[edk2-devel] [PATCH v3 2/2] Platform/RaspberryPi: Enable Bluetooth and UART in Windows OS

Sunny Wang Sunny.Wang at arm.com
Mon May 31 13:26:38 UTC 2021 

Hi Mario,

Thanks for checking this.
Yeah, the problem is NO COM port for PL011 UART in Windows IOT’s device manager, so I thought it doesn’t work. If there is no COM port for PL011 UART, how can I check PL011 UART’s functionality? How can I use a telnet tool like PuTTY to send messages from RPi4 to my laptop? How to use SerCx2? Is there a guideline for using PL011 UART on RPi4 with Windows IoT?

As for why I mux both UARTs to the BT chip, I was trying to address your comment “This always assumes that PL011 is used for Bluetooth”. Apparently, it didn’t address your comment. No matter whether I add “PinFunction (Exclusive, PullDown, BCM_ALT5, "\\_SB.GDV0.GPI0<file://_SB.GDV0.GPI0>", 0, ResourceConsumer, , ) { 32, 33 }” or not, the Bluetooth has NOT worked when I configure PL011 UART as the primary serial console. Bluetooth only works when I configure Mini UART as the Primary serial console. I also confirmed that this problem also exists with RPi4 Release FW 1.26 + edk2-platforms-raspberrypi-pl011-bth-noflow.diff in https://github.com/worproject/RPi-Bluetooth-Testing/. Do you have any idea to make the Bluetooth work with configuring PL011 UART as the primary serial console? By the way, it is good to know the loading sequence. Do you know where I can quickly find this information without using WinDbg?


Actually, the original code change (Patch 2/2) is the patch (edk2-platforms-raspberrypi-pl011-bth-noflow.diff) on  https://github.com/worproject/RPi-Bluetooth-Testing/. I’m not familiar with Windows drivers’ behavior, so I had no idea about why we need to change them and couldn’t find more information about the changes’ background either. It looks like you know the details. Could you share with me more information about the background of these changes? At least, I have some questions below:
1.  What is the connection between GPIO 128 and Bluetooth (BT_ON)? Why did we add this line in the beginning? I just removed it by your request and according to the change in worproject/RPi-Bluetooth-Testing/, but I’m still worried about if we did this for some other purposes.
2.  Why do we need to configure GPIO 32 and 33? Is the Bluetooth using GPIO 32 and 33? Or Is Windows OS checking GPIO 32 and 33 for Bluetooth? Where can I find the information?
3.  As for your comment about GPIO 31, I was confused, so I didn’t update anything for addressing this comment. My understanding was that It is intended to override the BCM_ALT2’s default setting from PullLow to PullNone to fack the CTS signal. If we change it to PullLow, it will be used for HW flow control, which is unwanted, isn’t it? What did you want me to change? Could you directly paste the code change you wanted here for my reference?

Moreover, for the changes you want, could you also paste the code change?

Best Regards,
Sunny Wang

From: devel at edk2.groups.io <devel at edk2.groups.io> On Behalf Of Mario Balanica via groups.io
Sent: Monday, May 31, 2021 8:41 PM
To: Sunny Wang <Sunny.Wang at arm.com>
Cc: devel at edk2.groups.io; Samer El-Haj-Mahmoud <Samer.El-Haj-Mahmoud at arm.com>; Sami Mujawar <Sami.Mujawar at arm.com>; Jeremy Linton <Jeremy.Linton at arm.com>; Pete Batard <pete at akeo.ie>; Ard Biesheuvel <ardb+tianocore at kernel.org>
Subject: Re: [edk2-devel] [PATCH v3 2/2] Platform/RaspberryPi: Enable Bluetooth and UART in Windows OS

Hi Sunny,

What issues are you seeing with the PL011 UART in Windows? Last time I checked, it worked fine, and the fact that Bluetooth works also confirms this.
It won't show up as a COM port (like mini UART does) as it's built using SerCx2.

@@ -30,6 +30,12 @@ Device (URT0)
   {
     MEMORY32FIXED (ReadWrite, 0, BCM2836_PL011_UART_LENGTH, RMEM)
     Interrupt (ResourceConsumer, Level, ActiveHigh, Exclusive) { BCM2836_PL011_UART_INTERRUPT }
+
+    PinFunction (Exclusive, PullDown, BCM_ALT3, "\\_SB.GDV0.GPI0<file://_SB.GDV0.GPI0>", 0, ResourceConsumer, , ) { 32, 33 }
+

@@ -79,6 +85,11 @@ Device (URTM)
     // from muxing the pins away.

     // PinFunction (Exclusive, PullDown, BCM_ALT5, "\\_SB.GPI0<file://_SB.GPI0>", 0, ResourceConsumer, , ) { 14, 15 }
+    PinFunction (Exclusive, PullDown, BCM_ALT5, "\\_SB.GDV0.GPI0<file://_SB.GDV0.GPI0>", 0, ResourceConsumer, , ) { 32, 33 }
+

What is the reason for trying to mux both UARTs to the BT chip? If PL011 is used for Bluetooth and the mini UART driver loads after it, wouldn't it mux away the pins and break Bluetooth?




