1 files changed, 194 insertions, 163 deletions

diff --git a/drivers/bus/fsl-mc/fsl-mc-bus.c b/drivers/bus/fsl-mc/fsl-mc-bus.c
index 09c8ab5e0959..25845c04e562 100644
--- a/drivers/bus/fsl-mc/fsl-mc-bus.c
+++ b/drivers/bus/fsl-mc/fsl-mc-bus.c
@@ -14,13 +14,14 @@
 #include <linux/of_device.h>
 #include <linux/of_address.h>
 #include <linux/ioport.h>
+#include <linux/platform_device.h>
 #include <linux/slab.h>
 #include <linux/limits.h>
 #include <linux/bitops.h>
-#include <linux/msi.h>
 #include <linux/dma-mapping.h>
 #include <linux/acpi.h>
 #include <linux/iommu.h>
+#include <linux/dma-map-ops.h>
 
 #include "fsl-mc-private.h"
 
@@ -63,11 +64,14 @@ struct fsl_mc_addr_translation_range {
 
 #define FSL_MC_GCR1	0x0
 #define GCR1_P1_STOP	BIT(31)
+#define GCR1_P2_STOP	BIT(30)
 
 #define FSL_MC_FAPR	0x28
 #define MC_FAPR_PL	BIT(18)
 #define MC_FAPR_BMT	BIT(17)
 
+static phys_addr_t mc_portal_base_phys_addr;
+
 /**
  * fsl_mc_bus_match - device to driver matching callback
  * @dev: the fsl-mc device to match against
@@ -76,11 +80,11 @@ struct fsl_mc_addr_translation_range {
  *
  * Returns 1 on success, 0 otherwise.
  */
-static int fsl_mc_bus_match(struct device *dev, struct device_driver *drv)
+static int fsl_mc_bus_match(struct device *dev, const struct device_driver *drv)
 {
 	const struct fsl_mc_device_id *id;
 	struct fsl_mc_device *mc_dev = to_fsl_mc_device(dev);
-	struct fsl_mc_driver *mc_drv = to_fsl_mc_driver(drv);
+	const struct fsl_mc_driver *mc_drv = to_fsl_mc_driver(drv);
 	bool found = false;
 
 	/* When driver_override is set, only bind to the matching driver */
@@ -121,9 +125,9 @@ out:
 /*
  * fsl_mc_bus_uevent - callback invoked when a device is added
  */
-static int fsl_mc_bus_uevent(struct device *dev, struct kobj_uevent_env *env)
+static int fsl_mc_bus_uevent(const struct device *dev, struct kobj_uevent_env *env)
 {
-	struct fsl_mc_device *mc_dev = to_fsl_mc_device(dev);
+	const struct fsl_mc_device *mc_dev = to_fsl_mc_device(dev);
 
 	if (add_uevent_var(env, "MODALIAS=fsl-mc:v%08Xd%s",
 			   mc_dev->obj_desc.vendor,
@@ -135,17 +139,36 @@ static int fsl_mc_bus_uevent(struct device *dev, struct kobj_uevent_env *env)
 
 static int fsl_mc_dma_configure(struct device *dev)
 {
+	const struct device_driver *drv = READ_ONCE(dev->driver);
 	struct device *dma_dev = dev;
 	struct fsl_mc_device *mc_dev = to_fsl_mc_device(dev);
 	u32 input_id = mc_dev->icid;
+	int ret;
 
 	while (dev_is_fsl_mc(dma_dev))
 		dma_dev = dma_dev->parent;
 
 	if (dev_of_node(dma_dev))
-		return of_dma_configure_id(dev, dma_dev->of_node, 0, &input_id);
+		ret = of_dma_configure_id(dev, dma_dev->of_node, 0, &input_id);
+	else
+		ret = acpi_dma_configure_id(dev, DEV_DMA_COHERENT, &input_id);
+
+	/* @drv may not be valid when we're called from the IOMMU layer */
+	if (!ret && drv && !to_fsl_mc_driver(drv)->driver_managed_dma) {
+		ret = iommu_device_use_default_domain(dev);
+		if (ret)
+			arch_teardown_dma_ops(dev);
+	}
+
+	return ret;
+}
+
+static void fsl_mc_dma_cleanup(struct device *dev)
+{
+	struct fsl_mc_driver *mc_drv = to_fsl_mc_driver(dev->driver);
 
