diff options
author | root <root@artemis.panaceas.org> | 2015-12-25 15:00:15 +0000 |
---|---|---|
committer | root <root@artemis.panaceas.org> | 2015-12-25 15:00:15 +0000 |
commit | ddd86436f4e3643c04b797f858dab95d5f2e4de9 (patch) | |
tree | bfe7a780cf9a2f4fc33aec32c82e625e79dece1f /drivers/bcma/README | |
download | backports-3.10.19-1-master.tar.gz backports-3.10.19-1-master.tar.bz2 backports-3.10.19-1-master.zip |
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. |