1 files changed, 114 insertions, 18 deletions

diff --git a/drivers/dma/shdma.c b/drivers/dma/shdma.c
index 85ffd5e38c50..a0069c171518 100644
--- a/drivers/dma/shdma.c
+++ b/drivers/dma/shdma.c
@@ -27,7 +27,10 @@
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
 #include <linux/sh_dma.h>
-
+#include <linux/notifier.h>
+#include <linux/kdebug.h>
+#include <linux/spinlock.h>
+#include <linux/rculist.h>
 #include "shdma.h"
 
 /* DMA descriptor control */
@@ -43,6 +46,13 @@ enum sh_dmae_desc_status {
 /* Default MEMCPY transfer size = 2^2 = 4 bytes */
 #define LOG2_DEFAULT_XFER_SIZE  2
 
+/*
+ * Used for write-side mutual exclusion for the global device list,
+ * read-side synchronization by way of RCU.
+ */
+static DEFINE_SPINLOCK(sh_dmae_lock);
+static LIST_HEAD(sh_dmae_devices);
+
 /* A bitmask with bits enough for enum sh_dmae_slave_chan_id */
 static unsigned long sh_dmae_slave_used[BITS_TO_LONGS(SH_DMA_SLAVE_NUMBER)];
 
@@ -817,10 +827,9 @@ static irqreturn_t sh_dmae_interrupt(int irq, void *data)
         return ret;
 }
 
-#if defined(CONFIG_CPU_SH4) || defined(CONFIG_ARCH_SHMOBILE)
-static irqreturn_t sh_dmae_err(int irq, void *data)
+static unsigned int sh_dmae_reset(struct sh_dmae_device *shdev)
 {
-        struct sh_dmae_device *shdev = (struct sh_dmae_device *)data;
+        unsigned int handled = 0;
         int i;
 
         /* halt the dma controller */
@@ -829,25 +838,35 @@ static irqreturn_t sh_dmae_err(int irq, void *data)
         /* We cannot detect, which channel caused the error, have to reset all */
         for (i = 0; i < SH_DMAC_MAX_CHANNELS; i++) {
                 struct sh_dmae_chan *sh_chan = shdev->chan[i];
-                if (sh_chan) {
-                        struct sh_desc *desc;
-                        /* Stop the channel */
-                        dmae_halt(sh_chan);
-                        /* Complete all  */
-                        list_for_each_entry(desc, &sh_chan->ld_queue, node) {
-                                struct dma_async_tx_descriptor *tx = &desc->async_tx;
-                                desc->mark = DESC_IDLE;
-                                if (tx->callback)
-                                        tx->callback(tx->callback_param);
-                        }
-                        list_splice_init(&sh_chan->ld_queue, &sh_chan->ld_free);
+                struct sh_desc *desc;
+
+                if (!sh_chan)
+                        continue;
+
+                /* Stop the channel */
+                dmae_halt(sh_chan);
+
+                /* Complete all  */
+                list_for_each_entry(desc, &sh_chan->ld_queue, node) {
+                        struct dma_async_tx_descriptor *tx = &desc->async_tx;
+                        desc->mark = DESC_IDLE;
+                        if (tx->callback)
+                                tx->callback(tx->callback_param);
                 }
+
+                list_splice_init(&sh_chan->ld_queue, &sh_chan->ld_free);
+                handled++;
         }
+
         sh_dmae_rst(shdev);
 
-        return IRQ_HANDLED;
+        return !!handled;
+}
+
+static irqreturn_t sh_dmae_err(int irq, void *data)
+{
+        return IRQ_RETVAL(sh_dmae_reset(data));
 }
-#endif
 
 static void dmae_do_tasklet(unsigned long data)
 {
@@ -876,6 +895,60 @@ static void dmae_do_tasklet(unsigned long data)
         sh_dmae_chan_ld_cleanup(sh_chan, false);
 }
 
