linux-kernel - [PATCH 1/2] staging: fsl-mc: Allocate IRQ's before scanning DPRC objects

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Date:   Wed, 6 Dec 2017 21:48:06 +0530
From:   Nipun Gupta <nipun.gupta@....com>
To:     <laurentiu.tudor@....com>, <stuyoder@...il.com>,
        <bharat.bhushan@....com>, <gregkh@...uxfoundation.org>,
        <cakturk@...il.com>, <bretth256@...il.com>, <arnd@...db.de>
CC:     <linux-kernel@...r.kernel.org>, <devel@...verdev.osuosl.org>,
        Nipun Gupta <nipun.gupta@....com>
Subject: [PATCH 1/2] staging: fsl-mc: Allocate IRQ's before scanning DPRC objects

When DPRC probing is deferred (such as where IOMMU is not probed
before the fsl-mc bus), all the devices in the DPRC containers gets
initialized one after another. As IRQ's were allocated only once the
DPRC scanning is completed, the devices like DPIO which uses these
IRQ's at initalization fails. This patch allocates the IRQ resources
before scanning all the objects in the DPRC container.

Signed-off-by: Nipun Gupta <nipun.gupta@....com>
---
 drivers/staging/fsl-mc/bus/dprc-driver.c | 49 ++++++++++++++++++--------------
 1 file changed, 27 insertions(+), 22 deletions(-)

diff --git a/drivers/staging/fsl-mc/bus/dprc-driver.c b/drivers/staging/fsl-mc/bus/dprc-driver.c
index 06df528..7265431 100644
--- a/drivers/staging/fsl-mc/bus/dprc-driver.c
+++ b/drivers/staging/fsl-mc/bus/dprc-driver.c
@@ -206,7 +206,8 @@ static void dprc_add_new_devices(struct fsl_mc_device *mc_bus_dev,
  * dprc_scan_objects - Discover objects in a DPRC
  *
  * @mc_bus_dev: pointer to the fsl-mc device that represents a DPRC object
- * @total_irq_count: total number of IRQs needed by objects in the DPRC.
+ * @total_irq_count: If argument is provided the function populates the
+ * total number of IRQs created by objects in the DPRC.
  *
  * Detects objects added and removed from a DPRC and synchronizes the
  * state of the Linux bus driver, MC by adding and removing
@@ -228,6 +229,7 @@ static int dprc_scan_objects(struct fsl_mc_device *mc_bus_dev,
 	int error;
 	unsigned int irq_count = mc_bus_dev->obj_desc.irq_count;
 	struct fsl_mc_obj_desc *child_obj_desc_array = NULL;
+	struct fsl_mc_bus *mc_bus = to_fsl_mc_bus(mc_bus_dev);
 
 	error = dprc_get_obj_count(mc_bus_dev->mc_io,
 				   0,
@@ -297,7 +299,26 @@ static int dprc_scan_objects(struct fsl_mc_device *mc_bus_dev,
 		}
 	}
 
-	*total_irq_count = irq_count;
+	/*
+	 * Allocate IRQ's before scanning objects in DPRC as some devices like
+	 * DPIO needs them on being probed.
+	 */
+	if (dev_get_msi_domain(&mc_bus_dev->dev) && !mc_bus->irq_resources) {
+		if (irq_count > FSL_MC_IRQ_POOL_MAX_TOTAL_IRQS) {
+			dev_warn(&mc_bus_dev->dev,
+				 "IRQs needed (%u) exceed IRQs preallocated (%u)\n",
+				 irq_count, FSL_MC_IRQ_POOL_MAX_TOTAL_IRQS);
+		}
+
+		error = fsl_mc_populate_irq_pool(mc_bus,
+				FSL_MC_IRQ_POOL_MAX_TOTAL_IRQS);
+		if (error < 0)
+			return error;
+	}
+
+	if (total_irq_count)
+		*total_irq_count = irq_count;
+
 	dprc_remove_devices(mc_bus_dev, child_obj_desc_array,
 			    num_child_objects);
 
@@ -322,7 +343,6 @@ static int dprc_scan_objects(struct fsl_mc_device *mc_bus_dev,
 static int dprc_scan_container(struct fsl_mc_device *mc_bus_dev)
 {
 	int error;
-	unsigned int irq_count;
 	struct fsl_mc_bus *mc_bus = to_fsl_mc_bus(mc_bus_dev);
 
 	fsl_mc_init_all_resource_pools(mc_bus_dev);
@@ -331,29 +351,14 @@ static int dprc_scan_container(struct fsl_mc_device *mc_bus_dev)
 	 * Discover objects in the DPRC:
 	 */
 	mutex_lock(&mc_bus->scan_mutex);
-	error = dprc_scan_objects(mc_bus_dev, &irq_count);
+	error = dprc_scan_objects(mc_bus_dev, NULL);
 	mutex_unlock(&mc_bus->scan_mutex);
-	if (error < 0)
-		goto error;
-
-	if (dev_get_msi_domain(&mc_bus_dev->dev) && !mc_bus->irq_resources) {
-		if (irq_count > FSL_MC_IRQ_POOL_MAX_TOTAL_IRQS) {
-			dev_warn(&mc_bus_dev->dev,
-				 "IRQs needed (%u) exceed IRQs preallocated (%u)\n",
-				 irq_count, FSL_MC_IRQ_POOL_MAX_TOTAL_IRQS);
-		}
-
-		error = fsl_mc_populate_irq_pool(
-				mc_bus,
-				FSL_MC_IRQ_POOL_MAX_TOTAL_IRQS);
-		if (error < 0)
-			goto error;
+	if (error < 0) {
+		fsl_mc_cleanup_all_resource_pools(mc_bus_dev);
+		return error;
 	}
 
 	return 0;
-error:
-	fsl_mc_cleanup_all_resource_pools(mc_bus_dev);
-	return error;
 }
 
 /**
-- 
1.9.1