* [U-Boot] Need answers of basic questions regarding u-boot @ 2011-08-07 18:55 Rakesh Modi 2011-08-07 20:28 ` Jerry Van Baren 0 siblings, 1 reply; 6+ messages in thread From: Rakesh Modi @ 2011-08-07 18:55 UTC (permalink / raw) To: u-boot Hi, I am new to linux and u-boot. Please answer my following questions. 1) what is u-boot? why it require? 2) why we can not load linux kernel directly without use of u-boot? 3) How does any processor sequence starts when power is on? -- Thanks & Regards Rakesh Modi ^ permalink raw reply [flat|nested] 6+ messages in thread
* [U-Boot] Need answers of basic questions regarding u-boot 2011-08-07 18:55 [U-Boot] Need answers of basic questions regarding u-boot Rakesh Modi @ 2011-08-07 20:28 ` Jerry Van Baren 2011-08-08 5:54 ` Hebbar, Gururaja 0 siblings, 1 reply; 6+ messages in thread From: Jerry Van Baren @ 2011-08-07 20:28 UTC (permalink / raw) To: u-boot On 08/07/2011 02:55 PM, Rakesh Modi wrote: > Hi, > I am new to linux and u-boot. Please answer my following questions. > 1) what is u-boot? why it require? It initializes and configures the hardware (processor, RAM, peripherals), it loads linux (or other OS) from storage (flash, hard drive, ethernet, other) into RAM and then passes control to linux. While it isn't required, it is very convenient to have it. The other features of u-boot are that u-boot can be used to load new linux images into your storage device. The general principle is that u-boot is not often replaced on a board, but the linux image is updated and upgraded regularly. > 2) why we can not load linux kernel directly without use of u-boot? You can, but you need to do the hardware initialization and configuration in the linux start up code. You will also have to create a method to and mechanism for linux to upgrade itself, preferably in a "failure resistant" way so that you don't "brick" your board inadvertently by having a failure when upgrading linux. U-boot has solved these problems already for you. > 3) How does any processor sequence starts when power is on? That is described in the processor hardware reference manual. It is different for each processor, but in general the processor starts fetching and executing code from a known location - sometimes from a fixed memory address, sometimes it fetches a pointer from a fixed memory address and starts executing from the address pointed to. Best regards, gvb ^ permalink raw reply [flat|nested] 6+ messages in thread
* [U-Boot] Need answers of basic questions regarding u-boot 2011-08-07 20:28 ` Jerry Van Baren @ 2011-08-08 5:54 ` Hebbar, Gururaja 2011-08-10 10:09 ` Detlev Zundel 0 siblings, 1 reply; 6+ messages in thread From: Hebbar, Gururaja @ 2011-08-08 5:54 UTC (permalink / raw) To: u-boot Hi, We need to make this sticky or add it into some wiki page. Nice explanation for beginners. Regards Gururaja On Mon, Aug 08, 2011 at 01:58:32, Jerry Van Baren wrote: > On 08/07/2011 02:55 PM, Rakesh Modi wrote: > > Hi, > > I am new to linux and u-boot. Please answer my following questions. > > 1) what is u-boot? why it require? > > It initializes and configures the hardware (processor, RAM, peripherals), it loads linux (or other OS) from storage (flash, hard drive, ethernet, other) into RAM and then passes control to linux. > > While it isn't required, it is very convenient to have it. The other features of u-boot are that u-boot can be used to load new linux images into your storage device. The general principle is that u-boot is not often replaced on a board, but the linux image is updated and upgraded regularly. > > > 2) why we can not load linux kernel directly without use of u-boot? > > You can, but you need to do the hardware initialization and configuration in the linux start up code. You will also have to create a method to and mechanism for linux to upgrade itself, preferably in a "failure resistant" way so that you don't "brick" your board inadvertently by having a failure when upgrading linux. > > U-boot has solved these problems already for you. > > > 3) How does any