The implementation of pci_iounmap() is currently scattered over two
files, drivers/pci/iomap.c and lib/iomap.c. Additionally,
architectures can define their own version.
To have only one version, it's necessary to create a helper function,
iomem_is_ioport(), that tells pci_iounmap() whether the passed address
points to an ioport or normal memory.
iomem_is_ioport() can be provided through two different ways:
1. The architecture itself provides it. As of today, the version
coming from lib/iomap.c de facto is the x86-specific version and
comes into play when CONFIG_GENERIC_IOMAP is selected. This rather
confusing naming is an artifact left by the removal of IA64.
2. As a default version in include/asm-generic/io.h for those
architectures that don't use CONFIG_GENERIC_IOMAP, but also don't
provide their own version of iomem_is_ioport().
Once all architectures that support ports provide iomem_is_ioport(), the
arch-specific definitions for pci_iounmap() can be removed and the archs
can use the generic implementation, instead.
Create a unified version of pci_iounmap() in drivers/pci/iomap.c.
Provide the function iomem_is_ioport() in include/asm-generic/io.h
(generic) and lib/iomap.c ("pseudo-generic" for x86).
Remove the CONFIG_GENERIC_IOMAP guard around
ARCH_WANTS_GENERIC_PCI_IOUNMAP so that configs that set
CONFIG_GENERIC_PCI_IOMAP without CONFIG_GENERIC_IOMAP still get the
function.
Add TODOs for follow-up work on the "generic is not generic but
x86-spcific"-Problem.
Suggested-by: Arnd Bergmann <arnd@xxxxxxxxxx>
Signed-off-by: Philipp Stanner <pstanner@xxxxxxxxxx>
---
drivers/pci/iomap.c | 46 ++++++++++++-------------------------
include/asm-generic/io.h | 27 ++++++++++++++++++++--
include/asm-generic/iomap.h | 21 +++++++++++++++++
lib/iomap.c | 28 ++++++++++++++++------
4 files changed, 82 insertions(+), 40 deletions(-)
diff --git a/drivers/pci/iomap.c b/drivers/pci/iomap.c
index 91285fcff1ba..439ba2e9710f 100644
--- a/drivers/pci/iomap.c
+++ b/drivers/pci/iomap.c
@@ -135,44 +135,28 @@ void __iomem *pci_iomap_wc(struct pci_dev *dev, int bar, unsigned long maxlen)
EXPORT_SYMBOL_GPL(pci_iomap_wc);
/*
- * pci_iounmap() somewhat illogically comes from lib/iomap.c for the
- * CONFIG_GENERIC_IOMAP case, because that's the code that knows about
- * the different IOMAP ranges.
+ * This check is still necessary due to legacy reasons.
*
- * But if the architecture does not use the generic iomap code, and if
- * it has _not_ defined it's own private pci_iounmap function, we define
- * it here.
- *
- * NOTE! This default implementation assumes that if the architecture
- * support ioport mapping (HAS_IOPORT_MAP), the ioport mapping will
- * be fixed to the range [ PCI_IOBASE, PCI_IOBASE+IO_SPACE_LIMIT [,
- * and does not need unmapping with 'ioport_unmap()'.
- *
- * If you have different rules for your architecture, you need to
- * implement your own pci_iounmap() that knows the rules for where
- * and how IO vs MEM get mapped.
- *
- * This code is odd, and the ARCH_HAS/ARCH_WANTS #define logic comes
- * from legacy <asm-generic/io.h> header file behavior. In particular,
- * it would seem to make sense to do the iounmap(p) for the non-IO-space
- * case here regardless, but that's not what the old header file code
- * did. Probably incorrectly, but this is meant to be bug-for-bug
- * compatible.
+ * TODO: Have all architectures that provide their own pci_iounmap() provide
+ * iomem_is_ioport() instead. Remove this #if afterwards.
*/
#if defined(ARCH_WANTS_GENERIC_PCI_IOUNMAP)
-void pci_iounmap(struct pci_dev *dev, void __iomem *p)
+/**
+ * pci_iounmap - Unmapp a mapping
+ * @dev: PCI device the mapping belongs to
+ * @addr: start address of the mapping
+ *
+ * Unmapp a PIO or MMIO mapping.
+ */
+void pci_iounmap(struct pci_dev *dev, void __iomem *addr)
{
-#ifdef ARCH_HAS_GENERIC_IOPORT_MAP
- uintptr_t start = (uintptr_t) PCI_IOBASE;
- uintptr_t addr = (uintptr_t) p;
-
- if (addr >= start && addr < start + IO_SPACE_LIMIT) {
- ioport_unmap(p);
+ if (iomem_is_ioport(addr)) {
+ ioport_unmap(addr);
return;
}
-#endif
- iounmap(p);
+
+ iounmap(addr);
}
EXPORT_SYMBOL(pci_iounmap);
diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h
index bac63e874c7b..58c7bf4080da 100644
--- a/include/asm-generic/io.h
+++ b/include/asm-generic/io.h
@@ -1129,11 +1129,34 @@ extern void ioport_unmap(void __iomem *p);
#endif /* CONFIG_GENERIC_IOMAP */
#endif /* CONFIG_HAS_IOPORT_MAP */
-#ifndef CONFIG_GENERIC_IOMAP
+/*
+ * TODO:
+ * remove this once all architectures replaced their pci_iounmap() with
+ * a custom implementation of iomem_is_ioport().
