diff options
Diffstat (limited to 'drivers/dma/shdma.c')
| -rw-r--r-- | drivers/dma/shdma.c | 132 |
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); |