[PATCH v2 0/9] powerpc: Add support for Microwatt soft-core

[PATCH v2 0/9] powerpc: Add support for Microwatt soft-core

[Paul Mackerras]

This series of patches adds support for the Microwatt soft-core.
Microwatt is an open-source 64-bit Power ISA processor written in VHDL
which targets medium-sized FPGAs such as the Xilinx Artix-7 or the
Lattice ECP5.  Microwatt currently implements the scalar fixed plus
floating-point subset of Power ISA v3.0B plus the radix MMU, but not
logical partitioning (i.e. it does not have hypervisor mode or nested
radix translation).

Changes in v2:

- Dropped the patch that adds support for the PRTBL register, since it
  is not architected.  Instead, I have added support for a 1-entry
  partition table to Microwatt and implemented the PTCR register.

- Updated the device tree.

- Dropped the change to archrandom.h.

- Combined patches 10 and 11 of the previous series into one.

Paul.

 arch/powerpc/Kconfig                      |   2 +-
 arch/powerpc/boot/Makefile                |   4 +
 arch/powerpc/boot/devtree.c               |  59 ++++---
 arch/powerpc/boot/dts/microwatt.dts       | 138 ++++++++++++++++
 arch/powerpc/boot/microwatt.c             |  24 +++
 arch/powerpc/boot/ns16550.c               |   9 +-
 arch/powerpc/boot/wrapper                 |   5 +
 arch/powerpc/configs/microwatt_defconfig  |  98 ++++++++++++
 arch/powerpc/kernel/udbg_16550.c          |  39 +++++
 arch/powerpc/platforms/Kconfig            |   1 +
 arch/powerpc/platforms/Makefile           |   1 +
 arch/powerpc/platforms/microwatt/Kconfig  |  13 ++
 arch/powerpc/platforms/microwatt/Makefile |   1 +
 arch/powerpc/platforms/microwatt/rng.c    |  48 ++++++
 arch/powerpc/platforms/microwatt/setup.c  |  41 +++++
 arch/powerpc/sysdev/xics/Kconfig          |   3 +
 arch/powerpc/sysdev/xics/Makefile         |   1 +
 arch/powerpc/sysdev/xics/ics-native.c     | 257 ++++++++++++++++++++++++++++++
 arch/powerpc/sysdev/xics/xics-common.c    |   2 +
 19 files changed, 718 insertions(+), 28 deletions(-)

[PATCH v2 1/9] powerpc: Add Microwatt platform

[Paul Mackerras]

Microwatt is a FPGA-based implementation of the Power ISA.  It
currently only implements little-endian 64-bit mode, and does
not (yet) support SMP, VMX, VSX or transactional memory.  It has an
optional FPU, and an optional MMU (required for running Linux,
obviously) which implements a configurable radix tree but not
hypervisor mode or nested radix translation.

This adds a new machine type to support FPGA-based SoCs with a
Microwatt core.  CONFIG_MATH_EMULATION can be selected for Microwatt
SOCs which don't have the FPU.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
---
 arch/powerpc/Kconfig                      |  2 +-
 arch/powerpc/platforms/Kconfig            |  1 +
 arch/powerpc/platforms/Makefile           |  1 +
 arch/powerpc/platforms/microwatt/Kconfig  |  9 +++++++++
 arch/powerpc/platforms/microwatt/Makefile |  1 +
 arch/powerpc/platforms/microwatt/setup.c  | 23 +++++++++++++++++++++++
 6 files changed, 36 insertions(+), 1 deletion(-)
 create mode 100644 arch/powerpc/platforms/microwatt/Kconfig
 create mode 100644 arch/powerpc/platforms/microwatt/Makefile
 create mode 100644 arch/powerpc/platforms/microwatt/setup.c

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 386ae12d8523..5ce51c38a346 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -422,7 +422,7 @@ config HUGETLB_PAGE_SIZE_VARIABLE
 
 config MATH_EMULATION
 	bool "Math emulation"
-	depends on 4xx || PPC_8xx || PPC_MPC832x || BOOKE
+	depends on 4xx || PPC_8xx || PPC_MPC832x || BOOKE || PPC_MICROWATT
 	select PPC_FPU_REGS
 	help
 	  Some PowerPC chips designed for embedded applications do not have
diff --git a/arch/powerpc/platforms/Kconfig b/arch/powerpc/platforms/Kconfig
index 7a5e8f4541e3..74be4d06afbf 100644
--- a/arch/powerpc/platforms/Kconfig
+++ b/arch/powerpc/platforms/Kconfig
@@ -20,6 +20,7 @@ source "arch/powerpc/platforms/embedded6xx/Kconfig"
 source "arch/powerpc/platforms/44x/Kconfig"
 source "arch/powerpc/platforms/40x/Kconfig"
 source "arch/powerpc/platforms/amigaone/Kconfig"
+source "arch/powerpc/platforms/microwatt/Kconfig"
 
