Hi Andrey,
On 12/7/22 12:45, Andrey Makarov wrote:
There is nothing in the specs on DMA engine interrupt lines: it should have
been in the "BCM2835 ARM Peripherals" datasheet but the appropriate
"ARM peripherals interrupt table" (p.113) is nearly empty.
All Raspberry Pi models 1-3 (based on bcm2835) have
Linux device tree (arch/arm/boot/dts/bcm2835-common.dtsi +25):
/* dma channel 11-14 share one irq */
This information is repeated in the driver code
(drivers/dma/bcm2835-dma.c +1344):
/*
* in case of channel >= 11
* use the 11th interrupt and that is shared
*/
In this patch channels 0--10 and 11--14 are handled separately.
In version v2:
1) an OR-gate is added according to review
2) a simple qtest is added for testing DMA & its interrupts
Signed-off-by: Andrey Makarov <andrey.maka...@auriga.com>
---
hw/arm/bcm2835_peripherals.c | 21 +++++-
include/hw/arm/bcm2835_peripherals.h | 2 +
tests/qtest/bcm2835-dma-test.c | 106 +++++++++++++++++++++++++++
tests/qtest/meson.build | 3 +-
4 files changed, 130 insertions(+), 2 deletions(-)
create mode 100644 tests/qtest/bcm2835-dma-test.c
diff --git a/hw/arm/bcm2835_peripherals.c b/hw/arm/bcm2835_peripherals.c
index 48538c9360..5a9c472b5a 100644
--- a/hw/arm/bcm2835_peripherals.c
+++ b/hw/arm/bcm2835_peripherals.c
@@ -101,6 +101,11 @@ static void bcm2835_peripherals_init(Object *obj)
/* DMA Channels */
object_initialize_child(obj, "dma", &s->dma, TYPE_BCM2835_DMA);
+ object_initialize_child(obj, "dma-11-14-irq-orgate",
Maybe name "shared-dma-irq-orgate"?
+ &s->dma_11_14_irq_orgate, TYPE_OR_IRQ);
Similarly 'shared_dma' or 'orgated-dma'? But not _11_14_.
+ object_property_set_int(OBJECT(&s->dma_11_14_irq_orgate), "num-lines", 4,
Instead of using a magic number:
#define BCM2835_SHARED_DMA_COUNT 4
+ &error_abort);
+
object_property_add_const_link(OBJECT(&s->dma), "dma-mr",
OBJECT(&s->gpu_bus_mr));
@@ -322,13 +327,27 @@ static void bcm2835_peripherals_realize(DeviceState *dev, Error **errp)
memory_region_add_subregion(&s->peri_mr, DMA15_OFFSET,
sysbus_mmio_get_region(SYS_BUS_DEVICE(&s->dma), 1));
- for (n = 0; n <= 12; n++) {
+ for (n = 0; n <= 10; n++) {
So before we could trigger IRQ #12, and now it is unbound?
Also:
#define BCM2835_DMA_CHANNELS 10
sysbus_connect_irq(SYS_BUS_DEVICE(&s->dma), n,
qdev_get_gpio_in_named(DEVICE(&s->ic),
BCM2835_IC_GPU_IRQ,
INTERRUPT_DMA0 + n));
}
+ /* According to DTS, dma channels 11-14 share one irq */
+ if (!qdev_realize(DEVICE(&s->dma_11_14_irq_orgate), NULL, errp)) {
+ return;
+ }
+ for (n = 11; n <= 14; n++) {
Logic simplified if you use the [0 .. BCM2835_SHARED_DMA_COUNT-1] range:
for (n = 0; n < BCM2835_SHARED_DMA_COUNT; n++) {
+ sysbus_connect_irq(SYS_BUS_DEVICE(&s->dma), n,
BCM2835_DMA_CHANNELS + 1 + n,
+ qdev_get_gpio_in(DEVICE(&s->dma_11_14_irq_orgate),
+ n - 11));
n)
+ }
+ qdev_connect_gpio_out(DEVICE(&s->dma_11_14_irq_orgate), 0,
+ qdev_get_gpio_in_named(DEVICE(&s->ic),
+ BCM2835_IC_GPU_IRQ,
+ INTERRUPT_DMA0 + 11));
+
/* THERMAL */
if (!sysbus_realize(SYS_BUS_DEVICE(&s->thermal), errp)) {
return;
diff --git a/include/hw/arm/bcm2835_peripherals.h
b/include/hw/arm/bcm2835_peripherals.h
index d864879421..79e2f2771a 100644
--- a/include/hw/arm/bcm2835_peripherals.h
+++ b/include/hw/arm/bcm2835_peripherals.h
@@ -17,6 +17,7 @@
#include "hw/char/bcm2835_aux.h"
#include "hw/display/bcm2835_fb.h"
#include "hw/dma/bcm2835_dma.h"
+#include "hw/or-irq.h"
#include "hw/intc/bcm2835_ic.h"
#include "hw/misc/bcm2835_property.h"
#include "hw/misc/bcm2835_rng.h"
@@ -55,6 +56,7 @@ struct BCM2835PeripheralState {
BCM2835AuxState aux;
BCM2835FBState fb;
BCM2835DMAState dma;
+ qemu_or_irq dma_11_14_irq_orgate;
BCM2835ICState ic;
BCM2835PropertyState property;
BCM2835RngState rng;
Regards,
Phil.
