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raspberry pi
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broadcom 2835 SoC (based on 2708)
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arm1176jzf-s (v6 arch) 700MHz cpu, apparently dual-issue, with vfp2
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videocore 4 gpu
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6 |
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l1 I & D VIPT caches
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16K each: 4-way, 128 sets, 32-byte lines
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l1 D is write-through, l1 I is write-back
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unified l2 PIPT cache 128K: 4-way?, 1024? sets, 32-byte lines, mostly for gpu
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(by default CPU doesn't see it)
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12 |
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we arrange that device register accesses are uncached and unbuffered
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(strongly ordered, in armv6/v7 terminology).
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15 |
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256MB or 512MB of dram at physical address 0, shared with gpu
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non-16550 uart for console
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18 |
uart serial voltages are TTL (3.3v, not rs232 which is nominally 12v);
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could use usb serial (ick).
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there's no real ethernet controller, so we have to use usb ether,
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and the usb controller is nastier than usual.
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There's a serial port (115200b/s) on P1 connector pins (GND,TXD,RXD) =
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(6,8,10). These are 3v TTL signals: use a level-shifter to convert to
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RS232, or a USB-to-TTL-serial adapter. Add the line "console=0
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b115200" to the /cfg/pxe file on the server, or the parameter
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"console='0 b115200'" to cmdline.txt on the SD card.
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28 |
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9pi is a Plan 9 terminal, which can boot with local fossil root on the
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sd card (/dev/sdM0), or with root from a Plan 9 file server via tcp.
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9picpu is a Plan 9 cpu server, which could be used in a headless
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configuration without screen, keyboard or mouse.
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9pifat is a minimal configuration which boots a shell script boot.rc
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with root in /plan9 on the dos partition, maybe useful for embedded
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applications where a full Plan 9 system is not needed.
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Network booting with u-boot:
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start with a normal rpi u-boot sd (e.g. raspberry-pi-uboot-20120707).
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update the start.elf with a version from a newer rpi distro (see below).
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mk installall
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add new system to ndb
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see booting(8)
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Booting from sd card:
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- start with a normal rpi distro sd (e.g. 2012-08-16-wheezy-raspbian)
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[NB: versions of start.elf earlier than this may not be compatible]
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- copy 9pi to sd's root directory
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- add or change "kernel=" line in config.txt to "kernel=9pi"
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- plan9.ini is built from the "kernel arguments" in cmdline.txt - each
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var=value entry becomes one plan9.ini line, so entries with spaces will
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need single quotes.
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54 |
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55 |
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physical mem map
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57 |
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hex addr size what
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----
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00000000 64 exception vectors
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00000100 7936 boot ATAGs (inc. cmdline.txt)
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00002000 4K Mach
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00003000 1K L2 page table for exception vectors
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00003400 1K videocore mailbox buffer
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00003800 2K FIQ stack
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00004000 16K L1 page table for kernel
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00008000 - default kernel load address
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01000000 16K u-boot env
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20000000 16M peripherals
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20003000 system timer(s)
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20007000 dma
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2000B000 arm control: intr, timers 0 & 1, semas, doorbells, mboxes
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20100000 power, reset, watchdog
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20200000 gpio
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20201000 uart0
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20202000 mmc
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20215040 uart1 (mini uart)
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20300000 eMMC
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20600000 smi
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20980000 otg usb
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40000000 l2 cache only
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7e00b000 arm control
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7e2000c0 jtag
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7e201000? pl011 usrt
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7e215000 aux: uart1, spi[12]
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80000000
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c0000000 bypass caches
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virtual mem map (from cpu address map & mmu mappings)
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hex addr size what
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----
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7e000000 16M i/o registers
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80000000 <=224M kzero, kernel ram (reserve some for GPU)
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ffff0000 4K exception vectors
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101 |
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Linux params at *R2 (default 0x100) are a sequence of ATAGs
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struct atag {
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u32int size; /* size of ATAG in words, including header */
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u32int tag; /* ATAG_CORE is first, ATAG_NONE is last */
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u32int data[size-2];
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};
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00000000 ATAG_NONE
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54410001 ATAG_CORE
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54410002 ATAG_MEM
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54410009 ATAG_CMDLINE
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113 |
uart dmas 15, 14
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intrs (96)
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irq1
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118 |
1 timer1
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2 timer2
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3 timer3
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8 isp
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122 |
9 usb
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16 dma0
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17 dma1
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⋯
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126 |
28 dma12
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127 |
29 aux: uart1
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128 |
30 arm
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129 |
31 vpu dma
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130 |
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131 |
irq2
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132 |
35 sdc
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36 dsio
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134 |
40 hdmi0
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41 hdmi1
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136 |
48 smi
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56 sdio
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138 |
57 uart1 aka "vc uart"
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139 |
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140 |
irq0
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141 |
64 timer
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65 mbox
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66 doorbell0
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67 doorbell1
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75 usb
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77 dma2
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78 dma3
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148 |
82 sdio
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149 |
83 uart0
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