/*
* Copyright (C) 2001-2006 Silicon Graphics, Inc. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of version 2 of the GNU General Public License
* as published by the Free Software Foundation.
*
* A simple uncached page allocator using the generic allocator. This
* allocator first utilizes the spare (spill) pages found in the EFI
* memmap and will then start converting cached pages to uncached ones
* at a granule at a time. Node awareness is implemented by having a
* pool of pages per node.
*/
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/efi.h>
#include <linux/genalloc.h>
#include <asm/page.h>
#include <asm/pal.h>
#include <asm/system.h>
#include <asm/pgtable.h>
#include <asm/atomic.h>
#include <asm/tlbflush.h>
#include <asm/sn/arch.h>
extern void __init efi_memmap_walk_uc(efi_freemem_callback_t, void *);
#define MAX_UNCACHED_GRANULES 5
static int allocated_granules;
struct gen_pool *uncached_pool[MAX_NUMNODES];
static void uncached_ipi_visibility(void *data)
{
int status;
status = ia64_pal_prefetch_visibility(PAL_VISIBILITY_PHYSICAL);
if ((status != PAL_VISIBILITY_OK) &&
(status != PAL_VISIBILITY_OK_REMOTE_NEEDED))
printk(KERN_DEBUG "pal_prefetch_visibility() returns %i on "
"CPU %i\n", status, raw_smp_processor_id());
}
static void uncached_ipi_mc_drain(void *data)
{
int status;
status = ia64_pal_mc_drain();
if (status)
printk(KERN_WARNING "ia64_pal_mc_drain() failed with %i on "
"CPU %i\n", status, raw_smp_processor_id());
}
/*
* Add a new chunk of uncached memory pages to the specified pool.
*
* @pool: pool to add new chunk of uncached memory to
* @nid: node id of node to allocate memory from, or -1
*
* This is accomplished by first allocating a granule of cached memory pages
* and then converting them to uncached memory pages.
*/
static int uncached_add_chunk(struct gen_pool *pool, int nid)
{
struct page *page;
int status, i;
unsigned long c_addr, uc_addr;
if (allocated_granules >= MAX_UNCACHED_GRANULES)
return -1;
/* attempt to allocate a granule's worth of cached memory pages */
page = alloc_pages_node(nid, GFP_KERNEL | __GFP_ZERO,
IA64_GRANULE_SHIFT-PAGE_SHIFT);
if (!page)
return -1;
/* convert the memory pages from cached to uncached */
c_addr = (unsigned long)page_address(page);
uc_addr = c_addr - PAGE_OFFSET + __IA64_UNCACHED_OFFSET;
/*
* There's a small race here where it's possible for someone to
* access the page through /dev/mem halfway through the conversion
* to uncached - not sure it's really worth bothering about
*/
for (i = 0; i < (IA64_GRANULE_SIZE / PAGE_SIZE); i++)
SetPageUncached(&page[i]);
flush_tlb_kernel_range(uc_addr, uc_adddr + IA64_GRANULE_SIZE);
status = ia64_pal_prefetch_visibility(PAL_VISIBILITY_PHYSICAL);
if (!status) {
status = smp_call_function(uncached_ipi_visibility, NULL, 0, 1);
if (status)
goto failed;
}
preempt_disable();
if (ia64_platform_is("sn2"))
sn_flush_all_caches(uc_addr, IA64_GRANULE_SIZE);
else
flush_icache_range(uc_addr, uc_addr + IA64_GRANULE_SIZE);
/* flush the just introduced uncached translation from the TLB */
local_flush_tlb_all();
preempt_enable();
ia64_pal_mc_drain();
status = smp_call_function(uncached_ipi_mc_drain, NULL, 0, 1);
if (status)
goto failed;
/*
* The chunk of memory pages has been converted to uncached so now we
* can add it to the pool.
*/
status = gen_pool_add(pool, uc_addr, IA64_GRANULE_SIZE, nid);
if (status)
goto failed;
allocated_granules++;
return 0;
/* failed to convert or add the chunk so give it back to the kernel */
failed:
for (i = 0; i < (IA64_GRANULE_SIZE / PAGE_SIZE); i++)
ClearPageUncached(&page[i]);
free_pages(c_addr, IA64_GRANULE_SHIFT-PAGE_SHIFT);
return -1;
}
/*
* uncached_alloc_page
*
* @starting_nid: node id of node to start with, or -1
*
* Allocate 1 uncached page. Allocates on the requested node. If no
* uncached pages are available on the requested node, roundrobin starting
* with the next higher node.
*/
unsigned long uncached_alloc_page(int starting_nid)
{
unsigned long uc_addr;
struct gen_pool *pool;
int nid;
if (unlikely(starting_nid >= MAX_NUMNODES))
return 0;
if (starting_nid < 0)
starting_nid = numa_node_id();
nid = starting_nid;
do {
if (!node_online(nid))
continue;
pool = uncached_pool[nid];
if (pool == NULL)
continue;
do {
uc_addr = gen_pool_alloc(pool, PAGE_SIZE);
if (uc_addr != 0)
return uc_addr;
} while (uncached_add_chunk(pool, nid) == 0);
} while ((nid = (nid + 1) % MAX_NUMNODES) != starting_nid);
return 0;
}
EXPORT_SYMBOL(uncached_alloc_page);
/*
* uncached_free_page
*
* @uc_addr: uncached address of page to free
*
* Free a single uncached page.
*/
void uncached_free_page(unsigned long uc_addr)
{
int nid = paddr_to_nid(uc_addr - __IA64_UNCACHED_OFFSET);
struct gen_pool *pool = uncached_pool[nid];
if (unlikely(pool == NULL))
return;
if ((uc_addr & (0XFUL << 60)) != __IA64_UNCACHED_OFFSET)
panic("uncached_free_page invalid address %lx\n", uc_addr);
gen_pool_free(pool, uc_addr, PAGE_SIZE);
}
EXPORT_SYMBOL(uncached_free_page);
/*
* uncached_build_memmap,
*
* @uc_start: uncached starting address of a chunk of uncached memory
* @uc_end: uncached ending address of a chunk of uncached memory
* @arg: ignored, (NULL argument passed in on call to efi_memmap_walk_uc())
*
* Called at boot time to build a map of pages that can be used for
* memory special operations.
*/
static int __init uncached_build_memmap(unsigned long uc_start,
unsigned long uc_end, void *arg)
{
int nid = paddr_to_nid(uc_start - __IA64_UNCACHED_OFFSET);
struct gen_pool *pool = uncached_pool[nid];
size_t size = uc_end - uc_start;
touch_softlockup_watchdog();
if (pool != NULL) {
memset((char *)uc_start, 0, size);
(void) gen_pool_add(pool, uc_start, size, nid);
}
return 0;
}
static int __init uncached_init(void)
{
int nid;
for_each_online_node(nid) {
uncached_pool[nid] = gen_pool_create(PAGE_SHIFT, nid);
}
efi_memmap_walk_uc(uncached_build_memmap, NULL);
return 0;
}
__initcall(uncached_init);