 config KVM_GUEST
 	bool "KVM Guest support"
diff --git a/arch/powerpc/platforms/Makefile b/arch/powerpc/platforms/Makefile
index 143d4417f6cc..edcb54cdb1a8 100644
--- a/arch/powerpc/platforms/Makefile
+++ b/arch/powerpc/platforms/Makefile
@@ -22,3 +22,4 @@ obj-$(CONFIG_PPC_CELL)		+= cell/
 obj-$(CONFIG_PPC_PS3)		+= ps3/
 obj-$(CONFIG_EMBEDDED6xx)	+= embedded6xx/
 obj-$(CONFIG_AMIGAONE)		+= amigaone/
+obj-$(CONFIG_PPC_MICROWATT)	+= microwatt/
diff --git a/arch/powerpc/platforms/microwatt/Kconfig b/arch/powerpc/platforms/microwatt/Kconfig
new file mode 100644
index 000000000000..3be01e78ce57
--- /dev/null
+++ b/arch/powerpc/platforms/microwatt/Kconfig
@@ -0,0 +1,9 @@
+# SPDX-License-Identifier: GPL-2.0
+config PPC_MICROWATT
+	depends on PPC_BOOK3S_64 && !SMP
+	bool "Microwatt SoC platform"
+	select PPC_XICS
+	select PPC_NATIVE
+	help
+          This option enables support for FPGA-based Microwatt implementations.
+
diff --git a/arch/powerpc/platforms/microwatt/Makefile b/arch/powerpc/platforms/microwatt/Makefile
new file mode 100644
index 000000000000..e6885b3b2ee7
--- /dev/null
+++ b/arch/powerpc/platforms/microwatt/Makefile
@@ -0,0 +1 @@
+obj-y	+= setup.o
diff --git a/arch/powerpc/platforms/microwatt/setup.c b/arch/powerpc/platforms/microwatt/setup.c
new file mode 100644
index 000000000000..d80d52612672
--- /dev/null
+++ b/arch/powerpc/platforms/microwatt/setup.c
@@ -0,0 +1,23 @@
+/*
+ * Microwatt FPGA-based SoC platform setup code.
+ *
+ * Copyright 2020 Paul Mackerras (paulus@ozlabs.org), IBM Corp.
+ */
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/stddef.h>
+#include <linux/init.h>
+#include <asm/machdep.h>
+#include <asm/time.h>
+
+static int __init microwatt_probe(void)
+{
+	return of_machine_is_compatible("microwatt-soc");
+}
+
+define_machine(microwatt) {
+	.name			= "microwatt",
+	.probe			= microwatt_probe,
+	.calibrate_decr		= generic_calibrate_decr,
+};
-- 
2.31.1

Re: [PATCH v2 1/9] powerpc: Add Microwatt platform

[Nicholas Piggin]

Excerpts from Paul Mackerras's message of June 18, 2021 1:43 pm:
> Microwatt is a FPGA-based implementation of the Power ISA.  It
> currently only implements little-endian 64-bit mode, and does
> not (yet) support SMP, VMX, VSX or transactional memory.  It has an
> optional FPU, and an optional MMU (required for running Linux,
> obviously) which implements a configurable radix tree but not
> hypervisor mode or nested radix translation.
> 
> This adds a new machine type to support FPGA-based SoCs with a
> Microwatt core.  CONFIG_MATH_EMULATION can be selected for Microwatt
> SOCs which don't have the FPU.

The only thing I can think of is you may want to select PPC_RADIX and 
other possible things that are required, but that's not a big deal at 
the moment. I have a few kernel size reduction config patches (like 
CONFIG_PPC_HASH) I might be able to upstream now for Microwatt, so I
could do a bit of a pass over the Kconfig stuff at that point.