-	return acpi_dma_configure_id(dev, DEV_DMA_COHERENT, &input_id);
+	if (!mc_drv->driver_managed_dma)
+		iommu_device_unuse_default_domain(dev);
 }
 
 static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
@@ -153,8 +176,8 @@ static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
 {
 	struct fsl_mc_device *mc_dev = to_fsl_mc_device(dev);
 
-	return sprintf(buf, "fsl-mc:v%08Xd%s\n", mc_dev->obj_desc.vendor,
-		       mc_dev->obj_desc.type);
+	return sysfs_emit(buf, "fsl-mc:v%08Xd%s\n", mc_dev->obj_desc.vendor,
+			mc_dev->obj_desc.type);
 }
 static DEVICE_ATTR_RO(modalias);
 
@@ -163,31 +186,14 @@ static ssize_t driver_override_store(struct device *dev,
 				     const char *buf, size_t count)
 {
 	struct fsl_mc_device *mc_dev = to_fsl_mc_device(dev);
-	char *driver_override, *old = mc_dev->driver_override;
-	char *cp;
+	int ret;
 
 	if (WARN_ON(dev->bus != &fsl_mc_bus_type))
 		return -EINVAL;
 
-	if (count >= (PAGE_SIZE - 1))
-		return -EINVAL;
-
-	driver_override = kstrndup(buf, count, GFP_KERNEL);
-	if (!driver_override)
-		return -ENOMEM;
-
-	cp = strchr(driver_override, '\n');
-	if (cp)
-		*cp = '\0';
-
-	if (strlen(driver_override)) {
-		mc_dev->driver_override = driver_override;
-	} else {
-		kfree(driver_override);
-		mc_dev->driver_override = NULL;
-	}
-
-	kfree(old);
+	ret = driver_set_override(dev, &mc_dev->driver_override, buf, count);
+	if (ret)
+		return ret;
 
 	return count;
 }
@@ -197,7 +203,7 @@ static ssize_t driver_override_show(struct device *dev,
 {
 	struct fsl_mc_device *mc_dev = to_fsl_mc_device(dev);
 
-	return snprintf(buf, PAGE_SIZE, "%s\n", mc_dev->driver_override);
+	return sysfs_emit(buf, "%s\n", mc_dev->driver_override);
 }
 static DEVICE_ATTR_RW(driver_override);
 
@@ -220,14 +226,14 @@ static int scan_fsl_mc_bus(struct device *dev, void *data)
 	root_mc_dev = to_fsl_mc_device(dev);
 	root_mc_bus = to_fsl_mc_bus(root_mc_dev);
 	mutex_lock(&root_mc_bus->scan_mutex);
-	dprc_scan_objects(root_mc_dev, NULL);
+	dprc_scan_objects(root_mc_dev, false);
 	mutex_unlock(&root_mc_bus->scan_mutex);
 
 exit:
 	return 0;
 }
 
-static ssize_t rescan_store(struct bus_type *bus,
+static ssize_t rescan_store(const struct bus_type *bus,
 			    const char *buf, size_t count)
 {
 	unsigned long val;
@@ -280,7 +286,7 @@ exit:
 	return 0;
 }
 
-static ssize_t autorescan_store(struct bus_type *bus,
+static ssize_t autorescan_store(const struct bus_type *bus,
 				const char *buf, size_t count)
 {
 	bus_for_each_dev(bus, NULL, (void *)buf, fsl_mc_bus_set_autorescan);
@@ -288,7 +294,7 @@ static ssize_t autorescan_store(struct bus_type *bus,
 	return count;
 }
 
-static ssize_t autorescan_show(struct bus_type *bus, char *buf)
+static ssize_t autorescan_show(const struct bus_type *bus, char *buf)
 {
 	bus_for_each_dev(bus, NULL, (void *)buf, fsl_mc_bus_get_autorescan);
 	return strlen(buf);
@@ -304,100 +310,101 @@ static struct attribute *fsl_mc_bus_attrs[] = {
 
 ATTRIBUTE_GROUPS(fsl_mc_bus);
 
