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I have a system with a Quad-SHARC (14060 with four ADSP-21060's) and
no host. Unique images for each 21060 plus two shared images will initially reside in 8-bit EPROM. According to the ADSP-2106x SHARC User's Manual (chapter 11), there are two methods of booting a multiprocessor system: 1. Boot in turn from a single EPROM (all 21060's wired for PROM Boot) 2. One 21060 is booted, which then boots others (DSP ID 1 wired for PROM boot; others Host Boot). Our system needs to boot as fast as possible (to meet a boot-time requirement). I'm inclined to use the PROM boot loader (060_prom.ldr) in each 21060. Q1. Are there changes needed to the Analog Devices-provided 060_prom.ldr to support multiprocessor PROM Boot? Q2. Will each 21060 start executing the boot loader at the same time and arbitrate for the external bus? Q3. Should I plan on loading the shared images from PROM to internal memory in my user application (the elfloader doesn't seem to allow multiple .dxe files having the same ID using the -id<n>exe switch)? I'm grateful for any assistance! Donald M. Waldron BAE Systems Information & Electronic Warfare Systems P.O. Box 868 NHQ03-2145 Nashua, NH 03061-0868 Tel (603) 885-2461 |
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Multiprocessor Boot from 8-bit EPROM
Started by ●April 25, 2001
Reply by ●April 25, 20012001-04-25
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On Wed, 25 Apr 2001 11:14:44 -0400, Waldron, Donald M (N-BAE Systems) wrote: > I have a system with a Quad-SHARC (14060 with four ADSP-21060's) and no > host. Unique images for each 21060 plus two shared images will initially > reside in 8-bit EPROM. Similar system here, but 2 21065L's with shared SDRAM and 8-bit EPROM. The EPROM is mapped through both BMS (boot memory select) and MS1 (memory space 1) so I can both boot from it and read it at runtime without DMA, using ordinary CPU reads. > According to the ADSP-2106x SHARC User's Manual (chapter 11), there are two > methods of booting a multiprocessor system: > > 1. Boot in turn from a single EPROM (all 21060's wired for PROM Boot) > 2. One 21060 is booted, which then boots others (DSP ID 1 wired for PROM > boot; others Host Boot). We use option 1, but we also load more code later. > Our system needs to boot as fast as possible (to meet a boot-time > requirement). I'm inclined to use the PROM boot loader (060_prom.ldr) in > each 21060. Can you give more info? How fast do you need to boot? Can you do this in two steps, getting important stuff loaded immediately to meet your spec and then loading less important stuff at your leisure? You could get yet more speed by using a wider boot source and hacking the loader. > Q1. Are there changes needed to the Analog Devices-provided 060_prom.ldr > to support multiprocessor PROM Boot? Didn't need to for 21065L, which I believe uses almost the same boot loader, except for the addresses of the internal memory blocks (0x8000 vs. 0x20000?). > Q2. Will each 21060 start executing the boot loader at the same time and > arbitrate for the external bus? Correct. > Q3. Should I plan on loading the shared images from PROM to internal > memory in my user application (the elfloader doesn't seem to allow multiple > .dxe files having the same ID using the -id<n>exe switch)? I don't know what you're trying to do. The PROM image has a table that, for each ID, has an offset pointer to the matching code image. The loader kernel simply scans this table for the CPU's ID and uses the pointer found to resume loading that CPU. It wouldn't help to have a second image with the same ID, as it would never be seen. You *can* use the same image for multiple ID's, but the elfloader doesn't support using only one copy; it will write a separate copy in the EPROM for each CPU using it. It wouldn't be hard to write a post-processor that cleaned out the duplicates and fixed the pointers, though. (The load images are position-independent, so merging is simple.) If you're trying to implement a 2-stage boot, with more than one image per CPU, use the unused CPU indices for the secondary images. Elfloader doesn't support more than a 7-entry table, so you'd need to run it twice to create 2 4-entry PROM images, then write a post-processor that assembled the result into an 8-entry image. There are appnotes on the ADI site explaining the PROM image format and how the loader kernel works that I found quite helpful for this kind of stuff. |
Reply by ●April 25, 20012001-04-25
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Get EE-52 : Interfacing BYTE Programmed Flash Memories to the ADSP-2106x SHARC series EE-56 : Tips & Tricks on the ADSP-2106x EPROM and HOST bootloader EE-108 : Storing Multiple Applications in a Single Boot EPROM I found the above invaluable when I had to hack the boot loader so that I could use 16-bit wide flash. Chuck Petras Schweitzer Engineering Labs http://www.selinc.com |