În lun., 31 mai 2021 la 11:23, Sunny Wang <Sunny.Wang at arm.com<mailto:Sunny.Wang at arm.com>> a scris:
This change is based on edk2-platforms-raspberrypi-pl011-bth-noflow.diff
in https://github.com/worproject/RPi-Bluetooth-Testing/ for enabling
Bluetooth and serial port (Mini UART) in Windows IOT.

Note that PL011 UART still doesn't work with Windows 10 IOT with this
change, but PL011 UART works fine with VMware ESXi-Arm Fling v1.3.
Therefore, there should be no issue with PL011 UART related changes,
and we will still need a Windows expert to take a further look in the
future. Making PL011 UART work properly with Windows 10 IOT may require
additional changes to Windows driver or firmware's ACPI table.

Testing Done:
  - Successfully booted Windows Windows 10 IOT (20279.1) on SD (made by WOR) with
    the RPi-Windows-Drivers release ver 0.5 downloaded from
    https://github.com/worproject/RPi-Windows-Drivers/releases
    and checked that both Bluetooth and serial port (Mini UART) can
    work fine.
  - Successfully booted VMware ESXi-Arm Fling v1.3 with only serial
    console connection (PL011 UART).

Cc: Samer El-Haj-Mahmoud <samer.el-haj-mahmoud at arm.com<mailto:samer.el-haj-mahmoud at arm.com>>
Cc: Sami Mujawar <sami.mujawar at arm.com<mailto:sami.mujawar at arm.com>>
Cc: Jeremy Linton <jeremy.linton at arm.com<mailto:jeremy.linton at arm.com>>
Cc: Pete Batard <pete at akeo.ie<mailto:pete at akeo.ie>>
Cc: Ard Biesheuvel <ardb+tianocore at kernel.org<mailto:ardb%2Btianocore at kernel.org>>
Cc: Mario Bălănică <mariobalanica02 at gmail.com<mailto:mariobalanica02 at gmail.com>>
Signed-off-by: Sunny Wang <sunny.wang at arm.com<mailto:sunny.wang at arm.com>>
---
 Platform/RaspberryPi/AcpiTables/Uart.asl | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/Platform/RaspberryPi/AcpiTables/Uart.asl b/Platform/RaspberryPi/AcpiTables/Uart.asl
index bac9d791eb..cb99086d39 100644
--- a/Platform/RaspberryPi/AcpiTables/Uart.asl
+++ b/Platform/RaspberryPi/AcpiTables/Uart.asl
@@ -30,6 +30,12 @@ Device (URT0)
   {
     MEMORY32FIXED (ReadWrite, 0, BCM2836_PL011_UART_LENGTH, RMEM)
     Interrupt (ResourceConsumer, Level, ActiveHigh, Exclusive) { BCM2836_PL011_UART_INTERRUPT }
+
+    PinFunction (Exclusive, PullDown, BCM_ALT3, "\\_SB.GDV0.GPI0<file://_SB.GDV0.GPI0>", 0, ResourceConsumer, , ) { 32, 33 }
+
+    // fake the CTS signal as we don't support HW flow control yet
+    // BCM_ALT2 is set as output (low) by default
+    PinFunction (Exclusive, PullNone, BCM_ALT2, "\\_SB.GDV0.GPI0<file://_SB.GDV0.GPI0>", 0, ResourceConsumer, , ) { 31 }
   })
   Method (_CRS, 0x0, Serialized)
   {
@@ -79,6 +85,11 @@ Device (URTM)
     // from muxing the pins away.

     // PinFunction (Exclusive, PullDown, BCM_ALT5, "\\_SB.GPI0<file://_SB.GPI0>", 0, ResourceConsumer, , ) { 14, 15 }
+    PinFunction (Exclusive, PullDown, BCM_ALT5, "\\_SB.GDV0.GPI0<file://_SB.GDV0.GPI0>", 0, ResourceConsumer, , ) { 32, 33 }
+
+    // fake the CTS signal as we don't support HW flow control yet
+    // BCM_ALT2 is set as output (low) by default
+    PinFunction (Exclusive, PullNone, BCM_ALT2, "\\_SB.GDV0.GPI0<file://_SB.GDV0.GPI0>", 0, ResourceConsumer, , ) { 31 }
   })
   Method (_CRS, 0x0, Serialized)
   {
@@ -143,10 +154,6 @@ Device(BTH0)
       UAR0,          // DescriptorName: creates name
                     //   for offset of resource descriptor
     )                // Vendor data
-    //
-    // RPIQ connection for BT_ON/OFF
-    //
-    GpioIO (Shared, PullUp, 0, 0, IoRestrictionNone, "\\_SB.GDV0.RPIQ<file://_SB.GDV0.RPIQ>", 0, ResourceConsumer, , ) { 128 }
   })

   //
@@ -190,10 +197,6 @@ Device(BTH0)
       UARM,          // DescriptorName: creates name
                     //   for offset of resource descriptor
     )                // Vendor data
-    //
-    // RPIQ connection for BT_ON/OFF
-    //
-    GpioIO (Shared, PullUp, 0, 0, IoRestrictionNone, "\\_SB.GDV0.RPIQ<file://_SB.GDV0.RPIQ>", 0, ResourceConsumer, , ) { 128 }
   })

   Method (_CRS, 0x0, Serialized)
--
2.31.0.windows.1

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