-struct bus_type fsl_mc_bus_type = {
+const struct bus_type fsl_mc_bus_type = {
 	.name = "fsl-mc",
 	.match = fsl_mc_bus_match,
 	.uevent = fsl_mc_bus_uevent,
 	.dma_configure  = fsl_mc_dma_configure,
+	.dma_cleanup = fsl_mc_dma_cleanup,
 	.dev_groups = fsl_mc_dev_groups,
 	.bus_groups = fsl_mc_bus_groups,
 };
 EXPORT_SYMBOL_GPL(fsl_mc_bus_type);
 
-struct device_type fsl_mc_bus_dprc_type = {
+const struct device_type fsl_mc_bus_dprc_type = {
 	.name = "fsl_mc_bus_dprc"
 };
 EXPORT_SYMBOL_GPL(fsl_mc_bus_dprc_type);
 
-struct device_type fsl_mc_bus_dpni_type = {
+const struct device_type fsl_mc_bus_dpni_type = {
 	.name = "fsl_mc_bus_dpni"
 };
 EXPORT_SYMBOL_GPL(fsl_mc_bus_dpni_type);
 
-struct device_type fsl_mc_bus_dpio_type = {
+const struct device_type fsl_mc_bus_dpio_type = {
 	.name = "fsl_mc_bus_dpio"
 };
 EXPORT_SYMBOL_GPL(fsl_mc_bus_dpio_type);
 
-struct device_type fsl_mc_bus_dpsw_type = {
+const struct device_type fsl_mc_bus_dpsw_type = {
 	.name = "fsl_mc_bus_dpsw"
 };
 EXPORT_SYMBOL_GPL(fsl_mc_bus_dpsw_type);
 
-struct device_type fsl_mc_bus_dpbp_type = {
+const struct device_type fsl_mc_bus_dpbp_type = {
 	.name = "fsl_mc_bus_dpbp"
 };
 EXPORT_SYMBOL_GPL(fsl_mc_bus_dpbp_type);
 
-struct device_type fsl_mc_bus_dpcon_type = {
+const struct device_type fsl_mc_bus_dpcon_type = {
 	.name = "fsl_mc_bus_dpcon"
 };
 EXPORT_SYMBOL_GPL(fsl_mc_bus_dpcon_type);
 
-struct device_type fsl_mc_bus_dpmcp_type = {
+const struct device_type fsl_mc_bus_dpmcp_type = {
 	.name = "fsl_mc_bus_dpmcp"
 };
 EXPORT_SYMBOL_GPL(fsl_mc_bus_dpmcp_type);
 
-struct device_type fsl_mc_bus_dpmac_type = {
+const struct device_type fsl_mc_bus_dpmac_type = {
 	.name = "fsl_mc_bus_dpmac"
 };
 EXPORT_SYMBOL_GPL(fsl_mc_bus_dpmac_type);
 
-struct device_type fsl_mc_bus_dprtc_type = {
+const struct device_type fsl_mc_bus_dprtc_type = {
 	.name = "fsl_mc_bus_dprtc"
 };
 EXPORT_SYMBOL_GPL(fsl_mc_bus_dprtc_type);
 
-struct device_type fsl_mc_bus_dpseci_type = {
+const struct device_type fsl_mc_bus_dpseci_type = {
 	.name = "fsl_mc_bus_dpseci"
 };
 EXPORT_SYMBOL_GPL(fsl_mc_bus_dpseci_type);
 
-struct device_type fsl_mc_bus_dpdmux_type = {
+const struct device_type fsl_mc_bus_dpdmux_type = {
 	.name = "fsl_mc_bus_dpdmux"
 };
 EXPORT_SYMBOL_GPL(fsl_mc_bus_dpdmux_type);
 
-struct device_type fsl_mc_bus_dpdcei_type = {
+const struct device_type fsl_mc_bus_dpdcei_type = {
 	.name = "fsl_mc_bus_dpdcei"
 };
 EXPORT_SYMBOL_GPL(fsl_mc_bus_dpdcei_type);
 
-struct device_type fsl_mc_bus_dpaiop_type = {
+const struct device_type fsl_mc_bus_dpaiop_type = {
 	.name = "fsl_mc_bus_dpaiop"
 };
 EXPORT_SYMBOL_GPL(fsl_mc_bus_dpaiop_type);
 