+ */
#ifndef pci_iounmap
+#define pci_iounmap pci_iounmap
#define ARCH_WANTS_GENERIC_PCI_IOUNMAP
+#endif /* pci_iounmap */
+
+/*
+ * This function is a helper only needed for the generic pci_iounmap().
+ * It's provided here if the architecture does not provide its own version.
+ */
+#ifndef iomem_is_ioport
+#define iomem_is_ioport iomem_is_ioport
+static inline bool iomem_is_ioport(void __iomem *addr_raw)
+{
+#ifdef CONFIG_HAS_IOPORT
+ uintptr_t start = (uintptr_t)PCI_IOBASE;
+ uintptr_t addr = (uintptr_t)addr_raw;
+
+ if (addr >= start && addr < start + IO_SPACE_LIMIT)
+ return true;
#endif
-#endif
+ return false;
+}
+#endif /* iomem_is_ioport */
#ifndef xlate_dev_mem_ptr
#define xlate_dev_mem_ptr xlate_dev_mem_ptr
diff --git a/include/asm-generic/iomap.h b/include/asm-generic/iomap.h
index 196087a8126e..2cdc6988a102 100644
--- a/include/asm-generic/iomap.h
+++ b/include/asm-generic/iomap.h
@@ -110,6 +110,27 @@ static inline void __iomem *ioremap_np(phys_addr_t offset, size_t size)
}
#endif
+/*
+ * If CONFIG_GENERIC_IOMAP is selected and the architecture does NOT provide its
+ * own version, ARCH_WANTS_GENERIC_IOMEM_IS_IOPORT makes sure that the generic
+ * version from asm-generic/io.h is NOT used and instead the second "generic"
+ * version from lib/iomap.c is used.
+ *
+ * There are currently two generic versions because of a difficult cleanup
+ * process. Namely, the version in lib/iomap.c once was really generic when IA64
+ * still existed. Today, it's only really used by x86.
+ *
+ * TODO: Move the version from lib/iomap.c to x86 specific code. Then, remove
+ * this ARCH_WANTS_GENERIC_IOMEM_IS_IOPORT-mechanism.
+ */
+#ifdef CONFIG_GENERIC_IOMAP
+#ifndef iomem_is_ioport
+#define iomem_is_ioport iomem_is_ioport
+bool iomem_is_ioport(void __iomem *addr);
+#define ARCH_WANTS_GENERIC_IOMEM_IS_IOPORT
+#endif /* iomem_is_ioport */
+#endif /* CONFIG_GENERIC_IOMAP */
+
#include <asm-generic/pci_iomap.h>
#endif
diff --git a/lib/iomap.c b/lib/iomap.c
index 4f8b31baa575..eb9a879ebf42 100644
--- a/lib/iomap.c
+++ b/lib/iomap.c
@@ -418,12 +418,26 @@ EXPORT_SYMBOL(ioport_map);
EXPORT_SYMBOL(ioport_unmap);
#endif /* CONFIG_HAS_IOPORT_MAP */
-#ifdef CONFIG_PCI
-/* Hide the details if this is a MMIO or PIO address space and just do what
- * you expect in the correct way. */
-void pci_iounmap(struct pci_dev *dev, void __iomem * addr)
+/*
+ * If CONFIG_GENERIC_IOMAP is selected and the architecture does NOT provide its
+ * own version, ARCH_WANTS_GENERIC_IOMEM_IS_IOPORT makes sure that the generic
+ * version from asm-generic/io.h is NOT used and instead the second "generic"
+ * version from this file here is used.
+ *
+ * There are currently two generic versions because of a difficult cleanup
+ * process. Namely, the version in lib/iomap.c once was really generic when IA64
+ * still existed. Today, it's only really used by x86.
+ *
+ * TODO: Move this function to x86-specific code.
+ */
+#if defined(ARCH_WANTS_GENERIC_IOMEM_IS_IOPORT)
+bool iomem_is_ioport(void __iomem *addr)
{
- IO_COND(addr, /* nothing */, iounmap(addr));
+ unsigned long port = (unsigned long __force)addr;
+
+ if (port > PIO_OFFSET && port < PIO_RESERVED)
+ return true;
+
+ return false;
}
-EXPORT_SYMBOL(pci_iounmap);
-#endif /* CONFIG_PCI */
+#endif /* ARCH_WANTS_GENERIC_IOMEM_IS_IOPORT */
--
2.43.0