Reviewed-by: Nicholas Piggin <npiggin@gmail.com>

> 
> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
> ---
>  arch/powerpc/Kconfig                      |  2 +-
>  arch/powerpc/platforms/Kconfig            |  1 +
>  arch/powerpc/platforms/Makefile           |  1 +
>  arch/powerpc/platforms/microwatt/Kconfig  |  9 +++++++++
>  arch/powerpc/platforms/microwatt/Makefile |  1 +
>  arch/powerpc/platforms/microwatt/setup.c  | 23 +++++++++++++++++++++++
>  6 files changed, 36 insertions(+), 1 deletion(-)
>  create mode 100644 arch/powerpc/platforms/microwatt/Kconfig
>  create mode 100644 arch/powerpc/platforms/microwatt/Makefile
>  create mode 100644 arch/powerpc/platforms/microwatt/setup.c
> 
> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
> index 386ae12d8523..5ce51c38a346 100644
> --- a/arch/powerpc/Kconfig
> +++ b/arch/powerpc/Kconfig
> @@ -422,7 +422,7 @@ config HUGETLB_PAGE_SIZE_VARIABLE
>  
>  config MATH_EMULATION
>  	bool "Math emulation"
> -	depends on 4xx || PPC_8xx || PPC_MPC832x || BOOKE
> +	depends on 4xx || PPC_8xx || PPC_MPC832x || BOOKE || PPC_MICROWATT
>  	select PPC_FPU_REGS
>  	help
>  	  Some PowerPC chips designed for embedded applications do not have
> diff --git a/arch/powerpc/platforms/Kconfig b/arch/powerpc/platforms/Kconfig
> index 7a5e8f4541e3..74be4d06afbf 100644
> --- a/arch/powerpc/platforms/Kconfig
> +++ b/arch/powerpc/platforms/Kconfig
> @@ -20,6 +20,7 @@ source "arch/powerpc/platforms/embedded6xx/Kconfig"
>  source "arch/powerpc/platforms/44x/Kconfig"
>  source "arch/powerpc/platforms/40x/Kconfig"
>  source "arch/powerpc/platforms/amigaone/Kconfig"
> +source "arch/powerpc/platforms/microwatt/Kconfig"
>  
>  config KVM_GUEST
>  	bool "KVM Guest support"
> diff --git a/arch/powerpc/platforms/Makefile b/arch/powerpc/platforms/Makefile
> index 143d4417f6cc..edcb54cdb1a8 100644
> --- a/arch/powerpc/platforms/Makefile
> +++ b/arch/powerpc/platforms/Makefile
> @@ -22,3 +22,4 @@ obj-$(CONFIG_PPC_CELL)		+= cell/
>  obj-$(CONFIG_PPC_PS3)		+= ps3/
>  obj-$(CONFIG_EMBEDDED6xx)	+= embedded6xx/
>  obj-$(CONFIG_AMIGAONE)		+= amigaone/
> +obj-$(CONFIG_PPC_MICROWATT)	+= microwatt/
> diff --git a/arch/powerpc/platforms/microwatt/Kconfig b/arch/powerpc/platforms/microwatt/Kconfig
> new file mode 100644
> index 000000000000..3be01e78ce57
> --- /dev/null
> +++ b/arch/powerpc/platforms/microwatt/Kconfig
> @@ -0,0 +1,9 @@
> +# SPDX-License-Identifier: GPL-2.0
> +config PPC_MICROWATT
> +	depends on PPC_BOOK3S_64 && !SMP
> +	bool "Microwatt SoC platform"
> +	select PPC_XICS
> +	select PPC_NATIVE
> +	help
> +          This option enables support for FPGA-based Microwatt implementations.
> +
> diff --git a/arch/powerpc/platforms/microwatt/Makefile b/arch/powerpc/platforms/microwatt/Makefile
> new file mode 100644
> index 000000000000..e6885b3b2ee7
> --- /dev/null
> +++ b/arch/powerpc/platforms/microwatt/Makefile
> @@ -0,0 +1 @@
> +obj-y	+= setup.o
> diff --git a/arch/powerpc/platforms/microwatt/setup.c b/arch/powerpc/platforms/microwatt/setup.c
> new file mode 100644
> index 000000000000..d80d52612672
> --- /dev/null
> +++ b/arch/powerpc/platforms/microwatt/setup.c
> @@ -0,0 +1,23 @@
> +/*
> + * Microwatt FPGA-based SoC platform setup code.
> + *
> + * Copyright 2020 Paul Mackerras (paulus@ozlabs.org), IBM Corp.
> + */
> +
> +#include <linux/types.h>
> +#include <linux/kernel.h>
> +#include <linux/stddef.h>
> +#include <linux/init.h>
> +#include <asm/machdep.h>
> +#include <asm/time.h>
> +
> +static int __init microwatt_probe(void)
> +{
> +	return of_machine_is_compatible("microwatt-soc");
> +}
> +
> +define_machine(microwatt) {
> +	.name			= "microwatt",
> +	.probe			= microwatt_probe,
> +	.calibrate_decr		= generic_calibrate_decr,
> +};
> -- 
> 2.31.1
> 
> 