processor sequence starts when power is on? > > That is described in the processor hardware reference manual. It is different for each processor, but in general the processor starts fetching and executing code from a known location - sometimes from a fixed memory address, sometimes it fetches a pointer from a fixed memory address and starts executing from the address pointed to. > > Best regards, > gvb > _______________________________________________ > U-Boot mailing list > U-Boot at lists.denx.de > http://lists.denx.de/mailman/listinfo/u-boot > Regards, Gururaja ^ permalink raw reply [flat|nested] 6+ messages in thread
* [U-Boot] Need answers of basic questions regarding u-boot 2011-08-08 5:54 ` Hebbar, Gururaja @ 2011-08-10 10:09 ` Detlev Zundel 2011-08-10 10:23 ` Hebbar, Gururaja 0 siblings, 1 reply; 6+ messages in thread From: Detlev Zundel @ 2011-08-10 10:09 UTC (permalink / raw) To: u-boot Hi Gururaja, > We need to make this sticky or add it into some wiki page. Who exactly is we? :) <hint> Well wikis are, ahem, wikis, i.e. changeable by everyone </hint> Cheers Detlev -- I have always observed that the pretensions of all people are in exact inverse ratio to their merits; this is one of the axioms of morals. -- Joseph Lagrange -- DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-40 Fax: (+49)-8142-66989-80 Email: dzu at denx.de ^ permalink raw reply [flat|nested] 6+ messages in thread
* [U-Boot] Need answers of basic questions regarding u-boot 2011-08-10 10:09 ` Detlev Zundel @ 2011-08-10 10:23 ` Hebbar, Gururaja 2011-08-10 12:19 ` Detlev Zundel 0 siblings, 1 reply; 6+ messages in thread From: Hebbar, Gururaja @ 2011-08-10 10:23 UTC (permalink / raw) To: u-boot By "we" I meant the gr8 u-boot community. I know at present there isn't a place on web for u-boot but surely I would help if someone starts. Regards Gururaja > -----Original Message----- > From: Detlev Zundel [mailto:dzu at denx.de] > Sent: Wednesday, August 10, 2011 3:39 PM > To: Hebbar, Gururaja > Cc: Jerry Van Baren; Rakesh Modi; u-boot at lists.denx.de > Subject: Re: [U-Boot] Need answers of basic questions regarding u-boot > > Hi Gururaja, > > > We need to make this sticky or add it into some wiki page. > > Who exactly is we? :) > > <hint> Well wikis are, ahem, wikis, i.e. changeable by everyone </hint> > > Cheers > Detlev > > -- > I have always observed that the pretensions of all people are in > exact inverse ratio to their merits; this is one of the axioms of > morals. -- Joseph Lagrange > -- > DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel > HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany > Phone: (+49)-8142-66989-40 Fax: (+49)-8142-66989-80 Email: dzu at denx.de ^ permalink raw reply [flat|nested] 6+ messages in thread
* [U-Boot] Need answers of basic questions regarding u-boot 2011-08-10 10:23 ` Hebbar, Gururaja @ 2011-08-10 12:19 ` Detlev Zundel 0 siblings, 0 replies; 6+ messages in thread From: Detlev Zundel @ 2011-08-10 12:19 UTC (permalink / raw) To: u-boot Hi Gururaja, > By "we" I meant the gr8 u-boot community. I know at present there > isn't a place on web for u-boot but surely I would help if someone > starts. You really missed http://www.denx.de/wiki/U-Boot/WebHome up until now? I'm looking forward to see your registration ;) Cheers Detlev -- #!/usr/bin/perl $c="print\"\#\!\/usr\/bin\/perl\ \\\$c\=\\\"\"\.quotemeta\(\$c\)\.\"\\\"\;\\n\$c;\""; print"#!/usr/bin/perl\n\$c=\"".quotemeta($c)."\";\n$c;"; -- DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-40 Fax: (+49)-8142-66989-80 Email: dzu at denx.de ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2011-08-10 12:19 UTC | newest] Thread overview: 6+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2011-08-07 18:55 [U-Boot] Need answers of basic questions regarding u-boot Rakesh Modi 2011-08-07 20:28 ` Jerry Van Baren 2011-08-08 5:54 ` Hebbar, Gururaja 2011-08-10 10:09 ` Detlev Zundel 2011-08-10 10:23 ` Hebbar, Gururaja 2011-08-10 12:19 ` Detlev Zundel
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