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xtensa: remap io area defined in device tree

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Use the simple-bus node to discover the io area, and remap the cached and
bypass io ranges. The parent-bus-address value of the first triplet in the
"ranges" property is used. This value is rounded down to the nearest 256MB
boundary. The length of the io area is fixed at 256MB; the "ranges" property
length value is ignored.

Other limitations: (1) only the first simple-bus node is considered, and (2)
only the first triplet of the "ranges" property is considered.

See ePAPR 1.1 §6.5 for the simple-bus node description, and §2.3.8 for the
"ranges" property description.

Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
This commit is contained in:
Baruch Siach 2013-12-29 11:03:30 +02:00 committed by Max Filippov
parent f8935f307f
commit 6cb971114f
6 changed files with 93 additions and 5 deletions
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18
Documentation/xtensa/mmu.txt
View file

@ -44,3 +44,21 @@ After step 4, we jump to intended (linked) address of this code.
40..5F -> 40 40..5F -> pc -> pc 40..5F -> pc
20..3F -> 20 -> 20 20..3F -> 20
00..1F -> 00 -> 00 00..1F -> 00
The default location of IO peripherals is above 0xf0000000. This may change
using a "ranges" property in a device tree simple-bus node. See ePAPR 1.1, §6.5
for details on the syntax and semantic of simple-bus nodes. The following
limitations apply:
1. Only top level simple-bus nodes are considered
2. Only one (first) simple-bus node is considered
3. Empty "ranges" properties are not supported
4. Only the first triplet in the "ranges" property is considered
5. The parent-bus-address value is rounded down to the nearest 256MB boundary
6. The IO area covers the entire 256MB segment of parent-bus-address; the
"ranges" triplet length field is ignored

9
arch/xtensa/include/asm/initialize_mmu.h
View file

@ -26,6 +26,9 @@
#include <asm/pgtable.h>
#include <asm/vectors.h>
#define CA_BYPASS (_PAGE_CA_BYPASS | _PAGE_HW_WRITE | _PAGE_HW_EXEC)
#define CA_WRITEBACK (_PAGE_CA_WB | _PAGE_HW_WRITE | _PAGE_HW_EXEC)
#ifdef __ASSEMBLY__
#define XTENSA_HWVERSION_RC_2009_0 230000
@ -80,8 +83,6 @@
/* Step 2: map 0x40000000..0x47FFFFFF to paddr containing this code
* and jump to the new mapping.
*/
#define CA_BYPASS (_PAGE_CA_BYPASS | _PAGE_HW_WRITE | _PAGE_HW_EXEC)
#define CA_WRITEBACK (_PAGE_CA_WB | _PAGE_HW_WRITE | _PAGE_HW_EXEC)
srli a3, a0, 27
slli a3, a3, 27
@ -124,12 +125,12 @@
witlb a4, a5
movi a5, XCHAL_KIO_CACHED_VADDR + 6
movi a4, XCHAL_KIO_PADDR + CA_WRITEBACK
movi a4, XCHAL_KIO_DEFAULT_PADDR + CA_WRITEBACK
wdtlb a4, a5
witlb a4, a5
movi a5, XCHAL_KIO_BYPASS_VADDR + 6
movi a4, XCHAL_KIO_PADDR + CA_BYPASS
movi a4, XCHAL_KIO_DEFAULT_PADDR + CA_BYPASS
wdtlb a4, a5
witlb a4, a5

10
arch/xtensa/include/asm/io.h
View file

@ -24,6 +24,16 @@
#define IO_SPACE_LIMIT ~0
#ifdef CONFIG_MMU
#if XCHAL_HAVE_PTP_MMU && XCHAL_HAVE_SPANNING_WAY && CONFIG_OF
extern unsigned long xtensa_kio_paddr;
static inline unsigned long xtensa_get_kio_paddr(void)
{
return xtensa_kio_paddr;
}
#endif
/*
* Return the virtual address for the specified bus memory.
* Note that we currently don't support any address outside the KIO segment.