[PATCH v2 2/9] powerpc: Add Microwatt device tree

[Paul Mackerras]

Microwatt currently runs with MSR[HV] = 0, hence the usable-privilege
properties don't have bit 2 (for HV support) set, and we need the
/chosen/ibm,architecture-vec-5 property.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
---
 arch/powerpc/boot/dts/microwatt.dts | 98 +++++++++++++++++++++++++++++
 1 file changed, 98 insertions(+)
 create mode 100644 arch/powerpc/boot/dts/microwatt.dts

diff --git a/arch/powerpc/boot/dts/microwatt.dts b/arch/powerpc/boot/dts/microwatt.dts
new file mode 100644
index 000000000000..ac264ad3faaf
--- /dev/null
+++ b/arch/powerpc/boot/dts/microwatt.dts
@@ -0,0 +1,98 @@
+/dts-v1/;
+
+/ {
+	#size-cells = <0x02>;
+	#address-cells = <0x02>;
+	model-name = "microwatt";
+	compatible = "microwatt-soc";
+
+	reserved-memory {
+		#size-cells = <0x02>;
+		#address-cells = <0x02>;
+		ranges;
+	};
+
+	memory@0 {
+		device_type = "memory";
+		reg = <0x00000000 0x00000000 0x00000000 0x10000000>;
+	};
+
+	cpus {
+		#size-cells = <0x00>;
+		#address-cells = <0x01>;
+
+		ibm,powerpc-cpu-features {
+			display-name = "Microwatt";
+			isa = <3000>;
+			device_type = "cpu-features";
+			compatible = "ibm,powerpc-cpu-features";
+
+			mmu-radix {
+				isa = <3000>;
+				usable-privilege = <2>;
+			};
+
+			little-endian {
+				isa = <2050>;
+				usable-privilege = <3>;
+				hwcap-bit-nr = <1>;
+			};
+
+			cache-inhibited-large-page {
+				isa = <2040>;
+				usable-privilege = <2>;
+			};
+
+			fixed-point-v3 {
+				isa = <3000>;
+				usable-privilege = <3>;
+			};
+
+			no-execute {
+				isa = <2010>;
+				usable-privilege = <2>;
+			};
+
+			floating-point {
+				hwcap-bit-nr = <27>;
+				isa = <0>;
+				usable-privilege = <3>;
+			};
+		};
+
+		PowerPC,Microwatt@0 {
+			i-cache-sets = <2>;
+			ibm,dec-bits = <64>;
+			reservation-granule-size = <64>;
+			clock-frequency = <100000000>;
+			timebase-frequency = <100000000>;
+			i-tlb-sets = <1>;
+			ibm,ppc-interrupt-server#s = <0>;
+			i-cache-block-size = <64>;
+			d-cache-block-size = <64>;
+			d-cache-sets = <2>;
+			i-tlb-size = <64>;
+			cpu-version = <0x990000>;
+			status = "okay";
+			i-cache-size = <0x1000>;
+			ibm,processor-radix-AP-encodings = <0x0c 0xa0000010 0x20000015 0x4000001e>;
+			tlb-size = <0>;
+			tlb-sets = <0>;
+			device_type = "cpu";
+			d-tlb-size = <128>;
+			d-tlb-sets = <2>;
+			reg = <0>;
+			general-purpose;
+			64-bit;
+			d-cache-size = <0x1000>;
+			ibm,chip-id = <0>;
+		};
+	};
+
+	chosen {
+		bootargs = "";
+		ibm,architecture-vec-5 = [19 00 10 00 00 00 00 00 00 00 00 00 00 00 00 00
+					  00 00 00 00 00 00 00 00 40 00 40];
+	};
+
+};
-- 
2.31.1

Re: [PATCH v2 2/9] powerpc: Add Microwatt device tree

[Segher Boessenkool]

On Fri, Jun 18, 2021 at 01:44:16PM +1000, Paul Mackerras wrote:
> Microwatt currently runs with MSR[HV] = 0,

That isn't compliant though?  If your implementation does not have LPAR
it must set MSR[HV]=1 always.


Segher

Re: [PATCH v2 2/9] powerpc: Add Microwatt device tree

[Paul Mackerras]

On Sat, Jun 19, 2021 at 09:26:16AM -0500, Segher Boessenkool wrote:
> On Fri, Jun 18, 2021 at 01:44:16PM +1000, Paul Mackerras wrote:
> > Microwatt currently runs with MSR[HV] = 0,
> 
> That isn't compliant though?  If your implementation does not have LPAR
> it must set MSR[HV]=1 always.

