dev, arm: Warn on PL011 DMA disable
The PL011 spec specifies a DMACR register at offset 0x48, which isn't
implemented in the model. Currently any attempt to access the register
results in a panic.
This change swaps the panic for a warning only when software writes into
DMACR to disable DMA, keeping the panic otherwise.
Change-Id: I04586b52df8d5d174536276fd7ae19e77ff4681a
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/15279
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
diff --git a/src/dev/arm/pl011.cc b/src/dev/arm/pl011.cc
old mode 100644
new mode 100755
index fe73d96..2e80045
--- a/src/dev/arm/pl011.cc
+++ b/src/dev/arm/pl011.cc
@@ -133,6 +133,10 @@
DPRINTF(Uart, "Reading Masked Int status as 0x%x\n", maskInt());
data = maskInt();
break;
+ case UART_DMACR:
+ warn("PL011: DMA not supported\n");
+ data = 0x0; // DMA never enabled
+ break;
default:
if (readId(pkt, AMBA_ID, pioAddr)) {
// Hack for variable size accesses
@@ -239,6 +243,14 @@
dataAvailable();
}
break;
+ case UART_DMACR:
+ // DMA is not supported, so panic if anyome tries to enable it.
+ // Bits 0, 1, 2 enables DMA on RX, TX, ERR respectively, others res0.
+ if (data & 0x7) {
+ panic("Tried to enable DMA on PL011\n");
+ }
+ warn("PL011: DMA not supported\n");
+ break;
default:
panic("Tried to write PL011 at offset %#x that doesn't exist\n", daddr);
break;
diff --git a/src/dev/arm/pl011.hh b/src/dev/arm/pl011.hh
old mode 100644
new mode 100755
index 5a92d88..dac2f68
--- a/src/dev/arm/pl011.hh
+++ b/src/dev/arm/pl011.hh
@@ -135,6 +135,7 @@
static const int UART_RIS = 0x03C;
static const int UART_MIS = 0x040;
static const int UART_ICR = 0x044;
+ static const int UART_DMACR = 0x048;
static const uint16_t UART_RIINTR = 1 << 0;
static const uint16_t UART_CTSINTR = 1 << 1;