OpenSBI debug console support

The latest proposal of SBI debug console extension can be found at:
https://lists.riscv.org/g/tech-prs/message/96

This series implements SBI debug console support in OpenSBI as-per above draft proposal.

To test these patches corresponding Linux patches can be found in riscv_sbi_dbcn_v1 branch at: https://github.com/avpatel/linux.git

These patches can also be found in riscv_sbi_dbcn_v6 branch at:
https://github.com/avpatel/opensbi.git

Changes since v5:
- Rebased on latest OpenSBI sources
- Updated Reviewed-by tags
- Addressed Drew's comments in all patches
- Updated SBI debug console implementation as-per latest proposal where console write() is non-blocking.

Changes since v4:
- Rebased on latest OpenSBI sources
- Updated Reviewed-by tags
- Added new PATCH8 to speed-up sbi_printf() using nputs()

Changes since v3:
- Rebased on OpenSBI v1.2 release
- Updated Reviewed-by tags
- Added new PATCH3 for sbi_ngets() function
- Updated SBI debug console implementation in PATCH5 as-per latest proposal having both console write() and read() functions.

Changes since v2:
- Reworked sbi_domain_check_addr_range() in PATCH3 to make it work for overlapping regions.

Changes since v1:
- New PATCH3 to implement sbi_domain_check_addr_range() function
- Added checks in PATCH4 for location and size of string to print
- New PATCH5 to add console_puts() callback in the console device
- New PATCH6 to implement console_puts() for semihosting

Anup Patel (8):
include: Add defines for SBI debug console extension
lib: sbi: Add sbi_nputs() function
lib: sbi: Add sbi_ngets() function
lib: sbi: Add sbi_domain_check_addr_range() function
lib: sbi: Implement SBI debug console extension
lib: sbi: Add console_puts() callback in the console device
lib: utils/serial: Implement console_puts() for semihosting
lib: sbi: Speed-up sbi_printf() and friends using nputs()

 include/sbi/sbi_console.h         |  7 +++
 include/sbi/sbi_domain.h          | 15 ++++++
 include/sbi/sbi_ecall_interface.h |  6 +++
 lib/sbi/Kconfig                   |  4 ++
 lib/sbi/objects.mk                |  3 ++
 lib/sbi/sbi_console.c             | 88 ++++++++++++++++++++++++++++---
 lib/sbi/sbi_domain.c              | 69 ++++++++++++++++++++++++
 lib/sbi/sbi_ecall_dbcn.c          | 72 +++++++++++++++++++++++++
 lib/utils/serial/semihosting.c    | 37 +++++++++++++
 9 files changed, 294 insertions(+), 7 deletions(-)
 create mode 100644 lib/sbi/sbi_ecall_dbcn.c

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2.34.1