True - but if I actually do that, Linux starts trying to use hrfid
(for example in masked_Hinterrupt), which Microwatt doesn't have.
Something for Nick to fix. :)

Paul.

Re: [PATCH v2 2/9] powerpc: Add Microwatt device tree

[Segher Boessenkool]

On Sun, Jun 20, 2021 at 10:08:58PM +1000, Paul Mackerras wrote:
> On Sat, Jun 19, 2021 at 09:26:16AM -0500, Segher Boessenkool wrote:
> > On Fri, Jun 18, 2021 at 01:44:16PM +1000, Paul Mackerras wrote:
> > > Microwatt currently runs with MSR[HV] = 0,
> > 
> > That isn't compliant though?  If your implementation does not have LPAR
> > it must set MSR[HV]=1 always.
> 
> True - but if I actually do that, Linux starts trying to use hrfid
> (for example in masked_Hinterrupt), which Microwatt doesn't have.
> Something for Nick to fix. :)

That looks like it needs fixing, yes (it is hard to actually read).  But
one thing you can do to make this Just Work is to make hrfid do exactly
the same as rfid, i.e. decode hrfid (01000 10010) as rfid (00000 10010).
That probably makes things run already, you don't even need to alias
to SPRs HSRRn (01001 1101n) to SRRn (00000 1101n) :-)


Segher

[PATCH v2 3/9] powerpc/microwatt: Populate platform bus from device-tree

[Paul Mackerras]

From: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Just like any other embedded platform.

Add an empty soc node.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
---
 arch/powerpc/boot/dts/microwatt.dts      | 7 +++++++
 arch/powerpc/platforms/microwatt/setup.c | 8 ++++++++
 2 files changed, 15 insertions(+)

diff --git a/arch/powerpc/boot/dts/microwatt.dts b/arch/powerpc/boot/dts/microwatt.dts
index ac264ad3faaf..9b6140c90370 100644
--- a/arch/powerpc/boot/dts/microwatt.dts
+++ b/arch/powerpc/boot/dts/microwatt.dts
@@ -95,4 +95,11 @@ chosen {
 					  00 00 00 00 00 00 00 00 40 00 40];
 	};
 
+	soc@c0000000 {
+		compatible = "simple-bus";
+		#address-cells = <1>;
+		#size-cells = <1>;
+
+		ranges = <0 0 0xc0000000 0x40000000>;
+	};
 };
diff --git a/arch/powerpc/platforms/microwatt/setup.c b/arch/powerpc/platforms/microwatt/setup.c
index d80d52612672..5af4adf881bc 100644
--- a/arch/powerpc/platforms/microwatt/setup.c
+++ b/arch/powerpc/platforms/microwatt/setup.c
@@ -8,6 +8,8 @@
 #include <linux/kernel.h>
 #include <linux/stddef.h>
 #include <linux/init.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
 #include <asm/machdep.h>
 #include <asm/time.h>
 
@@ -16,6 +18,12 @@ static int __init microwatt_probe(void)
 	return of_machine_is_compatible("microwatt-soc");
 }
 
+static int __init microwatt_populate(void)
+{
+	return of_platform_default_populate(NULL, NULL, NULL);
+}
+machine_arch_initcall(microwatt, microwatt_populate);
+
 define_machine(microwatt) {
 	.name			= "microwatt",
 	.probe			= microwatt_probe,
-- 
2.31.1

[PATCH v2 4/9] powerpc/xics: Add a native ICS backend for microwatt

[Paul Mackerras]

From: Benjamin Herrenschmidt <benh@kernel.crashing.org>

This is a simple native ICS backend that matches the layout of
the Microwatt implementation of ICS.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
---
 arch/powerpc/boot/dts/microwatt.dts      |  18 ++
 arch/powerpc/platforms/microwatt/Kconfig |   2 +
 arch/powerpc/platforms/microwatt/setup.c |   8 +
 arch/powerpc/sysdev/xics/Kconfig         |   3 +
 arch/powerpc/sysdev/xics/Makefile        |   1 +
 arch/powerpc/sysdev/xics/ics-native.c    | 257 +++++++++++++++++++++++
 arch/powerpc/sysdev/xics/xics-common.c   |   2 +
 7 files changed, 291 insertions(+)
 create mode 100644 arch/powerpc/sysdev/xics/ics-native.c

