linux-kernel - [PATCH v3 6/7] firmware: coreboot: Only populate devices in coreboot_table

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Date:   Thu,  9 Aug 2018 10:17:21 -0700
From:   Stephen Boyd <swboyd@...omium.org>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     linux-kernel@...r.kernel.org,
        Wei-Ning Huang <wnhuang@...omium.org>,
        Julius Werner <jwerner@...omium.org>,
        Brian Norris <briannorris@...omium.org>,
        Samuel Holland <samuel@...lland.org>
Subject: [PATCH v3 6/7] firmware: coreboot: Only populate devices in coreboot_table_init()

This function checks the header for sanity, registers a bus, and
populates devices for each coreboot table entry. Let's just populate
devices here and pull the other bits up into the caller so that this
function can be repurposed for pure device creation and registration. We
can devm()ify the memory mapping at the same time to keep error paths
simpler.

Cc: Wei-Ning Huang <wnhuang@...omium.org>
Cc: Julius Werner <jwerner@...omium.org>
Cc: Brian Norris <briannorris@...omium.org>
Cc: Samuel Holland <samuel@...lland.org>
Suggested-by: Julius Werner <jwerner@...omium.org>
Signed-off-by: Stephen Boyd <swboyd@...omium.org>
---
 drivers/firmware/google/coreboot_table.c | 66 +++++++++++-------------
 1 file changed, 29 insertions(+), 37 deletions(-)

diff --git a/drivers/firmware/google/coreboot_table.c b/drivers/firmware/google/coreboot_table.c
index f343dbe86448..814913606d22 100644
--- a/drivers/firmware/google/coreboot_table.c
+++ b/drivers/firmware/google/coreboot_table.c
@@ -32,8 +32,6 @@
 #define CB_DEV(d) container_of(d, struct coreboot_device, dev)
 #define CB_DRV(d) container_of(d, struct coreboot_driver, drv)
 
-static struct coreboot_table_header *ptr_header;
-
 static int coreboot_bus_match(struct device *dev, struct device_driver *drv)
 {
 	struct coreboot_device *device = CB_DEV(dev);
@@ -94,35 +92,21 @@ void coreboot_driver_unregister(struct coreboot_driver *driver)
 }
 EXPORT_SYMBOL(coreboot_driver_unregister);
 
-static int coreboot_table_init(struct device *dev, void *ptr)
+static int coreboot_table_populate(struct device *dev, void *ptr)
 {
 	int i, ret;
 	void *ptr_entry;
 	struct coreboot_device *device;
 	struct coreboot_table_entry *entry;
-	struct coreboot_table_header *header;
-
-	ptr_header = ptr;
-	header = ptr;
-
-	if (strncmp(header->signature, "LBIO", sizeof(header->signature))) {
-		pr_warn("coreboot_table: coreboot table missing or corrupt!\n");
-		return -ENODEV;
-	}
-
-	ret = bus_register(&coreboot_bus_type);
-	if (ret)
-		return ret;
+	struct coreboot_table_header *header = ptr;
 
-	ptr_entry = ptr_header + header->header_bytes;
+	ptr_entry = ptr + header->header_bytes;
 	for (i = 0; i < header->table_entries; i++) {
 		entry = ptr_entry;
 
 		device = kzalloc(sizeof(struct device) + entry->size, GFP_KERNEL);
-		if (!device) {
-			ret = -ENOMEM;
-			break;
-		}
+		if (!device)
+			return -ENOMEM;
 
 		dev_set_name(&device->dev, "coreboot%d", i);
 		device->dev.parent = dev;
@@ -133,18 +117,13 @@ static int coreboot_table_init(struct device *dev, void *ptr)
 		ret = device_register(&device->dev);
 		if (ret) {
 			put_device(&device->dev);
-			break;
+			return ret;
 		}
 
 		ptr_entry += entry->size;
 	}
 
-	if (ret) {
-		bus_unregister(&coreboot_bus_type);
-		memunmap(ptr);
-	}
-
-	return ret;
+	return 0;
 }
 
 static int coreboot_table_probe(struct platform_device *pdev)
@@ -152,7 +131,9 @@ static int coreboot_table_probe(struct platform_device *pdev)
 	resource_size_t len;
 	struct coreboot_table_header *header;
 	struct resource *res;
+	struct device *dev = &pdev->dev;
 	void *ptr;
+	int ret;
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	if (!res)
@@ -162,26 +143,37 @@ static int coreboot_table_probe(struct platform_device *pdev)
 	if (!res->start || !len)
 		return -EINVAL;
 
+	/* Map and check just the header first to make sure things are sane */
 	header = memremap(res->start, sizeof(*header), MEMREMAP_WB);
-	if (header == NULL)
+	if (!header)
 		return -ENOMEM;
 
-	ptr = memremap(res->start, header->header_bytes + header->table_bytes,
-		       MEMREMAP_WB);
+	if (strncmp(header->signature, "LBIO", sizeof(header->signature))) {
+		dev_warn(dev, "coreboot table missing or corrupt!\n");
+		return -ENODEV;
+	}
+
+	ptr = devm_memremap(dev, res->start,
+			    header->header_bytes + header->table_bytes,
+			    MEMREMAP_WB);
 	memunmap(header);
 	if (!ptr)
 		return -ENOMEM;
 
-	return coreboot_table_init(&pdev->dev, ptr);
+	ret = bus_register(&coreboot_bus_type);
+	if (ret)
+		return ret;
+
+	ret = coreboot_table_populate(dev, ptr);
+	if (ret)
+		bus_unregister(&coreboot_bus_type);
+
+	return ret;
 }
 
 static int coreboot_table_remove(struct platform_device *pdev)
 {
-	if (ptr_header) {
-		bus_unregister(&coreboot_bus_type);
-		memunmap(ptr_header);
-		ptr_header = NULL;
-	}
+	bus_unregister(&coreboot_bus_type);
 
 	return 0;
 }
-- 
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