diff options
author | Dominik Sliwa <dominik.sliwa@toradex.com> | 2018-09-14 10:41:12 +0200 |
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committer | Dominik Sliwa <dominik.sliwa@toradex.com> | 2018-09-14 10:41:12 +0200 |
commit | 6142e8731c3e5b9c9f96d9af83052b9787604b39 (patch) | |
tree | 45b17840142b10874bf8974a74152eb3f9021e82 /drivers/bcma/README |
initial commit
Generated againts 4.18 kernel source with
git backports 0795d050c62e04c7c4fd7fcb554756e6adb4ec64
Signed-off-by: Dominik Sliwa <dominik.sliwa@toradex.com>
Diffstat (limited to 'drivers/bcma/README')
-rw-r--r-- | drivers/bcma/README | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/drivers/bcma/README b/drivers/bcma/README new file mode 100644 index 0000000..f7e7ce4 --- /dev/null +++ b/drivers/bcma/README @@ -0,0 +1,19 @@ +Broadcom introduced new bus as replacement for older SSB. It is based on AMBA, +however from programming point of view there is nothing AMBA specific we use. + +Standard AMBA drivers are platform specific, have hardcoded addresses and use +AMBA standard fields like CID and PID. + +In case of Broadcom's cards every device consists of: +1) Broadcom specific AMBA device. It is put on AMBA bus, but can not be treated + as standard AMBA device. Reading it's CID or PID can cause machine lockup. +2) AMBA standard devices called ports or wrappers. They have CIDs (AMBA_CID) + and PIDs (0x103BB369), but we do not use that info for anything. One of that + devices is used for managing Broadcom specific core. + +Addresses of AMBA devices are not hardcoded in driver and have to be read from +EPROM. + +In this situation we decided to introduce separated bus. It can contain up to +16 devices identified by Broadcom specific fields: manufacturer, id, revision +and class. |