struct at_dma_chan      *atchan = to_at_dma_chan(chan);
         dma_cookie_t            last_used;
         dma_cookie_t            last_complete;
+        unsigned long           flags;
         enum dma_status         ret;
 
-        spin_lock_bh(&atchan->lock);
+        spin_lock_irqsave(&atchan->lock, flags);
 
         last_complete = atchan->completed_cookie;
         last_used = chan->cookie;
@@ -1021,7 +1027,7 @@ atc_tx_status(struct dma_chan *chan,
                 ret = dma_async_is_complete(cookie, last_complete, last_used);
         }
 
-        spin_unlock_bh(&atchan->lock);
+        spin_unlock_irqrestore(&atchan->lock, flags);
 
         if (ret != DMA_SUCCESS)
                 dma_set_tx_state(txstate, last_complete, last_used,
@@ -1046,6 +1052,7 @@ atc_tx_status(struct dma_chan *chan,
 static void atc_issue_pending(struct dma_chan *chan)
 {
         struct at_dma_chan      *atchan = to_at_dma_chan(chan);
+        unsigned long           flags;
 
         dev_vdbg(chan2dev(chan), "issue_pending\n");
 
@@ -1053,11 +1060,11 @@ static void atc_issue_pending(struct dma_chan *chan)
         if (test_bit(ATC_IS_CYCLIC, &atchan->status))
                 return;
 
-        spin_lock_bh(&atchan->lock);
+        spin_lock_irqsave(&atchan->lock, flags);
         if (!atc_chan_is_enabled(atchan)) {
                 atc_advance_work(atchan);
         }
-        spin_unlock_bh(&atchan->lock);
+        spin_unlock_irqrestore(&atchan->lock, flags);
 }
 
 /**
@@ -1073,6 +1080,7 @@ static int atc_alloc_chan_resources(struct dma_chan *chan)
         struct at_dma           *atdma = to_at_dma(chan->device);
         struct at_desc          *desc;
         struct at_dma_slave     *atslave;
+        unsigned long           flags;
         int                     i;
         u32                     cfg;
         LIST_HEAD(tmp_list);
@@ -1116,11 +1124,11 @@ static int atc_alloc_chan_resources(struct dma_chan *chan)
                 list_add_tail(&desc->desc_node, &tmp_list);
         }
 
-        spin_lock_bh(&atchan->lock);
+        spin_lock_irqsave(&atchan->lock, flags);
         atchan->descs_allocated = i;
         list_splice(&tmp_list, &atchan->free_list);
         atchan->completed_cookie = chan->cookie = 1;
-        spin_unlock_bh(&atchan->lock);
+        spin_unlock_irqrestore(&atchan->lock, flags);
 
         /* channel parameters */
         channel_writel(atchan, CFG, cfg);