Commit 7c566bb5 authored by Hector Martin's avatar Hector Martin
Browse files

asm-generic/io.h: Add a non-posted variant of ioremap() 



ARM64 currently defaults to posted MMIO (nGnRE), but some devices
require the use of non-posted MMIO (nGnRnE). Introduce a new ioremap()
variant to handle this case. ioremap_np() returns NULL on arches that
do not implement this variant.

sparc64 is the only architecture that needs to be touched directly,
because it includes neither of the generic io.h or iomap.h headers.

This adds the IORESOURCE_MEM_NONPOSTED flag, which maps to this
variant and marks a given resource as requiring non-posted mappings.
This is implemented in the resource system because it is a SoC-level
requirement, so existing drivers do not need special-case code to pick
this ioremap variant.

Then this is implemented in devres by introducing devm_ioremap_np(),
and making devm_ioremap_resource() automatically select this variant
when the resource has the IORESOURCE_MEM_NONPOSTED flag set.

Acked-by: default avatarMarc Zyngier <maz@kernel.org>
Signed-off-by: default avatarHector Martin <marcan@marcan.st>
parent 86332e9e

Documentation/driver-api/driver-model/devres.rst

+1 −0
Original line number Diff line number Diff line
@@ -309,6 +309,7 @@ IOMAP 
  devm_ioremap()

  devm_ioremap_uc()

  devm_ioremap_wc()

  devm_ioremap_np()

  devm_ioremap_resource() : checks resource, requests memory region, ioremaps

  devm_ioremap_resource_wc()

  devm_platform_ioremap_resource() : calls devm_ioremap_resource() for platform device

arch/sparc/include/asm/io_64.h

+4 −0
Original line number Diff line number Diff line
@@ -409,6 +409,10 @@ static inline void __iomem *ioremap(unsigned long offset, unsigned long size) 
#define ioremap_uc(X,Y)			ioremap((X),(Y))

#define ioremap_wc(X,Y)			ioremap((X),(Y))

#define ioremap_wt(X,Y)			ioremap((X),(Y))

static inline void __iomem *ioremap_np(unsigned long offset, unsigned long size)

{

	return NULL;

}



static inline void iounmap(volatile void __iomem *addr)

{

include/asm-generic/io.h

+21 −1
Original line number Diff line number Diff line
@@ -942,7 +942,9 @@ static inline void *phys_to_virt(unsigned long address) 
 *

 * ioremap_wc() and ioremap_wt() can provide more relaxed caching attributes

 * for specific drivers if the architecture choses to implement them.  If they

 * are not implemented we fall back to plain ioremap.

 * are not implemented we fall back to plain ioremap. Conversely, ioremap_np()

 * can provide stricter non-posted write semantics if the architecture

 * implements them.

 */

#ifndef CONFIG_MMU

#ifndef ioremap
@@ -993,6 +995,24 @@ static inline void __iomem *ioremap_uc(phys_addr_t offset, size_t size) 
{

	return NULL;

}



/*

 * ioremap_np needs an explicit architecture implementation, as it

 * requests stronger semantics than regular ioremap(). Portable drivers

 * should instead use one of the higher-level abstractions, like

 * devm_ioremap_resource(), to choose the correct variant for any given

 * device and bus. Portable drivers with a good reason to want non-posted

 * write semantics should always provide an ioremap() fallback in case

 * ioremap_np() is not available.

 */

#ifndef ioremap_np

#define ioremap_np ioremap_np

static inline void __iomem *ioremap_np(phys_addr_t offset, size_t size)

{

	return NULL;

}

#endif



#endif



#ifdef CONFIG_HAS_IOPORT_MAP

include/asm-generic/iomap.h

+9 −0
Original line number Diff line number Diff line
@@ -101,6 +101,15 @@ extern void ioport_unmap(void __iomem *); 
#define ioremap_wt ioremap

#endif



#ifndef ARCH_HAS_IOREMAP_NP

/* See the comment in asm-generic/io.h about ioremap_np(). */

#define ioremap_np ioremap_np

static inline void __iomem *ioremap_np(phys_addr_t offset, size_t size)

{

	return NULL;

}

#endif



#ifdef CONFIG_PCI

/* Destroy a virtual mapping cookie for a PCI BAR (memory or IO) */

struct pci_dev;

include/linux/io.h

+2 −0
Original line number Diff line number Diff line
@@ -68,6 +68,8 @@ void __iomem *devm_ioremap_uc(struct device *dev, resource_size_t offset, 
				   resource_size_t size);

void __iomem *devm_ioremap_wc(struct device *dev, resource_size_t offset,

				   resource_size_t size);

void __iomem *devm_ioremap_np(struct device *dev, resource_size_t offset,

				   resource_size_t size);

void devm_iounmap(struct device *dev, void __iomem *addr);

int check_signature(const volatile void __iomem *io_addr,

			const unsigned char *signature, int length);