| Message ID | 20170327094954.7162-7-lorenzo.pieralisi@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
Hi Russell, On Mon, Mar 27, 2017 at 10:49:34AM +0100, Lorenzo Pieralisi wrote: > The PCI bus specifications (rev 3.0, 3.2.5 "Transaction Ordering > and Posting") define rules for PCI configuration space transactions > ordering and posting, that state that configuration writes have to > be non-posted transactions. > > Current ioremap interface on ARM provides mapping functions that > provide "bufferable" writes transactions (ie ioremap uses MT_DEVICE > memory type) aka posted writes, so PCI host controller drivers have > no arch interface to remap PCI configuration space with memory > attributes that comply with the PCI specifications for configuration > space. > > Implement an ARM specific ioremap_nopost() interface that allows to > map PCI config memory regions with MT_UNCACHED memory type (ie strongly > ordered - non-posted writes), providing a remap function that complies > with PCI specifications for config space transactions. > > Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> > Cc: Arnd Bergmann <arnd@arndb.de> > Cc: Russell King <linux@armlinux.org.uk> > --- > arch/arm/include/asm/io.h | 10 ++++++++++ > arch/arm/mm/ioremap.c | 7 +++++++ > arch/arm/mm/nommu.c | 9 +++++++++ > 3 files changed, 26 insertions(+) I have not added your ACK to this patch since I slightly tweaked it to adapt it to ioremap_nopost() interface instead of a PCI specific one. Furthermore, I mechanically added a ioremap_nopost() version for nommu too in the process, would be good to have a look if I did that properly please. Can I add your ACK on this patch ? If you spot any issues please do let me know. Thank you ! Lorenzo > diff --git a/arch/arm/include/asm/io.h b/arch/arm/include/asm/io.h > index 42871fb..49913d1 100644 > --- a/arch/arm/include/asm/io.h > +++ b/arch/arm/include/asm/io.h > @@ -352,6 +352,7 @@ static inline void memcpy_toio(volatile void __iomem *to, const void *from, > * mapping has specific properties. > * > * Function Memory type Cacheability Cache hint > + * ioremap_nopost() SO n/a n/a > * ioremap() Device n/a n/a > * ioremap_nocache() Device n/a n/a > * ioremap_cache() Normal Writeback Read allocate > @@ -372,6 +373,12 @@ static inline void memcpy_toio(volatile void __iomem *to, const void *from, > * compiler may generate unaligned accesses - eg, via inlining its own > * memcpy. > * > + * ioremap_nopost() maps memory as strongly ordered, to be used for > + * specific mappings (eg PCI config space) that require non-posted > + * write transactions. Strongly ordered transactions are ordered wrt > + * device mappings, which means that ioremap_nopost() is the same > + * as ioremap() except for non-posted writes behaviour. > + * > * All normal memory mappings have the following properties: > * - reads can be repeated with no side effects > * - repeated reads return the last value written > @@ -407,6 +414,9 @@ void __iomem *ioremap_wc(resource_size_t res_cookie, size_t size); > #define ioremap_wc ioremap_wc > #define ioremap_wt ioremap_wc > > +void __iomem *ioremap_nopost(resource_size_t res_cookie, size_t size); > +#define ioremap_nopost ioremap_nopost > + > void iounmap(volatile void __iomem *iomem_cookie); > #define iounmap iounmap > > diff --git a/arch/arm/mm/ioremap.c b/arch/arm/mm/ioremap.c > index ff0eed2..4ffaf16 100644 > --- a/arch/arm/mm/ioremap.c > +++ b/arch/arm/mm/ioremap.c > @@ -463,6 +463,13 @@ void iounmap(volatile void __iomem *cookie) > } > EXPORT_SYMBOL(iounmap); > > +void __iomem *ioremap_nopost(resource_size_t res_cookie, size_t size) > +{ > + return arch_ioremap_caller(res_cookie, size, MT_UNCACHED, > + __builtin_return_address(0)); > +} > +EXPORT_SYMBOL_GPL(ioremap_nopost); > + > #ifdef CONFIG_PCI > static int pci_ioremap_mem_type = MT_DEVICE; > > diff --git a/arch/arm/mm/nommu.c b/arch/arm/mm/nommu.c > index 3b5c7aa..dfd736a 100644 > --- a/arch/arm/mm/nommu.c > +++ b/arch/arm/mm/nommu.c > @@ -21,6 +21,8 @@ > #include <asm/mpu.h> > #include <asm/procinfo.h> > > +#include <asm/mach/map.h> > + > #include "mm.h" > > unsigned long vectors_base; > @@ -433,6 +435,13 @@ void __iomem *ioremap_wc(resource_size_t res_cookie, size_t size) > } > EXPORT_SYMBOL(ioremap_wc); > > +void __iomem *ioremap_nopost(resource_size_t res_cookie, size_t size) > +{ > + return __arm_ioremap_caller(res_cookie, size, MT_UNCACHED, > + __builtin_return_address(0)); > +} > +EXPORT_SYMBOL(ioremap_nopost); > + > void *arch_memremap_wb(phys_addr_t phys_addr, size_t size) > { > return (void *)phys_addr; > -- > 2.10.0 >
