The branch main has been updated by imp:
URL:
https://cgit.FreeBSD.org/src/commit/?id=501983e62e754d0b260c0dfe7f23042c89acd9f1
commit 501983e62e754d0b260c0dfe7f23042c89acd9f1
Author: Warner Losh <i...@freebsd.org>
AuthorDate: 2024-10-15 11:12:59 +0000
Commit: Warner Losh <i...@freebsd.org>
CommitDate: 2024-10-15 11:12:59 +0000
loader.efi: Parse SPCR v3 and v4
We can get the UART clock from v3 SPCR, and a precise baudrate from
v4. Some precise baudrates will currently be rejected by the kernel.
Sponsored by: Netflix
Reviewed by: adrian, andrew
Differential Revision: https://reviews.freebsd.org/D47096
---
stand/efi/loader/main.c | 24 +++++++++++++++++-------
1 file changed, 17 insertions(+), 7 deletions(-)
diff --git a/stand/efi/loader/main.c b/stand/efi/loader/main.c
index e8db72bf4c8a..0e2c580d1a8a 100644
--- a/stand/efi/loader/main.c
+++ b/stand/efi/loader/main.c
@@ -888,14 +888,24 @@ check_acpi_spcr(void)
db = 8;
/*
- * Note: We don't support SPCR Rev3 or Rev4 so use Rev2 values, if we
- * did we wouldn't have to do this weird dances with baud or xtal rates.
- * Rev 3 and 4 are too new to have seen any deployment, and aren't in
- * the system's actblX.h files yet. This will fail for newer high-speed
- * consoles until acpica catches up with Microsoft's new definitions.
+ * UartClkFreq is 3 and newer. We always use it then (it's only valid if
+ * it isn't 0, but if it is 0, we want to use 0 to have the kernel
+ * guess).
*/
- xo = 0;
- br = acpi_uart_baud(spcr->BaudRate);
+ if (spcr->Header.Revision <= 2)
+ xo = 0;
+ else
+ xo = spcr->UartClkFreq;
+
+ /*
+ * PreciseBaudrate, when non-zero, is to be preferred. It's only valid,
+ * though, for rev 4 and newer. So when it's 0 or the version is too
+ * old, we do the old-style table lookup. Otherwise we believe it.
+ */
+ if (spcr->Header.Revision <= 3 || spcr->PreciseBaudrate == 0)
+ br = acpi_uart_baud(spcr->BaudRate);
+ else
+ br = spcr->PreciseBaudrate;
if (io != -1) {
asprintf(&val, "db:%d,dt:%s,io:%#x,pa:%s,br:%d,xo=%d",
