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docs: xtensa: convert to ReST

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Rename the xtensa documentation files to ReST, add an
index for them and adjust in order to produce a nice html
output via the Sphinx build system.

At its new index.rst, let's add a :orphan: while this is not linked to
the main index.rst file, in order to avoid build warnings.

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
This commit is contained in:
Mauro Carvalho Chehab 2019-04-18 14:34:34 -03:00
parent b0a4aa950c
commit 8ea0afa3b8
6 changed files with 222 additions and 194 deletions
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13
Documentation/xtensa/atomctl.txt → Documentation/xtensa/atomctl.rst
View File

@ -1,3 +1,7 @@
===========================================
Atomic Operation Control (ATOMCTL) Register
===========================================
We Have Atomic Operation Control (ATOMCTL) Register.
This register determines the effect of using a S32C1I instruction
with various combinations of:
@ -8,7 +12,7 @@ with various combinations of:
2. With and without An Intelligent Memory Controller which
can do Atomic Transactions itself.
The Core comes up with a default value of for the three types of cache ops:
The Core comes up with a default value of for the three types of cache ops::
0x28: (WB: Internal, WT: Internal, BY:Exception)
@ -30,15 +34,18 @@ CUSTOMER-WARNING:
Developers might find using RCW in Bypass mode convenient when testing
with the cache being bypassed; for example studying cache alias problems.
See Section 4.3.12.4 of ISA; Bits:
See Section 4.3.12.4 of ISA; Bits::
WB WT BY
5 4 | 3 2 | 1 0
========= ================== ================== ===============
2 Bit
Field
Values WB - Write Back WT - Write Thru BY - Bypass
--------- --------------- ----------------- ----------------
========= ================== ================== ===============
0 Exception Exception Exception
1 RCW Transaction RCW Transaction RCW Transaction
2 Internal Operation Internal Operation Reserved
3 Reserved Reserved Reserved
========= ================== ================== ===============

5
Documentation/xtensa/booting.txt → Documentation/xtensa/booting.rst
View File

@ -1,10 +1,13 @@
Passing boot parameters to the kernel.
=====================================
Passing boot parameters to the kernel
=====================================
Boot parameters are represented as a TLV list in the memory. Please see
arch/xtensa/include/asm/bootparam.h for definition of the bp_tag structure and
tag value constants. First entry in the list must have type BP_TAG_FIRST, last
entry must have type BP_TAG_LAST. The address of the first list entry is
passed to the kernel in the register a2. The address type depends on MMU type:
- For configurations without MMU, with region protection or with MPU the
address must be the physical address.
- For configurations with region translarion MMU or with MMUv3 and CONFIG_MMU=n

12
Documentation/xtensa/index.rst Normal file
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@ -0,0 +1,12 @@
:orphan:
===================
Xtensa Architecture
===================
.. toctree::
:maxdepth: 1
atomctl
booting
mmu

