Re: [PATCH v2 07/11] openrisc: mm: Convert to GENERIC_IOREMAP

Stafford Horne
2022-08-29T06:42:19Z

On Mon, Aug 29, 2022 at 09:40:24AM +0800, Baoquan He wrote:
> On 08/21/22 at 12:03am, Christoph Hellwig wrote:
> > > + if (unlikely(!mem_init_done)) {
> > > if ((fixmaps_used + (size >> PAGE_SHIFT)) > FIX_N_IOREMAPS)
> > > + return IOMEM_ERR_PTR(ret);
> > > v = fix_to_virt(FIX_IOREMAP_BEGIN + fixmaps_used);
> > > fixmaps_used += (size >> PAGE_SHIFT);
> > >
> > > + if (ioremap_page_range(v, v + size, p, __pgprot(*prot_val))) {
> > > fixmaps_used -= (size >> PAGE_SHIFT);
> > > + return IOMEM_ERR_PTR(ret);
> > > + }
> > > +
> > > + return (void __iomem *)(offset + (char *)v);
> > > }
> >
> > This code needs to go away, and all very early boot uses of ioremap
> > need to switch to use early_ioremap insted.
>
> Makes sense. On openrisc, the thing is I didn't find one place where
> ioremap() is called in arch code. I can cut the early ioremap out and
> wrap into a separate early_ioremap() function, however I don't know
> where to put it. Not sure if I miss anything or openrisc doesn't really
> need early ioremap.

Hi,

I don't know of any early_ioremap usage either in openrisc, maybe some drivers
use it? However, we do not initialize any early_ioremap infrastructure in
openrisc so that may cause issues if it is used.

We can try to remove it all. I tested these below additional changes and they
work, if you want to add them we can see if kbuild robots pick anything up.

-Stafford

diff --git a/arch/openrisc/mm/ioremap.c b/arch/openrisc/mm/ioremap.c
index bc41660e1fb0..ffe6d5e2b5fe 100644
--- a/arch/openrisc/mm/ioremap.c
+++ b/arch/openrisc/mm/ioremap.c
@@ -22,14 +22,10 @@

extern int mem_init_done;

-static unsigned int fixmaps_used __initdata;
-
void __iomem *
arch_ioremap(phys_addr_t *paddr, size_t size, unsigned long *prot_val)
{
- phys_addr_t p;
- unsigned long v;
- unsigned long offset, last_addr, addr = *paddr;
+ unsigned long last_addr, addr = *paddr;
int ret = -EINVAL;

/* Don't allow wraparound or zero size */
@@ -37,27 +33,6 @@ arch_ioremap(phys_addr_t *paddr, size_t size, unsigned long *prot_val)
if (!size || last_addr < addr)
return IOMEM_ERR_PTR(ret);

- /*
- * Mappings have to be page-aligned
- */
- offset = addr & ~PAGE_MASK;
- p = addr & PAGE_MASK;
- size = PAGE_ALIGN(last_addr + 1) - p;
-
- if (unlikely(!mem_init_done)) {
- if ((fixmaps_used + (size >> PAGE_SHIFT)) > FIX_N_IOREMAPS)
- return IOMEM_ERR_PTR(ret);
- v = fix_to_virt(FIX_IOREMAP_BEGIN + fixmaps_used);
- fixmaps_used += (size >> PAGE_SHIFT);
-
- if (ioremap_page_range(v, v + size, p, __pgprot(*prot_val))) {
- fixmaps_used -= (size >> PAGE_SHIFT);
- return IOMEM_ERR_PTR(ret);
- }
-
- return (void __iomem *)(offset + (char *)v);
- }
-
return NULL;
}