staging: fsl-mc: Added DPRC interrupt handler

The interrupt handler for DPRC IRQs is added. DPRC IRQs are
generated for hot plug events related to DPAA2 objects in a given
DPRC. These events include, creating/destroying DPAA2 objects in
the DPRC, changing the "plugged" state of DPAA2 objects and moving
objects between DPRCs.

Signed-off-by: J. German Rivera <German.Rivera@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/fsl-mc/bus/dprc-driver.c b/drivers/staging/fsl-mc/bus/dprc-driver.c
index 42b2494046322e37e7407fb6668cd199f399c7d0..52c6fce0fd29e673044e2c75d09f618ded5b2568 100644 (file)
--- a/drivers/staging/fsl-mc/bus/dprc-driver.c
+++ b/drivers/staging/fsl-mc/bus/dprc-driver.c
@@ -14,6 +14,7 @@
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/interrupt.h>
+#include <linux/msi.h>
 #include "dprc-cmd.h"
 
 struct dprc_child_objs {
@@ -385,6 +386,230 @@ error:
 }
 EXPORT_SYMBOL_GPL(dprc_scan_container);
 
+/**
+ * dprc_irq0_handler - Regular ISR for DPRC interrupt 0
+ *
+ * @irq: IRQ number of the interrupt being handled
+ * @arg: Pointer to device structure
+ */
+static irqreturn_t dprc_irq0_handler(int irq_num, void *arg)
+{
+       return IRQ_WAKE_THREAD;
+}
+
+/**
+ * dprc_irq0_handler_thread - Handler thread function for DPRC interrupt 0
+ *
+ * @irq: IRQ number of the interrupt being handled
+ * @arg: Pointer to device structure
+ */
+static irqreturn_t dprc_irq0_handler_thread(int irq_num, void *arg)
+{
+       int error;
+       u32 status;
+       struct device *dev = (struct device *)arg;
+       struct fsl_mc_device *mc_dev = to_fsl_mc_device(dev);
+       struct fsl_mc_bus *mc_bus = to_fsl_mc_bus(mc_dev);
+       struct fsl_mc_io *mc_io = mc_dev->mc_io;
+       struct msi_desc *msi_desc = mc_dev->irqs[0]->msi_desc;
+
+       dev_dbg(dev, "DPRC IRQ %d triggered on CPU %u\n",
+               irq_num, smp_processor_id());
+
+       if (WARN_ON(!(mc_dev->flags & FSL_MC_IS_DPRC)))
+               return IRQ_HANDLED;
+
+       mutex_lock(&mc_bus->scan_mutex);
+       if (WARN_ON(!msi_desc || msi_desc->irq != (u32)irq_num))
+               goto out;
+
+       error = dprc_get_irq_status(mc_io, 0, mc_dev->mc_handle, 0,
+                                   &status);
+       if (error < 0) {
+               dev_err(dev,
+                       "dprc_get_irq_status() failed: %d\n", error);
+               goto out;
+       }
+
+       error = dprc_clear_irq_status(mc_io, 0, mc_dev->mc_handle, 0,
+                                     status);
+       if (error < 0) {
+               dev_err(dev,
+                       "dprc_clear_irq_status() failed: %d\n", error);
+               goto out;
+       }
+
+       if (status & (DPRC_IRQ_EVENT_OBJ_ADDED |
+                     DPRC_IRQ_EVENT_OBJ_REMOVED |
+                     DPRC_IRQ_EVENT_CONTAINER_DESTROYED |
+                     DPRC_IRQ_EVENT_OBJ_DESTROYED |
+                     DPRC_IRQ_EVENT_OBJ_CREATED)) {
+               unsigned int irq_count;
+
+               error = dprc_scan_objects(mc_dev, &irq_count);
+               if (error < 0) {
+                       /*
+                        * If the error is -ENXIO, we ignore it, as it indicates
+                        * that the object scan was aborted, as we detected that
+                        * an object was removed from the DPRC in the MC, while
+                        * we were scanning the DPRC.
+                        */
+                       if (error != -ENXIO) {
+                               dev_err(dev, "dprc_scan_objects() failed: %d\n",
+                                       error);
+                       }
+
+                       goto out;
+               }
+
+               if (irq_count > FSL_MC_IRQ_POOL_MAX_TOTAL_IRQS) {
+                       dev_warn(dev,
+                                "IRQs needed (%u) exceed IRQs preallocated (%u)\n",
+                                irq_count, FSL_MC_IRQ_POOL_MAX_TOTAL_IRQS);
+               }
+       }
+
+out:
+       mutex_unlock(&mc_bus->scan_mutex);
+       return IRQ_HANDLED;
+}
+
+/*
+ * Disable and clear interrupt for a given DPRC object
+ */
+static int disable_dprc_irq(struct fsl_mc_device *mc_dev)
+{
+       int error;
+       struct fsl_mc_io *mc_io = mc_dev->mc_io;
+
+       WARN_ON(mc_dev->obj_desc.irq_count != 1);
+
+       /*
+        * Disable generation of interrupt, while we configure it:
+        */
+       error = dprc_set_irq_enable(mc_io, 0, mc_dev->mc_handle, 0, 0);
+       if (error < 0) {
+               dev_err(&mc_dev->dev,
+                       "Disabling DPRC IRQ failed: dprc_set_irq_enable() failed: %d\n",
+                       error);
+               return error;
+       }
+
+       /*
+        * Disable all interrupt causes for the interrupt:
+        */
+       error = dprc_set_irq_mask(mc_io, 0, mc_dev->mc_handle, 0, 0x0);
+       if (error < 0) {
+               dev_err(&mc_dev->dev,
+                       "Disabling DPRC IRQ failed: dprc_set_irq_mask() failed: %d\n",
+                       error);
+               return error;
+       }
+
+       /*
+        * Clear any leftover interrupts:
+        */
+       error = dprc_clear_irq_status(mc_io, 0, mc_dev->mc_handle, 0, ~0x0U);
+       if (error < 0) {
+               dev_err(&mc_dev->dev,
+                       "Disabling DPRC IRQ failed: dprc_clear_irq_status() failed: %d\n",
+                       error);
+               return error;
+       }
+
+       return 0;
+}
+
+static int register_dprc_irq_handler(struct fsl_mc_device *mc_dev)
+{
+       int error;
+       struct fsl_mc_device_irq *irq = mc_dev->irqs[0];
+
+       WARN_ON(mc_dev->obj_desc.irq_count != 1);
+
+       /*
+        * NOTE: devm_request_threaded_irq() invokes the device-specific
+        * function that programs the MSI physically in the device
+        */
+       error = devm_request_threaded_irq(&mc_dev->dev,
+                                         irq->msi_desc->irq,
+                                         dprc_irq0_handler,
+                                         dprc_irq0_handler_thread,
+                                         IRQF_NO_SUSPEND | IRQF_ONESHOT,
+                                         "FSL MC DPRC irq0",
+                                         &mc_dev->dev);
+       if (error < 0) {
+               dev_err(&mc_dev->dev,
+                       "devm_request_threaded_irq() failed: %d\n",
+                       error);
+               return error;
+       }
+
+       return 0;
+}
+
+static int enable_dprc_irq(struct fsl_mc_device *mc_dev)
+{
+       int error;
+
+       /*
+        * Enable all interrupt causes for the interrupt:
+        */
+       error = dprc_set_irq_mask(mc_dev->mc_io, 0, mc_dev->mc_handle, 0,
+                                 ~0x0u);
+       if (error < 0) {
+               dev_err(&mc_dev->dev,
+                       "Enabling DPRC IRQ failed: dprc_set_irq_mask() failed: %d\n",
+                       error);
+
+               return error;
+       }
+
+       /*
+        * Enable generation of the interrupt:
+        */
+       error = dprc_set_irq_enable(mc_dev->mc_io, 0, mc_dev->mc_handle, 0, 1);
+       if (error < 0) {
+               dev_err(&mc_dev->dev,
+                       "Enabling DPRC IRQ failed: dprc_set_irq_enable() failed: %d\n",
+                       error);
+
+               return error;
+       }
+
+       return 0;
+}
+
+/*
+ * Setup interrupt for a given DPRC device
+ */
+static int dprc_setup_irq(struct fsl_mc_device *mc_dev)
+{
+       int error;
+
+       error = fsl_mc_allocate_irqs(mc_dev);
+       if (error < 0)
+               return error;
+
+       error = disable_dprc_irq(mc_dev);
+       if (error < 0)
+               goto error_free_irqs;
+
+       error = register_dprc_irq_handler(mc_dev);
+       if (error < 0)
+               goto error_free_irqs;
+
+       error = enable_dprc_irq(mc_dev);
+       if (error < 0)
+               goto error_free_irqs;
+
+       return 0;
+
+error_free_irqs:
+       fsl_mc_free_irqs(mc_dev);
+       return error;
+}
+
 /**
  * dprc_probe - callback invoked when a DPRC is being bound to this driver
  *
@@ -476,6 +701,13 @@ static int dprc_probe(struct fsl_mc_device *mc_dev)
        if (error < 0)
                goto error_cleanup_open;
 