-struct device_type fsl_mc_bus_dpci_type = {
+const struct device_type fsl_mc_bus_dpci_type = {
 	.name = "fsl_mc_bus_dpci"
 };
 EXPORT_SYMBOL_GPL(fsl_mc_bus_dpci_type);
 
-struct device_type fsl_mc_bus_dpdmai_type = {
+const struct device_type fsl_mc_bus_dpdmai_type = {
 	.name = "fsl_mc_bus_dpdmai"
 };
 EXPORT_SYMBOL_GPL(fsl_mc_bus_dpdmai_type);
 
-struct device_type fsl_mc_bus_dpdbg_type = {
+const struct device_type fsl_mc_bus_dpdbg_type = {
 	.name = "fsl_mc_bus_dpdbg"
 };
 EXPORT_SYMBOL_GPL(fsl_mc_bus_dpdbg_type);
 
-static struct device_type *fsl_mc_get_device_type(const char *type)
+static const struct device_type *fsl_mc_get_device_type(const char *type)
 {
 	static const struct {
-		struct device_type *dev_type;
+		const struct device_type *dev_type;
 		const char *type;
 	} dev_types[] = {
 		{ &fsl_mc_bus_dprc_type, "dprc" },
@@ -449,13 +456,8 @@ static int fsl_mc_driver_remove(struct device *dev)
 {
 	struct fsl_mc_driver *mc_drv = to_fsl_mc_driver(dev->driver);
 	struct fsl_mc_device *mc_dev = to_fsl_mc_device(dev);
-	int error;
 
-	error = mc_drv->remove(mc_dev);
-	if (error < 0) {
-		dev_err(dev, "%s failed: %d\n", __func__, error);
-		return error;
-	}
+	mc_drv->remove(mc_dev);
 
 	return 0;
 }
@@ -703,14 +705,30 @@ static int fsl_mc_device_get_mmio_regions(struct fsl_mc_device *mc_dev,
 		 * If base address is in the region_desc use it otherwise
 		 * revert to old mechanism
 		 */
-		if (region_desc.base_address)
+		if (region_desc.base_address) {
 			regions[i].start = region_desc.base_address +
 						region_desc.base_offset;
-		else
+		} else {
 			error = translate_mc_addr(mc_dev, mc_region_type,
 					  region_desc.base_offset,
 					  &regions[i].start);
 
+			/*
+			 * Some versions of the MC firmware wrongly report
+			 * 0 for register base address of the DPMCP associated
+			 * with child DPRC objects thus rendering them unusable.
+			 * This is particularly troublesome in ACPI boot
+			 * scenarios where the legacy way of extracting this
+			 * base address from the device tree does not apply.
+			 * Given that DPMCPs share the same base address,
+			 * workaround this by using the base address extracted
+			 * from the root DPRC container.
+			 */
+			if (is_fsl_mc_bus_dprc(mc_dev) &&
+			    regions[i].start == region_desc.base_offset)
+				regions[i].start += mc_portal_base_phys_addr;
+		}
+
 		if (error < 0) {
 			dev_err(parent_dev,
 				"Invalid MC offset: %#x (for %s.%d\'s region %d)\n",
@@ -888,13 +906,17 @@ int fsl_mc_device_add(struct fsl_mc_obj_desc *obj_desc,
 
 error_cleanup_dev:
 	kfree(mc_dev->regions);
-	kfree(mc_bus);
-	kfree(mc_dev);
+	if (mc_bus)
+		kfree(mc_bus);
+	else
+		kfree(mc_dev);
 
 	return error;
 }
 EXPORT_SYMBOL_GPL(fsl_mc_device_add);
 
+static struct notifier_block fsl_mc_nb;
+
 /**
  * fsl_mc_device_remove - Remove an fsl-mc device from being visible to
  * Linux
@@ -914,17 +936,20 @@ void fsl_mc_device_remove(struct fsl_mc_device *mc_dev)
 }
 EXPORT_SYMBOL_GPL(fsl_mc_device_remove);
 
