[RFC PATCH] powerpc: add ioremap_wt

[Michael Moese]

Allow for IO memory to be mapped cacheable for performing
PCI read bursts.

Signed-off-by: Michael Moese 
---
 arch/powerpc/include/asm/io.h | 3 +++
 arch/powerpc/mm/pgtable_32.c  | 8 
 2 files changed, 11 insertions(+)

diff --git a/arch/powerpc/include/asm/io.h b/arch/powerpc/include/asm/io.h
index 45698d5..9591fff 100644
--- a/arch/powerpc/include/asm/io.h
+++ b/arch/powerpc/include/asm/io.h
@@ -631,6 +631,8 @@ static inline void iosync(void)
  *
  * * ioremap_wc enables write combining
  *
+ * * ioremap_wc enables write thru
+ *
  * * iounmap undoes such a mapping and can be hooked
  *
  * * __ioremap_at (and the pending __iounmap_at) are low level functions to
@@ -652,6 +654,7 @@ extern void __iomem *ioremap(phys_addr_t address, unsigned 
long size);
 extern void __iomem *ioremap_prot(phys_addr_t address, unsigned long size,
  unsigned long flags);
 extern void __iomem *ioremap_wc(phys_addr_t address, unsigned long size);
+extern void __iomem *ioremap_wt(phys_addr_t address, unsigned long size);
 #define ioremap_nocache(addr, size)ioremap((addr), (size))
 
 extern void iounmap(volatile void __iomem *addr);
diff --git a/arch/powerpc/mm/pgtable_32.c b/arch/powerpc/mm/pgtable_32.c
index 51f8795..9ab0a54 100644
--- a/arch/powerpc/mm/pgtable_32.c
+++ b/arch/powerpc/mm/pgtable_32.c
@@ -141,6 +141,14 @@ ioremap_wc(phys_addr_t addr, unsigned long size)
 EXPORT_SYMBOL(ioremap_wc);
 
 void __iomem *
+ioremap_wt(phys_addr_t addr, unsigned long size)
+{
+   return __ioremap_caller(addr, size, _PAGE_WRITETHRU,
+   __builtin_return_address(0));
+}
+EXPORT_SYMBOL(ioremap_wt);
+
+void __iomem *
 ioremap_prot(phys_addr_t addr, unsigned long size, unsigned long flags)
 {
/* writeable implies dirty for kernel addresses */
-- 
1.8.5.3

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Re: [git pull] Please pull powerpc.git next branch

[Michael Ellerman]

On Wed, 2014-01-29 at 13:29 +1100, Alistair Popple wrote:
> Looks like I missed the dart iommu code when changing the iommu table
> initialisation. The patch below should fix it, would you mind testing
> it Ben? Thanks.

Any reason not to add the following to save ourselves in future?

diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
index d773dd4..6ab7b53 100644
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c
@@ -657,6 +657,8 @@ struct iommu_table *iommu_init_table(struct iommu_table 
*tbl, int nid)
unsigned int i;
struct iommu_pool *p;
 
+   BUG_ON(!tbl->it_page_shift);
+
/* number of bytes needed for the bitmap */
sz = BITS_TO_LONGS(tbl->it_size) * sizeof(unsigned long);
 

cheers



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