195
Documentation/xtensa/mmu.rst Normal file
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@ -0,0 +1,195 @@
=============================
MMUv3 initialization sequence
=============================
The code in the initialize_mmu macro sets up MMUv3 memory mapping
identically to MMUv2 fixed memory mapping. Depending on
CONFIG_INITIALIZE_XTENSA_MMU_INSIDE_VMLINUX symbol this code is
located in addresses it was linked for (symbol undefined), or not
(symbol defined), so it needs to be position-independent.
The code has the following assumptions:
- This code fragment is run only on an MMU v3.
- TLBs are in their reset state.
- ITLBCFG and DTLBCFG are zero (reset state).
- RASID is 0x04030201 (reset state).
- PS.RING is zero (reset state).
- LITBASE is zero (reset state, PC-relative literals); required to be PIC.
TLB setup proceeds along the following steps.
Legend:
- VA = virtual address (two upper nibbles of it);
- PA = physical address (two upper nibbles of it);
- pc = physical range that contains this code;
After step 2, we jump to virtual address in the range 0x40000000..0x5fffffff
or 0x00000000..0x1fffffff, depending on whether the kernel was loaded below
0x40000000 or above. That address corresponds to next instruction to execute
in this code. After step 4, we jump to intended (linked) address of this code.
The scheme below assumes that the kernel is loaded below 0x40000000.
====== ===== ===== ===== ===== ====== ===== =====
- Step0 Step1 Step2 Step3 Step4 Step5
VA PA PA PA PA VA PA PA
====== ===== ===== ===== ===== ====== ===== =====
E0..FF -> E0 -> E0 -> E0 F0..FF -> F0 -> F0
C0..DF -> C0 -> C0 -> C0 E0..EF -> F0 -> F0
A0..BF -> A0 -> A0 -> A0 D8..DF -> 00 -> 00
80..9F -> 80 -> 80 -> 80 D0..D7 -> 00 -> 00
60..7F -> 60 -> 60 -> 60
40..5F -> 40 -> pc -> pc 40..5F -> pc
20..3F -> 20 -> 20 -> 20
00..1F -> 00 -> 00 -> 00
====== ===== ===== ===== ===== ====== ===== =====
The default location of IO peripherals is above 0xf0000000. This may be changed
using a "ranges" property in a device tree simple-bus node. See the Devicetree
Specification, section 4.5 for details on the syntax and semantics 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
MMUv3 address space layouts.
============================
Default MMUv2-compatible layout::
Symbol VADDR Size
+------------------+
| Userspace | 0x00000000 TASK_SIZE
+------------------+ 0x40000000
+------------------+
| Page table | XCHAL_PAGE_TABLE_VADDR 0x80000000 XCHAL_PAGE_TABLE_SIZE
+------------------+
| KASAN shadow map | KASAN_SHADOW_START 0x80400000 KASAN_SHADOW_SIZE
+------------------+ 0x8e400000
+------------------+
| VMALLOC area | VMALLOC_START 0xc0000000 128MB - 64KB
+------------------+ VMALLOC_END
| Cache aliasing | TLBTEMP_BASE_1 0xc7ff0000 DCACHE_WAY_SIZE
| remap area 1 |
+------------------+
| Cache aliasing | TLBTEMP_BASE_2 DCACHE_WAY_SIZE
| remap area 2 |
+------------------+
+------------------+
| KMAP area | PKMAP_BASE PTRS_PER_PTE *
| | DCACHE_N_COLORS *
| | PAGE_SIZE
| | (4MB * DCACHE_N_COLORS)
+------------------+
