[PATCH] PCI: Refactor pci_ioremap_bar() and pci_ioremap_wc_bar()

["Krzysztof Wilczyński" <kw@linux.com>]

Currently, functions pci_ioremap_bar() and pci_ioremap_wc_bar() share
similar implementation details as both functions were almost identical
in the past, especially when the latter was initially introduced in the
commit c43996f4001d ("PCI: Add pci_ioremap_wc_bar()") as somewhat exact
copy of the function pci_ioremap_bar().

However, function pci_ioremap_bar() received several updates that were
never introduced to the function pci_ioremap_wc_bar().

Thus, to align implementation of both functions and reduce the need to
duplicate code between them, introduce a new internal function called
__pci_ioremap_resource() as a helper with a shared codebase intended to
be called from functions pci_ioremap_bar() and pci_ioremap_wc_bar().

The  __pci_ioremap_resource() function will therefore include a check
for the IORESOURCE_UNSET flag that has previously been added to the
function pci_ioremap_bar() in the commit 646c0282df04 ("PCI: Fail
pci_ioremap_bar() on unassigned resources") and otherwise has been
missing from function pci_ioremap_wc_bar().

Additionally, function __pci_ioremap_resource() will retire the usage of
the WARN_ON() macro and replace it with pci_err() to show information
such as the driver name, the BAR number and resource details in case of
a failure, instead of printing a complete backtrace. The WARN_ON() has
already been replaced with pci_warn() in the commit 1f7bf3bfb5d6 ("PCI:
Show driver, BAR#, and resource on pci_ioremap_bar() failure") which
sadly didn't include an update to the function pci_ioremap_wc_bar() at
that time.

Finally, a direct use of functions ioremap() and ioremap_wc() in the
function __pci_ioremap_resource() will be replaced with calls to the
pci_iomap_range() and pci_iomap_wc_range() functions respectively.

Signed-off-by: Krzysztof Wilczyński <kw@linux.com>
---
 drivers/pci/pci.c | 26 ++++++++++++++------------
 1 file changed, 14 insertions(+), 12 deletions(-)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index e3bb0d073352..4bae55f0700b 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -206,7 +206,8 @@ int pci_status_get_and_clear_errors(struct pci_dev *pdev)
 EXPORT_SYMBOL_GPL(pci_status_get_and_clear_errors);
 
 #ifdef CONFIG_HAS_IOMEM
-void __iomem *pci_ioremap_bar(struct pci_dev *pdev, int bar)
+static void __iomem *__pci_ioremap_resource(struct pci_dev *pdev, int bar,
+					    bool write_combine)
 {
 	struct resource *res = &pdev->resource[bar];
 
@@ -214,24 +215,25 @@ void __iomem *pci_ioremap_bar(struct pci_dev *pdev, int bar)
 	 * Make sure the BAR is actually a memory resource, not an IO resource
 	 */
 	if (res->flags & IORESOURCE_UNSET || !(res->flags & IORESOURCE_MEM)) {
-		pci_warn(pdev, "can't ioremap BAR %d: %pR\n", bar, res);
+		pci_err(pdev, "can't ioremap BAR %d: %pR\n", bar, res);
 		return NULL;
 	}
-	return ioremap(res->start, resource_size(res));
+
+	if (write_combine)
+		return pci_iomap_wc_range(pdev, bar, 0, 0);
+
+	return pci_iomap_range(pdev, bar, 0, 0);
+}
+
+void __iomem *pci_ioremap_bar(struct pci_dev *pdev, int bar)
+{
+	return __pci_ioremap_resource(pdev, bar, false);
 }
 EXPORT_SYMBOL_GPL(pci_ioremap_bar);
 
 void __iomem *pci_ioremap_wc_bar(struct pci_dev *pdev, int bar)
 {
-	/*
-	 * Make sure the BAR is actually a memory resource, not an IO resource
-	 */
-	if (!(pci_resource_flags(pdev, bar) & IORESOURCE_MEM)) {
-		WARN_ON(1);
-		return NULL;
-	}
-	return ioremap_wc(pci_resource_start(pdev, bar),
-			  pci_resource_len(pdev, bar));
+	return __pci_ioremap_resource(pdev, bar, true);
 }
 EXPORT_SYMBOL_GPL(pci_ioremap_wc_bar);
 #endif
-- 
2.32.0