+       /*
+        * Configure interrupt for the DPRC object associated with this MC bus:
+        */
+       error = dprc_setup_irq(mc_dev);
+       if (error < 0)
+               goto error_cleanup_open;
+
        dev_info(&mc_dev->dev, "DPRC device bound to driver");
        return 0;
 
@@ -494,6 +726,15 @@ error_cleanup_msi_domain:
        return error;
 }
 
+/*
+ * Tear down interrupt for a given DPRC object
+ */
+static void dprc_teardown_irq(struct fsl_mc_device *mc_dev)
+{
+       (void)disable_dprc_irq(mc_dev);
+       fsl_mc_free_irqs(mc_dev);
+}
+
 /**
  * dprc_remove - callback invoked when a DPRC is being unbound from this driver
  *
@@ -514,6 +755,12 @@ static int dprc_remove(struct fsl_mc_device *mc_dev)
        if (WARN_ON(!mc_dev->mc_io))
                return -EINVAL;
 
+       if (WARN_ON(!mc_bus->irq_resources))
+               return -EINVAL;
+
+       if (dev_get_msi_domain(&mc_dev->dev))
+               dprc_teardown_irq(mc_dev);
+
        device_for_each_child(&mc_dev->dev, NULL, __fsl_mc_device_remove);
        dprc_cleanup_all_resource_pools(mc_dev);
        error = dprc_close(mc_dev->mc_io, 0, mc_dev->mc_handle);