NDMA Registers: Difference between revisions

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3DS NDMA has 8 channels. The first 0x100-bytes of this IO mem is mirrored at 0x10002100, repeated every 0x100-bytes until the end of the 0x1000-byte IO mem. NDMA can access the ARM9 bootrom, including the protected part before it is locked out.
3DS NDMA has 8 channels. The first 0x100-bytes of this IO mem is mirrored at 0x10002100, repeated every 0x100-bytes until the end of the 0x1000-byte IO mem. NDMA can access the Arm9 bootrom, including the protected part before it is locked out.


= Registers =
= Registers =
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!  Bit
!  Bit
!  Description
!  Description
|-
|  4-0
|  Device to device startup mode
|-
|-
|  11-10
|  11-10
Line 168: Line 171:
|}
|}


== Startup modes (27-24) ==
== Startup modes (4-0) ==
{| class="wikitable" border="1"
{| class="wikitable" border="1"
!  Value
!  Value
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|-
|-
| 6
| 6
| MMC1
| SDIO1
|-
|-
| 7
| 7
| MMC2?
| SDIO3
|-
|-
| 8
| 8
Line 207: Line 210:
|-
|-
| 11
| 11
| SHA out ([[SHA_Registers#SHA_FIFO|INFIFO]])
| SHA out ([[SHA_Registers#SHA_FIFO|INFIFO]], source data readback mode)
|-
|-
| 12
| 12
| ?
| NTRCARD
|-
|-
| 13
| 13
Line 219: Line 222:
|-
|-
| 15
| 15
| Boot9 Uses this to copy from the AES out FIFO to the SHA in FIFO
| Device to device (subclassed by bits 4-0)
|}
 
== Device to device startup modes (4-0) ==
{| class="wikitable" border="1"
!  Value
!  Description
|-
| 0
| CTRCARD0 -> AES
|-
| 1
| CTRCARD1 -> AES
|-
| 2
| AES -> CTRCARD0
|-
| 3
| AES -> CTRCARD1
|-
| 4
| CTRCARD0 -> SHA
|-
| 5
| CTRCARD1 -> SHA
|-
| 6
| SHA -> CTRCARD0
|-
| 7
| SHA -> CTRCARD1
|-
| 8
| SDIO1 -> AES
|-
| 9
| SDIO3 -> AES
|-
| 10
| AES -> SDIO1
|-
| 11
| AES -> SDIO3
|-
| 12
| SDIO1 -> SHA
|-
| 13
| SDIO3 -> SHA
|-
| 14
| SHA -> SDIO1
|-
| 15
| SHA -> SDIO3
|-
| 16
| AES -> SHA
|-
| 17
| SHA -> AES
|}
|}


Latest revision as of 23:48, 10 November 2021

3DS NDMA has 8 channels. The first 0x100-bytes of this IO mem is mirrored at 0x10002100, repeated every 0x100-bytes until the end of the 0x1000-byte IO mem. NDMA can access the Arm9 bootrom, including the protected part before it is locked out.

Registers

Old3DS Name Address Width Used by
Yes NDMA_GLOBAL_CNT 0x10002000 4 Boot9, Kernel9
Yes NDMA_SRC_ADDR(n) 0x10002004 + (n*0x1c) 4 Boot9, Kernel9
Yes NDMA_DST_ADDR(n) 0x10002008 + (n*0x1c) 4 Boot9, Kernel9
Yes NDMA_TRANSFER_CNT(n) 0x1000200c + (n*0x1c) 4 Boot9, Kernel9
Yes NDMA_WRITE_CNT(n) 0x10002010 + (n*0x1c) 4 Boot9, Kernel9
Yes NDMA_BLOCK_CNT(n) 0x10002014 + (n*0x1c) 4 Boot9, Kernel9
Yes NDMA_FILL_DATA(n) 0x10002018 + (n*0x1c) 4 Boot9, Kernel9
Yes NDMA_CNT(n) 0x1000201C + (n*0x1c) 4 Boot9, Kernel9

NDMA_GLOBAL_CNT

Bit Description
0 Global enable?
19-16 Cycle selection.
31 DMA arbitration method. 0=Fixed method, 1=Round robin

NDMA_SRC_ADDR

Bit Description
31-0 Source data address. Must be multiple of 4.

Like old DMA, NDMA_SRC_ADDR is copied to internal registers when written to.

NDMA_DST_ADDR

BIT DESCRIPTION
31-0 Destination data address. Must be multiple of 4.

Like old DMA, NDMA_DST_ADDR is copied to internal registers when written to.

NDMA_TRANSFER_CNT

Bit Description
27-0 Total number of words transferred.

NDMA_WRITE_CNT

Bit Description
23-0 Number of words to transfer.

NDMA_BLOCK_CNT

Bit Description
15-0 Interval timer.
17-16 Prescaler. 0=System freq, 1=1/4th freq, 2=1/16th freq, 3=1/64th freq.

NDMA_FILL_DATA

Bit Description
31-0 Fill data.

NDMA_CNT

Bit Description
4-0 Device to device startup mode
11-10 Destination address update method. 0=Increment, 1=Decrement, 2=Fixed.
12 Destination address reload flag.
14-13 Source address update method. 0=Increment, 1=Decrement, 2=Fixed, 3=No address (for filling)
15 Source address reload flag.
19-16 Block transfer word count = (1<<x) words.
27-24 Startup mode.
28 Immediate mode.
29 Repeating mode.
30 IRQ enable
31 Enable/busy flag.

Startup modes (4-0)

Value Description
0 TIMER0
1 TIMER1
2 TIMER2
3 TIMER3
4 CTRCARD0
5 CTRCARD1
6 SDIO1
7 SDIO3
8 AES in (WRFIFO)
9 AES out (RDFIFO)
10 SHA in (INFIFO)
11 SHA out (INFIFO, source data readback mode)
12 NTRCARD
13 ?
14 ?
15 Device to device (subclassed by bits 4-0)

Device to device startup modes (4-0)

Value Description
0 CTRCARD0 -> AES
1 CTRCARD1 -> AES
2 AES -> CTRCARD0
3 AES -> CTRCARD1
4 CTRCARD0 -> SHA
5 CTRCARD1 -> SHA
6 SHA -> CTRCARD0
7 SHA -> CTRCARD1
8 SDIO1 -> AES
9 SDIO3 -> AES
10 AES -> SDIO1
11 AES -> SDIO3
12 SDIO1 -> SHA
13 SDIO3 -> SHA
14 SHA -> SDIO1
15 SHA -> SDIO3
16 AES -> SHA
17 SHA -> AES

Block transfers

First, a word is always 32 bits. Second, the block transfer specified in NDMA_CNT is the smallest atom of data that will be transferred in a burst. The bus is monopolized until this block is transferred, without splitting up.

The next block transfer will happen after the specified time in the NDMA_BLOCK_CNT interval timer, until done.

Immediate mode

Transfers the words specified in NDMA_WRITE_CNT immediately following block transfer rules. NDMA_TRANSFER_CNT and repeating mode are ignored.

Repeating mode

Transfers the words specified in NDMA_WRITE_CNT following the startup mode event. NDMA_TRANSFER_CNT is ignored.

No immediate and no repeating mode

Transfers the words specified in NDMA_WRITE_CNT for each startup event, and gets disabled when the total number of words in NDMA_TRANSFER_CNT are transferred.

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