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From: Antony Pavlov <antonynpavlov@gmail.com>
To: barebox@lists.infradead.org
Subject: [PATCH v9 05/12] MIPS: add documentation
Date: Wed,  3 Aug 2011 13:10:54 +0400	[thread overview]
Message-ID: <1312362661-31340-5-git-send-email-antonynpavlov@gmail.com> (raw)
In-Reply-To: <1312362661-31340-1-git-send-email-antonynpavlov@gmail.com>

Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
---
 arch/architecture.dox   |    1 +
 arch/mips/mach-mips.dox |   54 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 55 insertions(+), 0 deletions(-)
 create mode 100644 arch/mips/mach-mips.dox

diff --git a/arch/architecture.dox b/arch/architecture.dox
index 67e2c38..2d2cf05 100644
--- a/arch/architecture.dox
+++ b/arch/architecture.dox
@@ -86,6 +86,7 @@ TODO
 
 @li @subpage dev_arm_mach
 @li @subpage dev_bf_mach
+@li @subpage dev_mips_mach
 @li @subpage dev_ppc_mach
 @li @subpage dev_x86_mach
 
diff --git a/arch/mips/mach-mips.dox b/arch/mips/mach-mips.dox
new file mode 100644
index 0000000..018fc44
--- /dev/null
+++ b/arch/mips/mach-mips.dox
@@ -0,0 +1,54 @@
+/* This document is intended to provide the developer with information
+ * how to integrate a new CPU (MACH) into this part of the barebox tree
+ */
+
+/** @page dev_mips_mach MIPS based CPU (MACH) into the tree
+
+@section mach_mips_reset What's happens when the reset signal is gone
+
+Barebox normally must be linked to RAM region, cached region KSEG0 is preferred.
+This make possible to run fast (because cache used) and skip MMU support.
+
+After reset MIPS CPU starting to fetch instructions from 0xBFC00000.
+
+@note Code running immediately after reset runs at an address it is not linked
+      to: "runtime address != link address". You should only use branches and
+      do not refer to fixed data. This implies the use of assembler code only.
+      After MIPS CPU reset cache and MMU are in random state. They are unusable.
+
+barebox MIPS initialisation sequence:
+
+ * set the CP0 STATUS register to some known and sensible state.
+Now you can load and store reliably in uncached space.
+
+ * call a function \<mach_init_lowlevel\> (if not disabled).
+do some special things required only on specific CPU
+ (e. g. init RAM controller, disable watchdog)
+
+ * call a function \<board_init_lowlevel\> (if not disable).
+do some special things required only on specific board
+ (e. g. setup GPIO to required state).
+
+   ** It is desirable to have some debug code to make some contact
+ with the outside world from assembler code
+(e.g. debug_ll-like functions to write to rs232 console).
+
+ * check integrity of barebox RAM execute location;
+ * copy barebox to RAM execute location;
+
+ * configure cache;
+
+ * setup stack;
+
+   ** after this point you can call a standard C routine.
+
+ * setup exception vectors in RAM;
+ * setup CP0 STATUS to switch exception vector address to RAM;
+
+ * call start_barebox()
+
+Further reading:
+ * Dominic Sweetman, See MIPS Run, Morgan Kaufmann, 2nd edition, 2006
+ISBN-13: 978-0120884216
+
+*/
-- 
1.7.5.4


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  parent reply	other threads:[~2011-08-03  9:11 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-08-03  9:10 [PATCH v9 01/12] MIPS: initial commit: add empty but required header files Antony Pavlov
2011-08-03  9:10 ` [PATCH v9 02/12] MIPS: import libgcc-related files from linux-2.6.39 Antony Pavlov
2011-08-03  9:10 ` [PATCH v9 03/12] MIPS: import header files Antony Pavlov
2011-08-03  9:10 ` [PATCH v9 04/12] MIPS: add common MIPS stuff Antony Pavlov
2011-08-03 12:54   ` Jean-Christophe PLAGNIOL-VILLARD
2011-08-03 13:53     ` Antony Pavlov
2011-08-03  9:10 ` Antony Pavlov [this message]
2011-08-03  9:10 ` [PATCH v9 06/12] MIPS: add Malta machine support to barebox Antony Pavlov
2011-08-03  9:10 ` [PATCH v9 07/12] MIPS: add qemu malta board " Antony Pavlov
2011-08-03  9:10 ` [PATCH v9 08/12] MIPS: add qemu-malta documentation Antony Pavlov
2011-08-03  9:10 ` [PATCH v9 09/12] MIPS: add initial BCM47xx-based boards support Antony Pavlov
2011-08-03  9:10 ` [PATCH v9 10/12] MIPS: add initial D-Link DIR-320 wireless router support Antony Pavlov
2011-08-03  9:11 ` [PATCH v9 11/12] MIPS: add D-Link DIR-320 documentation Antony Pavlov
2011-08-03  9:11 ` [PATCH v9 12/12] MIPS: add draft cpuinfo command Antony Pavlov

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