diff --git a/arch/powerpc/boot/dts/microwatt.dts b/arch/powerpc/boot/dts/microwatt.dts
index 9b6140c90370..04e5dd92270e 100644
--- a/arch/powerpc/boot/dts/microwatt.dts
+++ b/arch/powerpc/boot/dts/microwatt.dts
@@ -99,7 +99,25 @@ soc@c0000000 {
 		compatible = "simple-bus";
 		#address-cells = <1>;
 		#size-cells = <1>;
+		interrupt-parent = <&ICS>;
 
 		ranges = <0 0 0xc0000000 0x40000000>;
+
+		interrupt-controller@4000 {
+			compatible = "openpower,xics-presentation", "ibm,ppc-xicp";
+			ibm,interrupt-server-ranges = <0x0 0x1>;
+			reg = <0x4000 0x100>;
+		};
+
+		ICS: interrupt-controller@5000 {
+			compatible = "openpower,xics-sources";
+			interrupt-controller;
+			interrupt-ranges = <0x10 0x10>;
+			reg = <0x5000 0x100>;
+			#address-cells = <0>;
+			#size-cells = <0>;
+			#interrupt-cells = <2>;
+		};
+
 	};
 };
diff --git a/arch/powerpc/platforms/microwatt/Kconfig b/arch/powerpc/platforms/microwatt/Kconfig
index 3be01e78ce57..b52c869c0eb8 100644
--- a/arch/powerpc/platforms/microwatt/Kconfig
+++ b/arch/powerpc/platforms/microwatt/Kconfig
@@ -3,6 +3,8 @@ config PPC_MICROWATT
 	depends on PPC_BOOK3S_64 && !SMP
 	bool "Microwatt SoC platform"
 	select PPC_XICS
+	select PPC_ICS_NATIVE
+	select PPC_ICP_NATIVE
 	select PPC_NATIVE
 	help
           This option enables support for FPGA-based Microwatt implementations.
diff --git a/arch/powerpc/platforms/microwatt/setup.c b/arch/powerpc/platforms/microwatt/setup.c
index 5af4adf881bc..1c1b7791fa57 100644
--- a/arch/powerpc/platforms/microwatt/setup.c
+++ b/arch/powerpc/platforms/microwatt/setup.c
@@ -10,8 +10,15 @@
 #include <linux/init.h>
 #include <linux/of.h>
 #include <linux/of_platform.h>
+
 #include <asm/machdep.h>
 #include <asm/time.h>
+#include <asm/xics.h>
+
+static void __init microwatt_init_IRQ(void)
+{
+	xics_init();
+}
 
 static int __init microwatt_probe(void)
 {
@@ -27,5 +34,6 @@ machine_arch_initcall(microwatt, microwatt_populate);
 define_machine(microwatt) {
 	.name			= "microwatt",
 	.probe			= microwatt_probe,
+	.init_IRQ		= microwatt_init_IRQ,
 	.calibrate_decr		= generic_calibrate_decr,
 };
diff --git a/arch/powerpc/sysdev/xics/Kconfig b/arch/powerpc/sysdev/xics/Kconfig
index 304614c920aa..063d9195891f 100644
--- a/arch/powerpc/sysdev/xics/Kconfig
+++ b/arch/powerpc/sysdev/xics/Kconfig
@@ -12,3 +12,6 @@ config PPC_ICP_HV
 