| Atomic KMAP area | FIXADDR_START KM_TYPE_NR *
| | NR_CPUS *
| | DCACHE_N_COLORS *
| | PAGE_SIZE
+------------------+ FIXADDR_TOP 0xcffff000
+------------------+
| Cached KSEG | XCHAL_KSEG_CACHED_VADDR 0xd0000000 128MB
+------------------+
| Uncached KSEG | XCHAL_KSEG_BYPASS_VADDR 0xd8000000 128MB
+------------------+
| Cached KIO | XCHAL_KIO_CACHED_VADDR 0xe0000000 256MB
+------------------+
| Uncached KIO | XCHAL_KIO_BYPASS_VADDR 0xf0000000 256MB
+------------------+
256MB cached + 256MB uncached layout::
Symbol VADDR Size
+------------------+
| Userspace | 0x00000000 TASK_SIZE
+------------------+ 0x40000000
+------------------+
| Page table | XCHAL_PAGE_TABLE_VADDR 0x80000000 XCHAL_PAGE_TABLE_SIZE
+------------------+
| KASAN shadow map | KASAN_SHADOW_START 0x80400000 KASAN_SHADOW_SIZE
+------------------+ 0x8e400000
+------------------+
| VMALLOC area | VMALLOC_START 0xa0000000 128MB - 64KB
+------------------+ VMALLOC_END
| Cache aliasing | TLBTEMP_BASE_1 0xa7ff0000 DCACHE_WAY_SIZE
| remap area 1 |
+------------------+
| Cache aliasing | TLBTEMP_BASE_2 DCACHE_WAY_SIZE
| remap area 2 |
+------------------+
+------------------+
| KMAP area | PKMAP_BASE PTRS_PER_PTE *
| | DCACHE_N_COLORS *
| | PAGE_SIZE
| | (4MB * DCACHE_N_COLORS)
+------------------+
| Atomic KMAP area | FIXADDR_START KM_TYPE_NR *
| | NR_CPUS *
| | DCACHE_N_COLORS *
| | PAGE_SIZE
+------------------+ FIXADDR_TOP 0xaffff000
+------------------+
| Cached KSEG | XCHAL_KSEG_CACHED_VADDR 0xb0000000 256MB
+------------------+
| Uncached KSEG | XCHAL_KSEG_BYPASS_VADDR 0xc0000000 256MB
+------------------+
+------------------+
| Cached KIO | XCHAL_KIO_CACHED_VADDR 0xe0000000 256MB
+------------------+
| Uncached KIO | XCHAL_KIO_BYPASS_VADDR 0xf0000000 256MB
+------------------+
512MB cached + 512MB uncached layout::
Symbol VADDR Size
+------------------+
| Userspace | 0x00000000 TASK_SIZE
+------------------+ 0x40000000
+------------------+
| Page table | XCHAL_PAGE_TABLE_VADDR 0x80000000 XCHAL_PAGE_TABLE_SIZE
+------------------+
| KASAN shadow map | KASAN_SHADOW_START 0x80400000 KASAN_SHADOW_SIZE
+------------------+ 0x8e400000
+------------------+
| VMALLOC area | VMALLOC_START 0x90000000 128MB - 64KB
+------------------+ VMALLOC_END
| Cache aliasing | TLBTEMP_BASE_1 0x97ff0000 DCACHE_WAY_SIZE
| remap area 1 |
+------------------+
| Cache aliasing | TLBTEMP_BASE_2 DCACHE_WAY_SIZE
| remap area 2 |
+------------------+
+------------------+
| KMAP area | PKMAP_BASE PTRS_PER_PTE *
| | DCACHE_N_COLORS *
| | PAGE_SIZE
| | (4MB * DCACHE_N_COLORS)
+------------------+
| Atomic KMAP area | FIXADDR_START KM_TYPE_NR *
| | NR_CPUS *
| | DCACHE_N_COLORS *
| | PAGE_SIZE
+------------------+ FIXADDR_TOP 0x9ffff000
+------------------+
| Cached KSEG | XCHAL_KSEG_CACHED_VADDR 0xa0000000 512MB
+------------------+
| Uncached KSEG | XCHAL_KSEG_BYPASS_VADDR 0xc0000000 512MB
+------------------+
| Cached KIO | XCHAL_KIO_CACHED_VADDR 0xe0000000 256MB
+------------------+
| Uncached KIO | XCHAL_KIO_BYPASS_VADDR 0xf0000000 256MB
+------------------+