On Fri, Mar 31, 2017 at 12:08:13PM +0100, Lorenzo Pieralisi wrote: > Hi Russell, > > On Mon, Mar 27, 2017 at 10:49:34AM +0100, Lorenzo Pieralisi wrote: > > The PCI bus specifications (rev 3.0, 3.2.5 "Transaction Ordering > > and Posting") define rules for PCI configuration space transactions > > ordering and posting, that state that configuration writes have to > > be non-posted transactions. > > > > Current ioremap interface on ARM provides mapping functions that > > provide "bufferable" writes transactions (ie ioremap uses MT_DEVICE > > memory type) aka posted writes, so PCI host controller drivers have > > no arch interface to remap PCI configuration space with memory > > attributes that comply with the PCI specifications for configuration > > space. > > > > Implement an ARM specific ioremap_nopost() interface that allows to > > map PCI config memory regions with MT_UNCACHED memory type (ie strongly > > ordered - non-posted writes), providing a remap function that complies > > with PCI specifications for config space transactions. > > > > Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> > > Cc: Arnd Bergmann <arnd@arndb.de> > > Cc: Russell King <linux@armlinux.org.uk> > > --- > > arch/arm/include/asm/io.h | 10 ++++++++++ > > arch/arm/mm/ioremap.c | 7 +++++++ > > arch/arm/mm/nommu.c | 9 +++++++++ > > 3 files changed, 26 insertions(+) > > I have not added your ACK to this patch since I slightly tweaked > it to adapt it to ioremap_nopost() interface instead of a PCI > specific one. Furthermore, I mechanically added a ioremap_nopost() > version for nommu too in the process, would be good to have a look > if I did that properly please. > > Can I add your ACK on this patch ? If you spot any issues please > do let me know. Hi Russell, please let me know if your ACK on this patch stands as I have to respin it shortly for hopefully final round of review. Thanks ! Lorenzo > Thank you ! > Lorenzo > > > diff --git a/arch/arm/include/asm/io.h b/arch/arm/include/asm/io.h > > index 42871fb..49913d1 100644 > > --- a/arch/arm/include/asm/io.h > > +++ b/arch/arm/include/asm/io.h > > @@ -352,6 +352,7 @@ static inline void memcpy_toio(volatile void __iomem *to, const void *from, > > * mapping has specific properties. > > * > > * Function Memory type Cacheability Cache hint > > + * ioremap_nopost() SO n/a n/a > > * ioremap() Device n/a n/a > > * ioremap_nocache() Device n/a n/a > > * ioremap_cache() Normal Writeback Read allocate > > @@ -372,6 +373,12 @@ static inline void memcpy_toio(volatile void __iomem *to, const void *from, > > * compiler may generate unaligned accesses - eg, via inlining its own > > * memcpy. > > * > > + * ioremap_nopost() maps memory as strongly ordered, to be used for > > + * specific mappings (eg PCI config space) that require non-posted > > + * write transactions. Strongly ordered transactions are ordered wrt > > + * device mappings, which means that ioremap_nopost() is the same > > + * as ioremap() except for non-posted writes behaviour. > > + * > > * All normal memory mappings have the following properties: > > * - reads can be repeated with no side effects > > * - repeated reads return the last value written > > @@ -407,6 +414,9 @@ void __iomem *ioremap_wc(resource_size_t res_cookie, size_t size); > > #define ioremap_wc ioremap_wc > > #define ioremap_wt ioremap_wc > > > > +void __iomem *ioremap_nopost(resource_size_t res_cookie, size_t size); > > +#define ioremap_nopost ioremap_nopost > > + > > void iounmap(volatile void __iomem *iomem_cookie); > > #define iounmap iounmap > > > > diff --git a/arch/arm/mm/ioremap.c b/arch/arm/mm/ioremap.c > > index ff0eed2..4ffaf16 100644 > > --- a/arch/arm/mm/ioremap.c > > +++ b/arch/arm/mm/ioremap.c > > @@ -463,6 +463,13 @@ void iounmap(volatile void __iomem *cookie) > > } > > EXPORT_SYMBOL(iounmap); > > > > +void __iomem *ioremap_nopost(resource_size_t res_cookie, size_t size) > > +{ > > + return arch_ioremap_caller(res_cookie, size, MT_UNCACHED, > > + __builtin_return_address(0)); > > +} > > +EXPORT_SYMBOL_GPL(ioremap_nopost); > > + > > #ifdef CONFIG_PCI > > static int pci_ioremap_mem_type = MT_DEVICE; > > > > diff --git a/arch/arm/mm/nommu.c b/arch/arm/mm/nommu.c > > index 3b5c7aa..dfd736a 100644 > > --- a/arch/arm/mm/nommu.c > > +++ b/arch/arm/mm/nommu.c > > @@ -21,6 +21,8 @@ > > #include <asm/mpu.h> > > #include <asm/procinfo.h> > > > > +#include <asm/mach/map.h> > > + > > #include "mm.h" > > > > unsigned long vectors_base; > > @@ -433,6 +435,13 @@ void __iomem *ioremap_wc(resource_size_t res_cookie, size_t size) > > } > > EXPORT_SYMBOL(ioremap_wc); > > > > +void __iomem *ioremap_nopost(resource_size_t res_cookie, size_t size) > > +{ > > + return __arm_ioremap_caller(res_cookie, size, MT_UNCACHED, > > + __builtin_return_address(0)); > > +} > > +EXPORT_SYMBOL(ioremap_nopost); > > + > > void *arch_memremap_wb(phys_addr_t phys_addr, size_t size) > > { > > return (void *)phys_addr; > > -- > > 2.10.0 > >
diff --git a/arch/arm/include/asm/io.h b/arch/arm/include/asm/io.h index 42871fb..49913d1 100644 --- a/arch/arm/include/asm/io.h +++ b/arch/arm/include/asm/io.h @@ -352,6 +352,7 @@ static inline void memcpy_toio(volatile void __iomem *to, const void *from, * mapping has specific properties. * * Function Memory type Cacheability Cache hint + * ioremap_nopost() SO n/a n/a * ioremap() Device n/a n/a * ioremap_nocache() Device n/a n/a * ioremap_cache() Normal Writeback Read allocate @@ -372,6 +373,12 @@ static inline void memcpy_toio(volatile void __iomem *to, const void *from, * compiler may generate unaligned accesses - eg, via inlining its own * memcpy. * + * ioremap_nopost() maps memory as strongly ordered, to be used for + * specific mappings (eg PCI config space) that require non-posted + * write transactions. Strongly ordered transactions are ordered wrt + * device mappings, which means that ioremap_nopost() is the same + * as ioremap() except for non-posted writes behaviour. + * * All normal memory mappings have the following properties: * - reads can be repeated with no side effects * - repeated reads return the last value written @@ -407,6 +414,9 @@ void __iomem *ioremap_wc(resource_size_t res_cookie, size_t size); #define ioremap_wc ioremap_wc #define ioremap_wt ioremap_wc +void __iomem *ioremap_nopost(resource_size_t res_cookie, size_t size); +#define ioremap_nopost ioremap_nopost + void iounmap(volatile void __iomem *iomem_cookie); #define iounmap iounmap diff --git a/arch/arm/mm/ioremap.c b/arch/arm/mm/ioremap.c index ff0eed2..4ffaf16 100644 --- a/arch/arm/mm/ioremap.c +++ b/arch/arm/mm/ioremap.c @@ -463,6 +463,13 @@ void iounmap(volatile void __iomem *cookie) } EXPORT_SYMBOL(iounmap); +void __iomem *ioremap_nopost(resource_size_t res_cookie, size_t size) +{ + return arch_ioremap_caller(res_cookie, size, MT_UNCACHED, + __builtin_return_address(0)); +} +EXPORT_SYMBOL_GPL(ioremap_nopost); + #ifdef CONFIG_PCI static int pci_ioremap_mem_type = MT_DEVICE; diff --git a/arch/arm/mm/nommu.c b/arch/arm/mm/nommu.c index 3b5c7aa..dfd736a 100644 --- a/arch/arm/mm/nommu.c +++ b/arch/arm/mm/nommu.c @@ -21,6 +21,8 @@ #include <asm/mpu.h> #include <asm/procinfo.h> +#include <asm/mach/map.h> + #include "mm.h" unsigned long vectors_base; @@ -433,6 +435,13 @@ void __iomem *ioremap_wc(resource_size_t res_cookie, size_t size) } EXPORT_SYMBOL(ioremap_wc); +void __iomem *ioremap_nopost(resource_size_t res_cookie, size_t size) +{ + return __arm_ioremap_caller(res_cookie, size, MT_UNCACHED, + __builtin_return_address(0)); +} +EXPORT_SYMBOL(ioremap_nopost); + void *arch_memremap_wb(phys_addr_t phys_addr, size_t size) { return (void *)phys_addr;
The PCI bus specifications (rev 3.0, 3.2.5 "Transaction Ordering and Posting") define rules for PCI configuration space transactions ordering and posting, that state that configuration writes have to be non-posted transactions. Current ioremap interface on ARM provides mapping functions that provide "bufferable" writes transactions (ie ioremap uses MT_DEVICE memory type) aka posted writes, so PCI host controller drivers have no arch interface to remap PCI configuration space with memory attributes that comply with the PCI specifications for configuration space. Implement an ARM specific ioremap_nopost() interface that allows to map PCI config memory regions with MT_UNCACHED memory type (ie strongly ordered - non-posted writes), providing a remap function that complies with PCI specifications for config space transactions. Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Russell King <linux@armlinux.org.uk> --- arch/arm/include/asm/io.h | 10 ++++++++++ arch/arm/mm/ioremap.c | 7 +++++++ arch/arm/mm/nommu.c | 9 +++++++++ 3 files changed, 26 insertions(+)