 config PPC_ICS_RTAS
 	def_bool n
+
+config PPC_ICS_NATIVE
+	def_bool n
diff --git a/arch/powerpc/sysdev/xics/Makefile b/arch/powerpc/sysdev/xics/Makefile
index ba1e3117b1c0..747063927c6c 100644
--- a/arch/powerpc/sysdev/xics/Makefile
+++ b/arch/powerpc/sysdev/xics/Makefile
@@ -4,4 +4,5 @@ obj-y				+= xics-common.o
 obj-$(CONFIG_PPC_ICP_NATIVE)	+= icp-native.o
 obj-$(CONFIG_PPC_ICP_HV)	+= icp-hv.o
 obj-$(CONFIG_PPC_ICS_RTAS)	+= ics-rtas.o
+obj-$(CONFIG_PPC_ICS_NATIVE)	+= ics-native.o
 obj-$(CONFIG_PPC_POWERNV)	+= ics-opal.o icp-opal.o
diff --git a/arch/powerpc/sysdev/xics/ics-native.c b/arch/powerpc/sysdev/xics/ics-native.c
new file mode 100644
index 000000000000..d450502f4053
--- /dev/null
+++ b/arch/powerpc/sysdev/xics/ics-native.c
@@ -0,0 +1,257 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * ICS backend for OPAL managed interrupts.
+ *
+ * Copyright 2011 IBM Corp.
+ */
+
+//#define DEBUG
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/irq.h>
+#include <linux/smp.h>
+#include <linux/interrupt.h>
+#include <linux/init.h>
+#include <linux/cpu.h>
+#include <linux/of.h>
+#include <linux/spinlock.h>
+#include <linux/msi.h>
+#include <linux/list.h>
+
+#include <asm/prom.h>
+#include <asm/smp.h>
+#include <asm/machdep.h>
+#include <asm/irq.h>
+#include <asm/errno.h>
+#include <asm/xics.h>
+#include <asm/opal.h>
+#include <asm/firmware.h>
+
+struct ics_native {
+	struct ics		ics;
+	struct device_node	*node;
+	void __iomem    	*base;
+	u32             	ibase;
+	u32             	icount;
+};
+#define to_ics_native(_ics)     container_of(_ics, struct ics_native, ics)
+
+static void __iomem *ics_native_xive(struct ics_native *in, unsigned int vec)
+{
+	return in->base + 0x800 + ((vec - in->ibase) << 2);
+}
+
+static void ics_native_unmask_irq(struct irq_data *d)
+{
+	unsigned int vec = (unsigned int)irqd_to_hwirq(d);
+	struct ics *ics = irq_data_get_irq_chip_data(d);
+	struct ics_native *in = to_ics_native(ics);
+	unsigned int server;
+
+	pr_devel("ics-native: unmask virq %d [hw 0x%x]\n", d->irq, vec);
+
+	if (vec < in->ibase || vec >= (in->ibase + in->icount))
+		return;
+
+	server = xics_get_irq_server(d->irq, irq_data_get_affinity_mask(d), 0);
+	out_be32(ics_native_xive(in, vec), (server << 8) | DEFAULT_PRIORITY);
+}
+
+static unsigned int ics_native_startup(struct irq_data *d)
+{
+#ifdef CONFIG_PCI_MSI
+	/*
+	 * The generic MSI code returns with the interrupt disabled on the
+	 * card, using the MSI mask bits. Firmware doesn't appear to unmask
+	 * at that level, so we do it here by hand.
+	 */
+	if (irq_data_get_msi_desc(d))
+		pci_msi_unmask_irq(d);
+#endif
+
+	/* unmask it */
+	ics_native_unmask_irq(d);
+	return 0;
+}
+
+static void ics_native_do_mask(struct ics_native *in, unsigned int vec)
+{
+	out_be32(ics_native_xive(in, vec), 0xff);
+}
+
+static void ics_native_mask_irq(struct irq_data *d)
+{
+	unsigned int vec = (unsigned int)irqd_to_hwirq(d);
+	struct ics *ics = irq_data_get_irq_chip_data(d);
+	struct ics_native *in = to_ics_native(ics);
+
+	pr_devel("ics-native: mask virq %d [hw 0x%x]\n", d->irq, vec);
+
+	if (vec < in->ibase || vec >= (in->ibase + in->icount))
+		return;
+	ics_native_do_mask(in, vec);
+}
+
+static int ics_native_set_affinity(struct irq_data *d,
+				   const struct cpumask *cpumask,
+				   bool force)
+{
+	unsigned int vec = (unsigned int)irqd_to_hwirq(d);
+	struct ics *ics = irq_data_get_irq_chip_data(d);
+	struct ics_native *in = to_ics_native(ics);
+	int server;
+	u32 xive;
+
+	if (vec < in->ibase || vec >= (in->ibase + in->icount))
+		return -EINVAL;
+
+	server = xics_get_irq_server(d->irq, cpumask, 1);
+	if (server == -1) {
+		pr_warn("%s: No online cpus in the mask %*pb for irq %d\n",
+			__func__, cpumask_pr_args(cpumask), d->irq);
+		return -1;
+	}
+
+	xive = in_be32(ics_native_xive(in, vec));