189
Documentation/xtensa/mmu.txt
View File

@ -1,189 +0,0 @@
MMUv3 initialization sequence.
The code in the initialize_mmu macro sets up MMUv3 memory mapping
identically to MMUv2 fixed memory mapping. Depending on
CONFIG_INITIALIZE_XTENSA_MMU_INSIDE_VMLINUX symbol this code is
located in addresses it was linked for (symbol undefined), or not
(symbol defined), so it needs to be position-independent.
The code has the following assumptions:
This code fragment is run only on an MMU v3.
TLBs are in their reset state.
ITLBCFG and DTLBCFG are zero (reset state).
RASID is 0x04030201 (reset state).
PS.RING is zero (reset state).
LITBASE is zero (reset state, PC-relative literals); required to be PIC.
TLB setup proceeds along the following steps.
Legend:
VA = virtual address (two upper nibbles of it);
PA = physical address (two upper nibbles of it);
pc = physical range that contains this code;
After step 2, we jump to virtual address in the range 0x40000000..0x5fffffff
or 0x00000000..0x1fffffff, depending on whether the kernel was loaded below
0x40000000 or above. That address corresponds to next instruction to execute
in this code. After step 4, we jump to intended (linked) address of this code.
The scheme below assumes that the kernel is loaded below 0x40000000.
Step0 Step1 Step2 Step3 Step4 Step5
===== ===== ===== ===== ===== =====
VA PA PA PA PA VA PA PA
------ -- -- -- -- ------ -- --
E0..FF -> E0 -> E0 -> E0 F0..FF -> F0 -> F0
C0..DF -> C0 -> C0 -> C0 E0..EF -> F0 -> F0
A0..BF -> A0 -> A0 -> A0 D8..DF -> 00 -> 00
80..9F -> 80 -> 80 -> 80 D0..D7 -> 00 -> 00
60..7F -> 60 -> 60 -> 60
40..5F -> 40 -> pc -> pc 40..5F -> pc
20..3F -> 20 -> 20 -> 20
00..1F -> 00 -> 00 -> 00
The default location of IO peripherals is above 0xf0000000. This may be changed
using a "ranges" property in a device tree simple-bus node. See the Devicetree
Specification, section 4.5 for details on the syntax and semantics 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
MMUv3 address space layouts.
============================
Default MMUv2-compatible layout.
Symbol VADDR Size
+------------------+
| Userspace | 0x00000000 TASK_SIZE
+------------------+ 0x40000000
+------------------+
| Page table | XCHAL_PAGE_TABLE_VADDR 0x80000000 XCHAL_PAGE_TABLE_SIZE
+------------------+
| KASAN shadow map | KASAN_SHADOW_START 0x80400000 KASAN_SHADOW_SIZE
+------------------+ 0x8e400000
+------------------+
| VMALLOC area | VMALLOC_START 0xc0000000 128MB - 64KB
+------------------+ VMALLOC_END
| Cache aliasing | TLBTEMP_BASE_1 0xc7ff0000 DCACHE_WAY_SIZE
| remap area 1 |
+------------------+
| Cache aliasing | TLBTEMP_BASE_2 DCACHE_WAY_SIZE
| remap area 2 |
+------------------+
+------------------+
| KMAP area | PKMAP_BASE PTRS_PER_PTE *
| | DCACHE_N_COLORS *
| | PAGE_SIZE
| | (4MB * DCACHE_N_COLORS)
+------------------+
| Atomic KMAP area | FIXADDR_START KM_TYPE_NR *
| | NR_CPUS *
| | DCACHE_N_COLORS *
| | PAGE_SIZE
+------------------+ FIXADDR_TOP 0xcffff000
+------------------+
| Cached KSEG | XCHAL_KSEG_CACHED_VADDR 0xd0000000 128MB
+------------------+
| Uncached KSEG | XCHAL_KSEG_BYPASS_VADDR 0xd8000000 128MB
+------------------+
