The branch main has been updated by imp:
URL:
https://cgit.FreeBSD.org/src/commit/?id=dea3eef94cafb3bb1e5f04bc96b5636ffca92ee7
commit dea3eef94cafb3bb1e5f04bc96b5636ffca92ee7
Author: Warner Losh <i...@freebsd.org>
AuthorDate: 2025-01-15 02:17:46 +0000
Commit: Warner Losh <i...@freebsd.org>
CommitDate: 2025-01-15 02:24:35 +0000
uart: Ingore pl011 historic mistakes
Some veresions of EDK-II and QEMU reported the wrong values for the
register shift and the region I/O size. Detect those and set it to the
correct values. In general, anything other than a shift of 2 and a
regio width of 4 (bytes, or 32 bits) is a mistake. However, allow
for overrides in the future by only overriding the buggy values.
Otherwise, we will fail to boot.
PR: 282936
Sponsored by: Netflix
Reviewed by: emaste
Differential Revision: https://reviews.freebsd.org/D47946
---
sys/dev/uart/uart_dev_pl011.c | 24 +++++++++++++++++++++++-
1 file changed, 23 insertions(+), 1 deletion(-)
diff --git a/sys/dev/uart/uart_dev_pl011.c b/sys/dev/uart/uart_dev_pl011.c
index 4f946f7c5f36..e7a2ff7a85f1 100644
--- a/sys/dev/uart/uart_dev_pl011.c
+++ b/sys/dev/uart/uart_dev_pl011.c
@@ -172,6 +172,27 @@ static int
uart_pl011_probe(struct uart_bas *bas)
{
+ /*
+ * Versions of QEMU before 41f7b58b634e (8.3) reported bogus values for
+ * this tabel. The PL011 IP is always 32-bits wide and should be shifted
+ * 2 to match the 4-byte size of the data. QEMU reported these values
+ * incorrectly before that.
+ *
https://github.com/qemu/qemu/commit/41f7b58b634ec3b60ae874375d2bbb61d790971e
+ *
+ * In additon, other hardware vendors also reported this value
+ * incorrectly. It's not tied to what the ACPI device node is, but was a
+ * misunderstanding coupled with a Linux driver that didn't need the
+ * right values. Quirks used to be used to ignore the bad values, now we
+ * detect the historic mistake and override (to allow for a future where
+ * we may need to override these values).
+ *
+ * PL011 Docs: https://developer.arm.com/documentation/ddi0183/latest/
+ */
+ if (bas->regshft == 0 || bas->regiowidth == 1) {
+ bas->regshft = 2;
+ bas->regiowidth = 4;
+ }
+
return (0);
}
@@ -356,7 +377,8 @@ static struct uart_class uart_pl011_class = {
.uc_ops = &uart_pl011_ops,
.uc_range = 0x48,
.uc_rclk = 0,
- .uc_rshift = 2
+ .uc_rshift = 2,
+ .uc_riowidth = 4,
};
UART_CLASS(uart_pl011_class);
