[PATCH v4 10/11] staging: fsl-mc: Added DPRC interrupt handler

From: J. German Rivera
Date: Fri Dec 11 2015 - 13:28:43 EST


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@xxxxxxxxxxxxx>
---
CHANGE HISTORY

Changes in v4: none

Changes in v3: none

Changes in v2: none

drivers/staging/fsl-mc/bus/dprc-driver.c | 247 +++++++++++++++++++++++++++++++
1 file changed, 247 insertions(+)

diff --git a/drivers/staging/fsl-mc/bus/dprc-driver.c b/drivers/staging/fsl-mc/bus/dprc-driver.c
index 42b2494..52c6fce 100644
--- 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 {
@@ -386,6 +387,230 @@ 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
*
* @mc_dev: Pointer to fsl-mc device representing a DPRC
@@ -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);
--
2.3.3

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