From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steffen Persvold Date: Mon, 10 Sep 2001 19:29:17 +0000 Subject: Re: [Linux-ia64] Re: Write Combining (Write Coalescing) on memory mapped MIME-Version: 1 Content-Type: multipart/mixed; boundary="------------928874364022458C7784A02F" Message-Id: List-Id: References: In-Reply-To: To: linux-ia64@vger.kernel.org This is a multi-part message in MIME format. --------------928874364022458C7784A02F Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit David Mosberger wrote: > > >>>>> On Mon, 10 Sep 2001 17:26:47 +0200, Steffen Persvold said: > > Steffen> This is what my original post (which included a patch) > Steffen> tried to do, but I didn't get it too work. I know you gave > Steffen> me feedback on this David, saying that it just may need > Steffen> some debugging. Does anyone on the list have the time to > Steffen> just look through the patch and try to analyze what's going > Steffen> wrong (or maybe just give me some hints on what to look > Steffen> for) ? > > I don't, not in the near future at least. > > There is nothing magical about debugging on ia64. Just use the normal > techniques: try to narrow down what's triggering the problem, e.g., > via binary search, printk, etc. A kdb patch is also available. > Yep, I know. But I managed to solve it without the use of kdb. It was just a question of using the right __pgprot flags. I've attached a new patch, it's made against 2.4.4 but it also applies cleanly to a vanilla 2.4.9 tree. I guess this means that we don't have to use the uncached region 6 anymore; ioremap() could be modified to use __ia64_ioremap() with the _PAGE_MA_WC attribute and ioremap_nocache() to with the _PAGE_MA_UC attribute. Any comments ? I sure hope that this is patch that you would consider going into the main ia64 tree. Regards, -- Steffen Persvold | Scali Computer AS | Try out the world's best mailto:sp@scali.no | http://www.scali.com | performing MPI implementation: Tel: (+47) 2262 8950 | Olaf Helsets vei 6 | - ScaMPI 1.12.2 - Fax: (+47) 2262 8951 | N0621 Oslo, NORWAY | >300MBytes/s and <4uS latency --------------928874364022458C7784A02F Content-Type: text/plain; charset=us-ascii; name="ia64-ioremap.patch" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="ia64-ioremap.patch" --- linux-2.4.4/arch/ia64/mm/Makefile.~1~ Thu Jan 4 21:50:17 2001 +++ linux-2.4.4/arch/ia64/mm/Makefile Sat Aug 11 21:20:03 2001 @@ -9,6 +9,6 @@ O_TARGET := mm.o -obj-y := init.o fault.o tlb.o extable.o +obj-y := init.o fault.o ioremap.o tlb.o extable.o include $(TOPDIR)/Rules.make --- linux-2.4.4/arch/ia64/mm/ioremap.c.~1~ Tue May 5 22:32:27 1998 +++ linux-2.4.4/arch/ia64/mm/ioremap.c Sat Aug 11 23:57:31 2001 @@ -0,0 +1,154 @@ +/* + * arch/s390/mm/ioremap.c + * + * IA64 version + * Copyright (C) 2001 Scali AS + * Author(s): Steffen Persvold (sp@scali.com) + * + * Derived from "arch/i386/mm/ioremap.c" + * (C) Copyright 1995 1996 Linus Torvalds + * + * Re-map IO memory to kernel address space so that we can access it. + */ + +#include +#include +#include + +static inline void remap_area_pte(pte_t * pte, unsigned long address, unsigned long size, + unsigned long phys_addr, unsigned long flags) +{ + unsigned long end; + + address &= ~PMD_MASK; + end = address + size; + if (end > PMD_SIZE) + end = PMD_SIZE; + if (address >= end) + BUG(); + do { + if (!pte_none(*pte)) { + printk("remap_area_pte: page already exists\n"); + BUG(); + } + set_pte(pte, mk_pte_phys(phys_addr, __pgprot(__DIRTY_BITS | _PAGE_PL_0 | + _PAGE_AR_RWX | (flags & _PAGE_MA_MASK)))); + address += PAGE_SIZE; + phys_addr += PAGE_SIZE; + pte++; + } while (address && (address < end)); +} + +static inline int remap_area_pmd(pmd_t * pmd, unsigned long address, unsigned long size, + unsigned long phys_addr, unsigned long flags) +{ + unsigned long end; + + address &= ~PGDIR_MASK; + end = address + size; + if (end > PGDIR_SIZE) + end = PGDIR_SIZE; + phys_addr -= address; + if (address >= end) + BUG(); + do { + pte_t * pte = pte_alloc(&init_mm, pmd, address); + if (!pte) + return -ENOMEM; + remap_area_pte(pte, address, end - address, address + phys_addr, flags); + address = (address + PMD_SIZE) & PMD_MASK; + pmd++; + } while (address && (address < end)); + return 0; +} + +static int remap_area_pages(unsigned long address, unsigned long phys_addr, + unsigned long size, unsigned long flags) +{ + int error; + pgd_t * dir; + unsigned long end = address + size; + + phys_addr -= address; + dir = pgd_offset_k(address); + flush_cache_all(); + if (address >= end) + BUG(); + spin_lock(&init_mm.page_table_lock); + do { + pmd_t *pmd; + pmd = pmd_alloc(&init_mm, dir, address); + error = -ENOMEM; + if (!pmd) + break; + if (remap_area_pmd(pmd, address, end - address, + phys_addr + address, flags)) + break; + error = 0; + address = (address + PGDIR_SIZE) & PGDIR_MASK; + dir++; + } while (address && (address < end)); + spin_unlock(&init_mm.page_table_lock); + flush_tlb_all(); + return error; +} + +/* + * Generic mapping function (not visible outside): + */ + +/* + * Remap an arbitrary physical address space into the kernel virtual + * address space. Needed when the kernel wants to access high addresses + * directly. + * + * NOTE! We need to allow non-page-aligned mappings too: we will obviously + * have to convert them into an offset in a page-aligned mapping, but the + * caller shouldn't need to know that small detail. + */ +void * __ia64_ioremap(unsigned long phys_addr, unsigned long size, unsigned long flags) +{ + void * addr; + struct vm_struct * area; + unsigned long offset, last_addr; + + /* Don't allow wraparound or zero size */ + last_addr = phys_addr + size - 1; + if (!size || last_addr < phys_addr) + return NULL; + + /* + * Don't allow anybody to remap normal RAM that we're using.. + */ + if (phys_addr < virt_to_phys(high_memory)) + return NULL; + + /* + * Mappings have to be page-aligned + */ + offset = phys_addr & ~PAGE_MASK; + phys_addr &= PAGE_MASK; + size = PAGE_ALIGN(last_addr) - phys_addr; + + /* + * Ok, go for it.. + */ + area = get_vm_area(size, VM_IOREMAP); + if (!area) + return NULL; + addr = area->addr; + + if ((flags & _PAGE_MA_MASK) == 0) + flags = _PAGE_MA_UC; + + if (remap_area_pages(VMALLOC_VMADDR(addr), phys_addr, size, flags)) { + vfree(addr); + return NULL; + } + return (void *) (offset + (char *)addr); +} + +void __ia64_iounmap(void *addr) +{ + return vfree(addr); +} --- linux-2.4.4/arch/ia64/kernel/ia64_ksyms.c.~1~ Thu Apr 5 21:51:47 2001 +++ linux-2.4.4/arch/ia64/kernel/ia64_ksyms.c Sat Aug 11 23:57:12 2001 @@ -39,6 +39,8 @@ EXPORT_SYMBOL(ip_fast_csum); #include +EXPORT_SYMBOL(__ia64_ioremap); +EXPORT_SYMBOL(__ia64_iounmap); EXPORT_SYMBOL(__ia64_memcpy_fromio); EXPORT_SYMBOL(__ia64_memcpy_toio); EXPORT_SYMBOL(__ia64_memset_c_io); --- linux-2.4.4/include/asm-ia64/io.h.~1~ Thu Apr 5 21:51:47 2001 +++ linux-2.4.4/include/asm-ia64/io.h Sat Aug 11 23:59:36 2001 @@ -386,6 +386,9 @@ #define ioremap_nocache(o,s) ioremap(o,s) +extern void * __ia64_ioremap(unsigned long offset, unsigned long size, unsigned long flags); +extern void __ia64_iounmap(void *addr); + # ifdef __KERNEL__ /* --------------928874364022458C7784A02F--