-struct fsl_mc_device *fsl_mc_get_endpoint(struct fsl_mc_device *mc_dev)
+struct fsl_mc_device *fsl_mc_get_endpoint(struct fsl_mc_device *mc_dev,
+					  u16 if_id)
 {
 	struct fsl_mc_device *mc_bus_dev, *endpoint;
 	struct fsl_mc_obj_desc endpoint_desc = {{ 0 }};
 	struct dprc_endpoint endpoint1 = {{ 0 }};
 	struct dprc_endpoint endpoint2 = {{ 0 }};
+	struct fsl_mc_bus *mc_bus;
 	int state, err;
 
 	mc_bus_dev = to_fsl_mc_device(mc_dev->dev.parent);
 	strcpy(endpoint1.type, mc_dev->obj_desc.type);
 	endpoint1.id = mc_dev->obj_desc.id;
+	endpoint1.if_id = if_id;
 
 	err = dprc_get_connection(mc_bus_dev->mc_io, 0,
 				  mc_bus_dev->mc_handle,
@@ -942,89 +967,48 @@ struct fsl_mc_device *fsl_mc_get_endpoint(struct fsl_mc_device *mc_dev)
 	strcpy(endpoint_desc.type, endpoint2.type);
 	endpoint_desc.id = endpoint2.id;
 	endpoint = fsl_mc_device_lookup(&endpoint_desc, mc_bus_dev);
+	if (endpoint)
+		return endpoint;
 
 	/*
 	 * We know that the device has an endpoint because we verified by
 	 * interrogating the firmware. This is the case when the device was not
 	 * yet discovered by the fsl-mc bus, thus the lookup returned NULL.
-	 * Differentiate this case by returning EPROBE_DEFER.
+	 * Force a rescan of the devices in this container and retry the lookup.
+	 */
+	mc_bus = to_fsl_mc_bus(mc_bus_dev);
+	if (mutex_trylock(&mc_bus->scan_mutex)) {
+		err = dprc_scan_objects(mc_bus_dev, true);
+		mutex_unlock(&mc_bus->scan_mutex);
+	}
+	if (err < 0)
+		return ERR_PTR(err);
+
+	endpoint = fsl_mc_device_lookup(&endpoint_desc, mc_bus_dev);
+	/*
+	 * This means that the endpoint might reside in a different isolation
+	 * context (DPRC/container). Not much to do, so return a permssion
+	 * error.
 	 */
 	if (!endpoint)
-		return ERR_PTR(-EPROBE_DEFER);
+		return ERR_PTR(-EPERM);
 
 	return endpoint;
 }
 EXPORT_SYMBOL_GPL(fsl_mc_get_endpoint);
 
-static int parse_mc_ranges(struct device *dev,
-			   int *paddr_cells,
-			   int *mc_addr_cells,
-			   int *mc_size_cells,
-			   const __be32 **ranges_start)
-{
-	const __be32 *prop;
-	int range_tuple_cell_count;
-	int ranges_len;
-	int tuple_len;
-	struct device_node *mc_node = dev->of_node;
-
-	*ranges_start = of_get_property(mc_node, "ranges", &ranges_len);
-	if (!(*ranges_start) || !ranges_len) {
-		dev_warn(dev,
-			 "missing or empty ranges property for device tree node '%pOFn'\n",
-			 mc_node);
-		return 0;
-	}
-
-	*paddr_cells = of_n_addr_cells(mc_node);
-
-	prop = of_get_property(mc_node, "#address-cells", NULL);
-	if (prop)
-		*mc_addr_cells = be32_to_cpup(prop);
-	else
-		*mc_addr_cells = *paddr_cells;
-
-	prop = of_get_property(mc_node, "#size-cells", NULL);
-	if (prop)
-		*mc_size_cells = be32_to_cpup(prop);
-	else
-		*mc_size_cells = of_n_size_cells(mc_node);
-
-	range_tuple_cell_count = *paddr_cells + *mc_addr_cells +
-				 *mc_size_cells;
-
-	tuple_len = range_tuple_cell_count * sizeof(__be32);
-	if (ranges_len % tuple_len != 0) {
-		dev_err(dev, "malformed ranges property '%pOFn'\n", mc_node);
-		return -EINVAL;
-	}
-
-	return ranges_len / tuple_len;
-}
-
 static int get_mc_addr_translation_ranges(struct device *dev,
 					  struct fsl_mc_addr_translation_range
 						**ranges,
 					  u8 *num_ranges)
 {
-	int ret;
-	int paddr_cells;
-	int mc_addr_cells;
-	int mc_size_cells;
-	int i;
-	const __be32 *ranges_start;
-	const __be32 *cell;
-
-	ret = parse_mc_ranges(dev,
-			      &paddr_cells,
-			      &mc_addr_cells,
-			      &mc_size_cells,
-			      &ranges_start);
-	if (ret < 0)
-		return ret;
+	struct fsl_mc_addr_translation_range *r;
+	struct of_range_parser parser;
+	struct of_range range;
 
