On 23/12/2022 19:45, Manivannan Sadhasivam wrote:
On Fri, Dec 23, 2022 at 07:18:32PM +0200, Dmitry Baryshkov wrote:
On 22/12/2022 15:31, Manivannan Sadhasivam wrote:
Both PCIe0 and PCIe1 controllers are capable of receiving MSIs from
endpoint devices using GIC-ITS MSI controller. Add support for it.
Currently, BDF (0:0.0) and BDF (1:0.0) are enabled and with the
msi-map-mask of 0xff00, all the 32 devices under these two busses can
share the same Device ID.
The GIC-ITS MSI implementation provides an advantage over internal MSI
implementation using Locality-specific Peripheral Interrupts (LPI) that
would allow MSIs to be targeted for each CPU core.
It should be noted that the MSIs for BDF (1:0.0) only works with Device
ID of 0x5980 and 0x5a00. Hence, the IDs are swapped.
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
---
arch/arm64/boot/dts/qcom/sm8450.dtsi | 20 ++++++++++++++------
1 file changed, 14 insertions(+), 6 deletions(-)
diff --git a/arch/arm64/boot/dts/qcom/sm8450.dtsi b/arch/arm64/boot/dts/qcom/sm8450.dtsi
index 570475040d95..c4dd5838fac6 100644
--- a/arch/arm64/boot/dts/qcom/sm8450.dtsi
+++ b/arch/arm64/boot/dts/qcom/sm8450.dtsi
@@ -1733,9 +1733,13 @@ pcie0: pci@1c00000 {
ranges = <0x01000000 0x0 0x60200000 0 0x60200000 0x0 0x100000>,
<0x02000000 0x0 0x60300000 0 0x60300000 0x0 0x3d00000>;
- interrupts = <GIC_SPI 141 IRQ_TYPE_LEVEL_HIGH>;
- interrupt-names = "msi";
- #interrupt-cells = <1>;
+ /*
+ * MSIs for BDF (1:0.0) only works with Device ID 0x5980.
+ * Hence, the IDs are swapped.
+ */
+ msi-map = <0x0 &gic_its 0x5981 0x1>,
+ <0x100 &gic_its 0x5980 0x1>;
This definitely doesn't match what has been used in the downstream.
Yes, I do not know why the downstream Device ID doesn't work. I tried finding
the answer within Qcom but didn't get any answer so far :/ So I just went with
the value that works on multiple boards.
Ugh :-(
Also if I understand correctly this change would prevent us from using
multiple MSI interrupts for the connected device, as the last value of the
0x100 mapping is 0x1, while the vendor kernel uses <0x100 &its 0x5981 0x20>.
Not true. The controller can still support multiple MSIs for the endpoint
devices but the only difference is, it would use the same Device ID for all.
I see, please excuse me then. But don't we have to define multiple MSI
vectors here too?
The Qcom GIC-ITS implementation could only support 32 Device IDs. By specifying
the size of 0x20, a separate Device ID would be used for each devices of bus 1.
But if a PCIe switch is connected and the bus count becomes > 1, then the MSI
allocation would fail because Device IDs are exhausted.
The downstream implementation just assumes that there will be only bus 1 and I
do not want to follow that assumption.
That's why I used "msi-map-mask" property of value "0xff00" here, as that will
allow all the devices under the bus 1 to share the same Device ID. For now I
only mapped bus 1, but extending that in the future for other busses is simple.
Thanks,
Mani
Do you know by chance, why do we differ from the vendor dtsi?
+ msi-map-mask = <0xff00>;
interrupt-map-mask = <0 0 0 0x7>;
interrupt-map = <0 0 0 1 &intc 0 0 0 149 IRQ_TYPE_LEVEL_HIGH>, /* int_a */
<0 0 0 2 &intc 0 0 0 150 IRQ_TYPE_LEVEL_HIGH>, /* int_b */
@@ -1842,9 +1846,13 @@ pcie1: pci@1c08000 {
ranges = <0x01000000 0x0 0x40200000 0 0x40200000 0x0 0x100000>,
<0x02000000 0x0 0x40300000 0 0x40300000 0x0 0x1fd00000>;
- interrupts = <GIC_SPI 307 IRQ_TYPE_LEVEL_HIGH>;
- interrupt-names = "msi";
- #interrupt-cells = <1>;
+ /*
+ * MSIs for BDF (1:0.0) only works with Device ID 0x5a00.
+ * Hence, the IDs are swapped.
+ */
+ msi-map = <0x0 &gic_its 0x5a01 0x1>,
+ <0x100 &gic_its 0x5a00 0x1>;
+ msi-map-mask = <0xff00>;
interrupt-map-mask = <0 0 0 0x7>;
interrupt-map = <0 0 0 1 &intc 0 0 0 434 IRQ_TYPE_LEVEL_HIGH>, /* int_a */
<0 0 0 2 &intc 0 0 0 435 IRQ_TYPE_LEVEL_HIGH>, /* int_b */
--
With best wishes
Dmitry
--
With best wishes
Dmitry
