u-boot-brain/board/amcc
Stefan Roese e2e93442e5 ppc4xx: Fix bug in I2C bootstrap values for Sequoia/Rainier
The I2C bootstrap values that can be setup via the "bootstrap" command,
were setup incorrect regarding the generation of the internal sync PCI
clock. The values for PLB clock == 133MHz were slighly incorrect and the
values for PLB clock == 166MHz were totally incorrect. This could
lead to a hangup upon booting while PCI configuration scan.

This patch fixes this issue and configures valid PCI divisor values
for the sync PCI clock, with respect to the provided external async
PCI frequency.

Here the values of the formula in the chapter 14.2 "PCI clocking"
from the 440EPx users manual:

AsyncPCICLK - 1MHz <= SyncPCIClk <= (2 * AsyncPCIClk) - 1MHz

33MHz async PCI frequency:
PLB = 133:
=>      32 <= 44.3 <= 65        (div = 3)

PLB = 166:
=>      32 <= 55.3 <= 65        (div = 3)

66MHz async PCI frequency:
PLB = 133:
=>      65 <= 66.5 <= 132       (div = 2)

PLB = 166:
=>      65 <= 83 <= 132         (div = 2)

Signed-off-by: Stefan Roese <sr@denx.de>
2007-10-15 11:39:00 +02:00
..
acadia Coding stylke cleanup; rebuild CHANGELOG 2007-06-22 23:59:00 +02:00
bamboo ppc4xx: Update AMCC Bamboo 440EP support 2007-07-31 10:24:56 +02:00
bubinga ppc4xx: Add initial Zeus (PPC405EP) board support 2007-08-14 14:44:41 +02:00
common ppc4xx: Update AMCC Bamboo 440EP support 2007-07-31 10:24:56 +02:00
ebony ppc4xx: Add pci_pre_init() for 405 boards 2007-06-25 15:57:39 +02:00
katmai Fix cases where DECLARE_GLOBAL_DATA_PTR was not declared as global 2007-09-15 20:48:41 +02:00
luan ppc4xx: Coding style cleanup 2007-10-02 11:44:46 +02:00
ocotea ppc4xx: Add pci_pre_init() for 405 boards 2007-06-25 15:57:39 +02:00
sequoia ppc4xx: Fix bug in I2C bootstrap values for Sequoia/Rainier 2007-10-15 11:39:00 +02:00
taihu ppc4xx: Add initial Zeus (PPC405EP) board support 2007-08-14 14:44:41 +02:00
taishan Fix cases where DECLARE_GLOBAL_DATA_PTR was not declared as global 2007-09-15 20:48:41 +02:00
walnut Move "ar" flags to config.mk to allow for silent "make -s" 2006-10-09 01:02:05 +02:00
yosemite ppc4xx: Fix incorrect 33/66MHz PCI clock log-message on Sequoia & Yosemite 2007-10-15 11:29:33 +02:00
yucca Fix cases where DECLARE_GLOBAL_DATA_PTR was not declared as global 2007-09-15 20:48:41 +02:00