8
arch/xtensa/include/asm/vectors.h
View file

@ -22,9 +22,15 @@
#define XCHAL_KIO_CACHED_VADDR 0xe0000000
#define XCHAL_KIO_BYPASS_VADDR 0xf0000000
#define XCHAL_KIO_PADDR 0xf0000000
#define XCHAL_KIO_DEFAULT_PADDR 0xf0000000
#define XCHAL_KIO_SIZE 0x10000000
#if XCHAL_HAVE_PTP_MMU && XCHAL_HAVE_SPANNING_WAY && CONFIG_OF
#define XCHAL_KIO_PADDR xtensa_get_kio_paddr()
#else
#define XCHAL_KIO_PADDR XCHAL_KIO_DEFAULT_PADDR
#endif
#if defined(CONFIG_MMU)
/* Will Become VECBASE */

37
arch/xtensa/kernel/setup.c
View file

@ -212,6 +212,42 @@ static int __init parse_bootparam(const bp_tag_t* tag)
#ifdef CONFIG_OF
bool __initdata dt_memory_scan = false;
#if XCHAL_HAVE_PTP_MMU && XCHAL_HAVE_SPANNING_WAY
unsigned long xtensa_kio_paddr = XCHAL_KIO_DEFAULT_PADDR;
EXPORT_SYMBOL(xtensa_kio_paddr);
static int __init xtensa_dt_io_area(unsigned long node, const char *uname,
int depth, void *data)
{
const __be32 *ranges;
unsigned long len;
if (depth > 1)
return 0;
if (!of_flat_dt_is_compatible(node, "simple-bus"))
return 0;
ranges = of_get_flat_dt_prop(node, "ranges", &len);
if (!ranges)
return 1;
if (len == 0)
return 1;
xtensa_kio_paddr = of_read_ulong(ranges+1, 1);
/* round down to nearest 256MB boundary */
xtensa_kio_paddr &= 0xf0000000;
return 1;
}
#else
static int __init xtensa_dt_io_area(unsigned long node, const char *uname,
int depth, void *data)
{
return 1;
}
#endif
void __init early_init_dt_add_memory_arch(u64 base, u64 size)
{
if (!dt_memory_scan)
@ -232,6 +268,7 @@ void __init early_init_devtree(void *params)
dt_memory_scan = true;
early_init_dt_scan(params);
of_scan_flat_dt(xtensa_dt_io_area, NULL);
if (!command_line[0])
strlcpy(command_line, boot_command_line, COMMAND_LINE_SIZE);

16
arch/xtensa/mm/mmu.c
View file

@ -13,6 +13,8 @@
#include <asm/tlbflush.h>
#include <asm/mmu_context.h>
#include <asm/page.h>
#include <asm/initialize_mmu.h>
#include <asm/io.h>
void __init paging_init(void)
{
@ -37,6 +39,20 @@ void init_mmu(void)
set_itlbcfg_register(0);
set_dtlbcfg_register(0);
#endif
#if XCHAL_HAVE_PTP_MMU && XCHAL_HAVE_SPANNING_WAY && CONFIG_OF
/*
* Update the IO area mapping in case xtensa_kio_paddr has changed
*/
write_dtlb_entry(__pte(xtensa_kio_paddr + CA_WRITEBACK),
XCHAL_KIO_CACHED_VADDR + 6);
write_itlb_entry(__pte(xtensa_kio_paddr + CA_WRITEBACK),
XCHAL_KIO_CACHED_VADDR + 6);
write_dtlb_entry(__pte(xtensa_kio_paddr + CA_BYPASS),
XCHAL_KIO_BYPASS_VADDR + 6);
write_itlb_entry(__pte(xtensa_kio_paddr + CA_BYPASS),
XCHAL_KIO_BYPASS_VADDR + 6);
#endif
local_flush_tlb_all();
/* Set rasid register to a known value. */