-	*num_ranges = ret;
-	if (!ret) {
+	of_range_parser_init(&parser, dev->of_node);
+	*num_ranges = of_range_count(&parser);
+	if (!*num_ranges) {
 		/*
 		 * Missing or empty ranges property ("ranges;") for the
 		 * 'fsl,qoriq-mc' node. In this case, identity mapping
@@ -1040,20 +1024,13 @@ static int get_mc_addr_translation_ranges(struct device *dev,
 	if (!(*ranges))
 		return -ENOMEM;
 
-	cell = ranges_start;
-	for (i = 0; i < *num_ranges; ++i) {
-		struct fsl_mc_addr_translation_range *range = &(*ranges)[i];
-
-		range->mc_region_type = of_read_number(cell, 1);
-		range->start_mc_offset = of_read_number(cell + 1,
-							mc_addr_cells - 1);
-		cell += mc_addr_cells;
-		range->start_phys_addr = of_read_number(cell, paddr_cells);
-		cell += paddr_cells;
-		range->end_mc_offset = range->start_mc_offset +
-				     of_read_number(cell, mc_size_cells);
-
-		cell += mc_size_cells;
+	r = *ranges;
+	for_each_of_range(&parser, &range) {
+		r->mc_region_type = range.flags;
+		r->start_mc_offset = range.bus_addr;
+		r->end_mc_offset = range.bus_addr + range.size;
+		r->start_phys_addr = range.cpu_addr;
+		r++;
 	}
 
 	return 0;
@@ -1089,17 +1066,6 @@ static int fsl_mc_bus_probe(struct platform_device *pdev)
 	}
 
 	if (mc->fsl_mc_regs) {
-		/*
-		 * Some bootloaders pause the MC firmware before booting the
-		 * kernel so that MC will not cause faults as soon as the
-		 * SMMU probes due to the fact that there's no configuration
-		 * in place for MC.
-		 * At this point MC should have all its SMMU setup done so make
-		 * sure it is resumed.
-		 */
-		writel(readl(mc->fsl_mc_regs + FSL_MC_GCR1) & (~GCR1_P1_STOP),
-		       mc->fsl_mc_regs + FSL_MC_GCR1);
-
 		if (IS_ENABLED(CONFIG_ACPI) && !dev_of_node(&pdev->dev)) {
 			mc_stream_id = readl(mc->fsl_mc_regs + FSL_MC_FAPR);
 			/*
@@ -1113,19 +1079,38 @@ static int fsl_mc_bus_probe(struct platform_device *pdev)
 			error = acpi_dma_configure_id(&pdev->dev,
 						      DEV_DMA_COHERENT,
 						      &mc_stream_id);
+			if (error == -EPROBE_DEFER)
+				return error;
 			if (error)
 				dev_warn(&pdev->dev,
 					 "failed to configure dma: %d.\n",
 					 error);
 		}
+
+		/*
+		 * Some bootloaders pause the MC firmware before booting the
+		 * kernel so that MC will not cause faults as soon as the
+		 * SMMU probes due to the fact that there's no configuration
+		 * in place for MC.
+		 * At this point MC should have all its SMMU setup done so make
+		 * sure it is resumed.
+		 */
+		writel(readl(mc->fsl_mc_regs + FSL_MC_GCR1) &
+			     (~(GCR1_P1_STOP | GCR1_P2_STOP)),
+		       mc->fsl_mc_regs + FSL_MC_GCR1);
 	}
 