+static bool sh_dmae_nmi_notify(struct sh_dmae_device *shdev)
+{
+        unsigned int handled;
+
+        /* Fast path out if NMIF is not asserted for this controller */
+        if ((dmaor_read(shdev) & DMAOR_NMIF) == 0)
+                return false;
+
+        handled = sh_dmae_reset(shdev);
+        if (handled)
+                return true;
+
+        return false;
+}
+
+static int sh_dmae_nmi_handler(struct notifier_block *self,
+                               unsigned long cmd, void *data)
+{
+        struct sh_dmae_device *shdev;
+        int ret = NOTIFY_DONE;
+        bool triggered;
+
+        /*
+         * Only concern ourselves with NMI events.
+         *
+         * Normally we would check the die chain value, but as this needs
+         * to be architecture independent, check for NMI context instead.
+         */
+        if (!in_nmi())
+                return NOTIFY_DONE;
+
+        rcu_read_lock();
+        list_for_each_entry_rcu(shdev, &sh_dmae_devices, node) {
+                /*
+                 * Only stop if one of the controllers has NMIF asserted,
+                 * we do not want to interfere with regular address error
+                 * handling or NMI events that don't concern the DMACs.
+                 */
+                triggered = sh_dmae_nmi_notify(shdev);
+                if (triggered == true)
+                        ret = NOTIFY_OK;
+        }
+        rcu_read_unlock();
+
+        return ret;
+}
+
+static struct notifier_block sh_dmae_nmi_notifier __read_mostly = {
+        .notifier_call  = sh_dmae_nmi_handler,
+
+        /* Run before NMI debug handler and KGDB */
+        .priority       = 1,
+};
+
 static int __devinit sh_dmae_chan_probe(struct sh_dmae_device *shdev, int id,
                                         int irq, unsigned long flags)
 {
@@ -967,6 +1040,7 @@ static int __init sh_dmae_probe(struct platform_device *pdev)
         struct sh_dmae_pdata *pdata = pdev->dev.platform_data;
         unsigned long irqflags = IRQF_DISABLED,
                 chan_flag[SH_DMAC_MAX_CHANNELS] = {};
+        unsigned long flags;
         int errirq, chan_irq[SH_DMAC_MAX_CHANNELS];
         int err, i, irq_cnt = 0, irqres = 0;
         struct sh_dmae_device *shdev;
@@ -1032,6 +1106,15 @@ static int __init sh_dmae_probe(struct platform_device *pdev)
         pm_runtime_enable(&pdev->dev);
         pm_runtime_get_sync(&pdev->dev);
 
+        spin_lock_irqsave(&sh_dmae_lock, flags);
+        list_add_tail_rcu(&shdev->node, &sh_dmae_devices);
+        spin_unlock_irqrestore(&sh_dmae_lock, flags);
+
+        /* Wire up NMI handling before bringing the controller online */
+        err = register_die_notifier(&sh_dmae_nmi_notifier);
+        if (err)
+                goto notifier_err;
+
         /* reset dma controller */
         err = sh_dmae_rst(shdev);
         if (err)
@@ -1135,6 +1218,12 @@ eirqres:
 eirq_err:
 #endif
 rst_err:
+        unregister_die_notifier(&sh_dmae_nmi_notifier);
+notifier_err:
+        spin_lock_irqsave(&sh_dmae_lock, flags);
+        list_del_rcu(&shdev->node);
+        spin_unlock_irqrestore(&sh_dmae_lock, flags);
+
         pm_runtime_put(&pdev->dev);
         if (dmars)
                 iounmap(shdev->dmars);
@@ -1155,6 +1244,7 @@ static int __exit sh_dmae_remove(struct platform_device *pdev)
 {
         struct sh_dmae_device *shdev = platform_get_drvdata(pdev);
         struct resource *res;
+        unsigned long flags;
         int errirq = platform_get_irq(pdev, 0);
 
         dma_async_device_unregister(&shdev->common);
@@ -1162,6 +1252,12 @@ static int __exit sh_dmae_remove(struct platform_device *pdev)
         if (errirq > 0)
                 free_irq(errirq, shdev);
 
+        unregister_die_notifier(&sh_dmae_nmi_notifier);
+
+        spin_lock_irqsave(&sh_dmae_lock, flags);
+        list_del_rcu(&shdev->node);
+        spin_unlock_irqrestore(&sh_dmae_lock, flags);
+
         /* channel data remove */
         sh_dmae_chan_remove(shdev);