From: Rob Herring <[email protected]> When using DEBUG_LL, the UART's (or other HW's) registers are mapped into early page tables based on the results of assembly macro addruart. Later, when the page tables are replaced, the same virtual address must remain valid. Historically, this has been ensured by using defines from <mach/iomap.h> in both the implementation of addruart, and the machine's .map_io() function. However, with the move to single zImage, we wish to remove <mach/iomap.h>. To enable this, the macro addruart may be used when constructing the late page tables too; addruart is exposed as a C function debug_ll_addr(), and used to set up the required mapping in debug_ll_io_init(), which may called on an opt-in basis from a machine's .map_io() function.
Signed-off-by: Rob Herring <[email protected]> [swarren: Mask map.virtual with PAGE_MASK. Checked for NULL results from debug_ll_addr (e.g. when selected UART isn't valid). Fixed compile when either !CONFIG_DEBUG_LL or CONFIG_DEBUG_SEMIHOSTING.] Signed-off-by: Stephen Warren <[email protected]> --- This patch is a dependency for the Tegra debug-macro.S rework. I assume it should go into some arm-soc branch so that if others want to take advantage of it this kernel cycle, they can. v4: Fix DEBUG_SEMIHOSTING's debug_ll_addr to actually fill in the "out" parameters. v3: New patch. --- arch/arm/include/asm/mach/map.h | 7 +++++++ arch/arm/kernel/debug.S | 14 ++++++++++++++ arch/arm/mm/mmu.c | 16 ++++++++++++++++ 3 files changed, 37 insertions(+), 0 deletions(-) diff --git a/arch/arm/include/asm/mach/map.h b/arch/arm/include/asm/mach/map.h index 195ac2f..2fe141f 100644 --- a/arch/arm/include/asm/mach/map.h +++ b/arch/arm/include/asm/mach/map.h @@ -40,6 +40,13 @@ extern void iotable_init(struct map_desc *, int); extern void vm_reserve_area_early(unsigned long addr, unsigned long size, void *caller); +#ifdef CONFIG_DEBUG_LL +extern void debug_ll_addr(unsigned long *paddr, unsigned long *vaddr); +extern void debug_ll_io_init(void); +#else +static inline void debug_ll_io_init(void) {} +#endif + struct mem_type; extern const struct mem_type *get_mem_type(unsigned int type); /* diff --git a/arch/arm/kernel/debug.S b/arch/arm/kernel/debug.S index 66f711b..6809200 100644 --- a/arch/arm/kernel/debug.S +++ b/arch/arm/kernel/debug.S @@ -100,6 +100,13 @@ ENTRY(printch) b 1b ENDPROC(printch) +ENTRY(debug_ll_addr) + addruart r2, r3, ip + str r2, [r0] + str r3, [r1] + mov pc, lr +ENDPROC(debug_ll_addr) + #else ENTRY(printascii) @@ -119,4 +126,11 @@ ENTRY(printch) mov pc, lr ENDPROC(printch) +ENTRY(debug_ll_addr) + mov r2, #0 + str r2, [r0] + str r2, [r1] + mov pc, lr +ENDPROC(debug_ll_addr) + #endif diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c index 941dfb9..39719bb 100644 --- a/arch/arm/mm/mmu.c +++ b/arch/arm/mm/mmu.c @@ -876,6 +876,22 @@ static void __init pci_reserve_io(void) #define pci_reserve_io() do { } while (0) #endif +#ifdef CONFIG_DEBUG_LL +void __init debug_ll_io_init(void) +{ + struct map_desc map; + + debug_ll_addr(&map.pfn, &map.virtual); + if (!map.pfn || !map.virtual) + return; + map.pfn = __phys_to_pfn(map.pfn); + map.virtual &= PAGE_MASK; + map.length = PAGE_SIZE; + map.type = MT_DEVICE; + create_mapping(&map); +} +#endif + static void * __initdata vmalloc_min = (void *)(VMALLOC_END - (240 << 20) - VMALLOC_OFFSET); -- 1.7.0.4 -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