 	/*
 	 * Get physical address of MC portal for the root DPRC:
 	 */
 	plat_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!plat_res)
+		return -EINVAL;
+
 	mc_portal_phys_addr = plat_res->start;
 	mc_portal_size = resource_size(plat_res);
+	mc_portal_base_phys_addr = mc_portal_phys_addr & ~0x3ffffff;
+
 	error = fsl_create_mc_io(&pdev->dev, mc_portal_phys_addr,
 				 mc_portal_size, NULL,
 				 FSL_MC_IO_ATOMIC_CONTEXT_PORTAL, &mc_io);
@@ -1187,19 +1172,26 @@ error_cleanup_mc_io:
  * fsl_mc_bus_remove - callback invoked when the root MC bus is being
  * removed
  */
-static int fsl_mc_bus_remove(struct platform_device *pdev)
+static void fsl_mc_bus_remove(struct platform_device *pdev)
 {
 	struct fsl_mc *mc = platform_get_drvdata(pdev);
+	struct fsl_mc_io *mc_io;
 
-	if (!fsl_mc_is_root_dprc(&mc->root_mc_bus_dev->dev))
-		return -EINVAL;
-
+	mc_io = mc->root_mc_bus_dev->mc_io;
 	fsl_mc_device_remove(mc->root_mc_bus_dev);
+	fsl_destroy_mc_io(mc_io);
 
-	fsl_destroy_mc_io(mc->root_mc_bus_dev->mc_io);
-	mc->root_mc_bus_dev->mc_io = NULL;
+	bus_unregister_notifier(&fsl_mc_bus_type, &fsl_mc_nb);
 
-	return 0;
+	if (mc->fsl_mc_regs) {
+		/*
+		 * Pause the MC firmware so that it doesn't crash in certain
+		 * scenarios, such as kexec.
+		 */
+		writel(readl(mc->fsl_mc_regs + FSL_MC_GCR1) |
+		       (GCR1_P1_STOP | GCR1_P2_STOP),
+		       mc->fsl_mc_regs + FSL_MC_GCR1);
+	}
 }
 
 static const struct of_device_id fsl_mc_bus_match_table[] = {
@@ -1224,6 +1216,45 @@ static struct platform_driver fsl_mc_bus_driver = {
 		   },
 	.probe = fsl_mc_bus_probe,
 	.remove = fsl_mc_bus_remove,
+	.shutdown = fsl_mc_bus_remove,
+};
+
+static int fsl_mc_bus_notifier(struct notifier_block *nb,
+			       unsigned long action, void *data)
+{
+	struct device *dev = data;
+	struct resource *res;
+	void __iomem *fsl_mc_regs;
+
+	if (action != BUS_NOTIFY_ADD_DEVICE)
+		return 0;
+
+	if (!of_match_device(fsl_mc_bus_match_table, dev) &&
+	    !acpi_match_device(fsl_mc_bus_acpi_match_table, dev))
+		return 0;
+
+	res = platform_get_resource(to_platform_device(dev), IORESOURCE_MEM, 1);
+	if (!res)
+		return 0;
+
+	fsl_mc_regs = ioremap(res->start, resource_size(res));
+	if (!fsl_mc_regs)
+		return 0;
+
+	/*
+	 * Make sure that the MC firmware is paused before the IOMMU setup for
+	 * it is done or otherwise the firmware will crash right after the SMMU
+	 * gets probed and enabled.
+	 */
+	writel(readl(fsl_mc_regs + FSL_MC_GCR1) | (GCR1_P1_STOP | GCR1_P2_STOP),
+	       fsl_mc_regs + FSL_MC_GCR1);
+	iounmap(fsl_mc_regs);
+
+	return 0;
+}
+
+static struct notifier_block fsl_mc_nb = {
+	.notifier_call = fsl_mc_bus_notifier,
 };
 
 static int __init fsl_mc_bus_driver_init(void)
@@ -1250,7 +1281,7 @@ static int __init fsl_mc_bus_driver_init(void)
 	if (error < 0)
 		goto error_cleanup_dprc_driver;
 
-	return 0;
+	return bus_register_notifier(&platform_bus_type, &fsl_mc_nb);
 
 error_cleanup_dprc_driver:
 	dprc_driver_exit();