Add SBE driver support

SBE (Self Boot Engine) on P9 has two different jobs:
  - Boot the chip up to the point the core is functional
  - Provide various services like timer, scom, stash MPIPL, etc., at runtime

OPAL can communicate to SBE via a set of data and control registers provided
by the PSU block in P9 chip.
 - Four 8 byte registers for Host to send command packets to SBE
 - Four 8 byte registers for SBE to send response packets to Host
 - Two doorbell registers (1 on each side) to alert either party
   when data is placed in above mentioned data register

Protocol constraints:
  Only one command is accepted in the command buffer until the response for the
  command is enqueued in the response buffer by SBE.

Usage:
  We will use SBE for various purposes like timer, MPIPL, etc.

This patch implements the SBE MBOX spec for OPAL to communicate with
SBE.

Design consideration:
  - Each chip has SBE. We need to track SBE messages per chip. Hence added
    per chip sbe structure and list of messages to that chip
  - SBE accepts only one command at a time. Hence serialized MBOX commands.
  - OPAL gets interrupted once SBE sets doorbell register
  - OPAL has to clear doorbell register after reading response
  - Every command class has timeout option. Timed out messages are discarded
  - SBE MBOX commands can be classified into four types :
    - Those that must be sent to the master only (ex: sending MDST/MDDT info)
    - Those that must be sent to slaves only (ex: continue MPIPL)
    - Those that must be sent to all chips (ex: close insecure window)
    - Those that can be sent to any chip (ex: timer)

Signed-off-by: Vasant Hegde <hegdevasant@linux.vnet.ibm.com>
Signed-off-by: Stewart Smith <stewart@linux.ibm.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/include/chip.h b/include/chip.h
index 43b5ea55..059033e2 100644
--- a/include/chip.h
+++ b/include/chip.h
@@ -113,6 +113,7 @@ struct mfsi;
 struct xive;
 struct lpcm;
 struct vas;
+struct p9_sbe;
 
 /* Chip type */
 enum proc_chip_type {
@@ -218,6 +219,9 @@ struct proc_chip {
 
 	/* location code of this chip */
 	const uint8_t		*loc_code;
+
+	/* Used by hw/sbe-p9.c */
+	struct p9_sbe		*sbe;
 };
 
 extern uint32_t pir_to_chip_id(uint32_t pir);