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Merge tag 'for-linus' of https://github.com/openrisc/linux
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Pull OpenRISC update from Stafford Horne:
 "A single fixup from me: Fix bug with earlycon being broken due to
  removal of early_ioremap"

* tag 'for-linus' of https://github.com/openrisc/linux:
  openrisc: Implement fixmap to fix earlycon
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torvalds committed Nov 20, 2024
2 parents f103749 + 1037d18 commit c66fbc6
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Showing 3 changed files with 45 additions and 16 deletions.
3 changes: 3 additions & 0 deletions arch/openrisc/Kconfig
Original file line number Diff line number Diff line change
Expand Up @@ -65,6 +65,9 @@ config STACKTRACE_SUPPORT
config LOCKDEP_SUPPORT
def_bool y

config FIX_EARLYCON_MEM
def_bool y

menu "Processor type and features"

choice
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21 changes: 5 additions & 16 deletions arch/openrisc/include/asm/fixmap.h
Original file line number Diff line number Diff line change
Expand Up @@ -26,29 +26,18 @@
#include <linux/bug.h>
#include <asm/page.h>

/*
* On OpenRISC we use these special fixed_addresses for doing ioremap
* early in the boot process before memory initialization is complete.
* This is used, in particular, by the early serial console code.
*
* It's not really 'fixmap', per se, but fits loosely into the same
* paradigm.
*/
enum fixed_addresses {
/*
* FIX_IOREMAP entries are useful for mapping physical address
* space before ioremap() is useable, e.g. really early in boot
* before kmalloc() is working.
*/
#define FIX_N_IOREMAPS 32
FIX_IOREMAP_BEGIN,
FIX_IOREMAP_END = FIX_IOREMAP_BEGIN + FIX_N_IOREMAPS - 1,
FIX_EARLYCON_MEM_BASE,
__end_of_fixed_addresses
};

#define FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT)
/* FIXADDR_BOTTOM might be a better name here... */
#define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE)
#define FIXMAP_PAGE_IO PAGE_KERNEL_NOCACHE

extern void __set_fixmap(enum fixed_addresses idx,
phys_addr_t phys, pgprot_t flags);

#include <asm-generic/fixmap.h>

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37 changes: 37 additions & 0 deletions arch/openrisc/mm/init.c
Original file line number Diff line number Diff line change
Expand Up @@ -207,6 +207,43 @@ void __init mem_init(void)
return;
}

static int __init map_page(unsigned long va, phys_addr_t pa, pgprot_t prot)
{
p4d_t *p4d;
pud_t *pud;
pmd_t *pmd;
pte_t *pte;

p4d = p4d_offset(pgd_offset_k(va), va);
pud = pud_offset(p4d, va);
pmd = pmd_offset(pud, va);
pte = pte_alloc_kernel(pmd, va);

if (pte == NULL)
return -ENOMEM;

if (pgprot_val(prot))
set_pte_at(&init_mm, va, pte, pfn_pte(pa >> PAGE_SHIFT, prot));
else
pte_clear(&init_mm, va, pte);

local_flush_tlb_page(NULL, va);
return 0;
}

void __init __set_fixmap(enum fixed_addresses idx,
phys_addr_t phys, pgprot_t prot)
{
unsigned long address = __fix_to_virt(idx);

if (idx >= __end_of_fixed_addresses) {
BUG();
return;
}

map_page(address, phys, prot);
}

static const pgprot_t protection_map[16] = {
[VM_NONE] = PAGE_NONE,
[VM_READ] = PAGE_READONLY_X,
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