| Cached KIO | XCHAL_KIO_CACHED_VADDR 0xe0000000 256MB
+------------------+
| Uncached KIO | XCHAL_KIO_BYPASS_VADDR 0xf0000000 256MB
+------------------+
256MB cached + 256MB uncached layout.
Symbol VADDR Size
+------------------+
| Userspace | 0x00000000 TASK_SIZE
+------------------+ 0x40000000
+------------------+
| Page table | XCHAL_PAGE_TABLE_VADDR 0x80000000 XCHAL_PAGE_TABLE_SIZE
+------------------+
| KASAN shadow map | KASAN_SHADOW_START 0x80400000 KASAN_SHADOW_SIZE
+------------------+ 0x8e400000
+------------------+
| VMALLOC area | VMALLOC_START 0xa0000000 128MB - 64KB
+------------------+ VMALLOC_END
| Cache aliasing | TLBTEMP_BASE_1 0xa7ff0000 DCACHE_WAY_SIZE
| remap area 1 |
+------------------+
| Cache aliasing | TLBTEMP_BASE_2 DCACHE_WAY_SIZE
| remap area 2 |
+------------------+
+------------------+
| KMAP area | PKMAP_BASE PTRS_PER_PTE *
| | DCACHE_N_COLORS *
| | PAGE_SIZE
| | (4MB * DCACHE_N_COLORS)
+------------------+
| Atomic KMAP area | FIXADDR_START KM_TYPE_NR *
| | NR_CPUS *
| | DCACHE_N_COLORS *
| | PAGE_SIZE
+------------------+ FIXADDR_TOP 0xaffff000
+------------------+
| Cached KSEG | XCHAL_KSEG_CACHED_VADDR 0xb0000000 256MB
+------------------+
| Uncached KSEG | XCHAL_KSEG_BYPASS_VADDR 0xc0000000 256MB
+------------------+
+------------------+
| Cached KIO | XCHAL_KIO_CACHED_VADDR 0xe0000000 256MB
+------------------+
| Uncached KIO | XCHAL_KIO_BYPASS_VADDR 0xf0000000 256MB
+------------------+
512MB cached + 512MB uncached layout.
Symbol VADDR Size
+------------------+
| Userspace | 0x00000000 TASK_SIZE
+------------------+ 0x40000000
+------------------+
| Page table | XCHAL_PAGE_TABLE_VADDR 0x80000000 XCHAL_PAGE_TABLE_SIZE
+------------------+
| KASAN shadow map | KASAN_SHADOW_START 0x80400000 KASAN_SHADOW_SIZE
+------------------+ 0x8e400000
+------------------+
| VMALLOC area | VMALLOC_START 0x90000000 128MB - 64KB
+------------------+ VMALLOC_END
| Cache aliasing | TLBTEMP_BASE_1 0x97ff0000 DCACHE_WAY_SIZE
| remap area 1 |
+------------------+
| Cache aliasing | TLBTEMP_BASE_2 DCACHE_WAY_SIZE
| remap area 2 |
+------------------+
+------------------+
| KMAP area | PKMAP_BASE PTRS_PER_PTE *
| | DCACHE_N_COLORS *
| | PAGE_SIZE
| | (4MB * DCACHE_N_COLORS)
+------------------+
| Atomic KMAP area | FIXADDR_START KM_TYPE_NR *
| | NR_CPUS *
| | DCACHE_N_COLORS *
| | PAGE_SIZE
+------------------+ FIXADDR_TOP 0x9ffff000
+------------------+
| Cached KSEG | XCHAL_KSEG_CACHED_VADDR 0xa0000000 512MB
+------------------+
| Uncached KSEG | XCHAL_KSEG_BYPASS_VADDR 0xc0000000 512MB
+------------------+
| Cached KIO | XCHAL_KIO_CACHED_VADDR 0xe0000000 256MB
+------------------+
| Uncached KIO | XCHAL_KIO_BYPASS_VADDR 0xf0000000 256MB
+------------------+

2
arch/xtensa/include/asm/initialize_mmu.h
View File

@ -42,7 +42,7 @@
#if XCHAL_HAVE_S32C1I && (XCHAL_HW_MIN_VERSION >= XTENSA_HWVERSION_RC_2009_0)
/*
* We Have Atomic Operation Control (ATOMCTL) Register; Initialize it.
* For details see Documentation/xtensa/atomctl.txt
* For details see Documentation/xtensa/atomctl.rst
*/
#if XCHAL_DCACHE_IS_COHERENT
movi a3, 0x25 /* For SMP/MX -- internal for writeback,