+	xive = (xive & 0xff) | (server << 8);
+	out_be32(ics_native_xive(in, vec), xive);
+
+	return IRQ_SET_MASK_OK;
+}
+
+static struct irq_chip ics_native_irq_chip = {
+	.name = "ICS",
+	.irq_startup		= ics_native_startup,
+	.irq_mask		= ics_native_mask_irq,
+	.irq_unmask		= ics_native_unmask_irq,
+	.irq_eoi		= NULL, /* Patched at init time */
+	.irq_set_affinity 	= ics_native_set_affinity,
+	.irq_set_type		= xics_set_irq_type,
+	.irq_retrigger		= xics_retrigger,
+};
+
+static int ics_native_map(struct ics *ics, unsigned int virq)
+{
+	unsigned int vec = (unsigned int)virq_to_hw(virq);
+	struct ics_native *in = to_ics_native(ics);
+
+	pr_devel("%s: vec=0x%x\n", __func__, vec);
+
+	if (vec < in->ibase || vec >= (in->ibase + in->icount))
+		return -EINVAL;
+
+	irq_set_chip_and_handler(virq, &ics_native_irq_chip, handle_fasteoi_irq);
+	irq_set_chip_data(virq, ics);
+
+	return 0;
+}
+
+static void ics_native_mask_unknown(struct ics *ics, unsigned long vec)
+{
+	struct ics_native *in = to_ics_native(ics);
+
+	if (vec < in->ibase || vec >= (in->ibase + in->icount))
+		return;
+
+	ics_native_do_mask(in, vec);
+}
+
+static long ics_native_get_server(struct ics *ics, unsigned long vec)
+{
+	struct ics_native *in = to_ics_native(ics);
+	u32 xive;
+
+	if (vec < in->ibase || vec >= (in->ibase + in->icount))
+		return -EINVAL;
+
+	xive = in_be32(ics_native_xive(in, vec));
+	return (xive >> 8) & 0xfff;
+}
+
+static int ics_native_host_match(struct ics *ics, struct device_node *node)
+{
+	struct ics_native *in = to_ics_native(ics);
+
+	return in->node == node;
+}
+
+static struct ics ics_native_template = {
+	.map		= ics_native_map,
+	.mask_unknown	= ics_native_mask_unknown,
+	.get_server	= ics_native_get_server,
+	.host_match	= ics_native_host_match,
+};
+
+static int __init ics_native_add_one(struct device_node *np)
+{
+	struct ics_native *ics;
+	u32 ranges[2];
+	int rc, count;
+
+	ics = kzalloc(sizeof(struct ics_native), GFP_KERNEL);
+	if (!ics)
+		return -ENOMEM;
+	ics->node = of_node_get(np);
+	memcpy(&ics->ics, &ics_native_template, sizeof(struct ics));
+
+	ics->base = of_iomap(np, 0);
+	if (!ics->base) {
+		pr_err("Failed to map %pOFP\n", np);
+		rc = -ENOMEM;
+		goto fail;
+	}
+
+	count = of_property_count_u32_elems(np, "interrupt-ranges");
+	if (count < 2 || count & 1) {
+		pr_err("Failed to read interrupt-ranges of %pOFP\n", np);
+		rc = -EINVAL;
+		goto fail;
+	}
+	if (count > 2) {
+		pr_warn("ICS %pOFP has %d ranges, only one supported\n",
+			np, count >> 1);
+	}
+	rc = of_property_read_u32_array(np, "interrupt-ranges",
+					ranges, 2);
+	if (rc) {
+		pr_err("Failed to read interrupt-ranges of %pOFP\n", np);
+		goto fail;
+	}
+	ics->ibase = ranges[0];
+	ics->icount = ranges[1];
+
+	pr_info("ICS native initialized for sources %d..%d\n",
+		ics->ibase, ics->ibase + ics->icount - 1);
+
+	/* Register ourselves */
+	xics_register_ics(&ics->ics);
+
+	return 0;
+fail:
+	of_node_put(ics->node);
+	kfree(ics);
+	return rc;
+}
+
+int __init ics_native_init(void)
+{
+	struct device_node *ics;
+	bool found_one = false;
+
+	/* We need to patch our irq chip's EOI to point to the
+	 * right ICP
+	 */
+	ics_native_irq_chip.irq_eoi = icp_ops->eoi;
+
+	/* Find native ICS in the device-tree */
+	for_each_compatible_node(ics, NULL, "openpower,xics-sources") {
+		if (ics_native_add_one(ics) == 0)
+			found_one = true;
+	}
+
+	if (found_one)
+		pr_info("ICS native backend registered\n");
+
+	return found_one ? 0 : -ENODEV;
+}
diff --git a/arch/powerpc/sysdev/xics/xics-common.c b/arch/powerpc/sysdev/xics/xics-common.c
index 7e4305c01bac..de41ab91f793 100644
--- a/arch/powerpc/sysdev/xics/xics-common.c
+++ b/arch/powerpc/sysdev/xics/xics-common.c
@@ -476,6 +476,8 @@ void __init xics_init(void)
 	rc = ics_rtas_init();
 	if (rc < 0)
 		rc = ics_opal_init();
+	if (rc < 0)
+		rc = ics_native_init();
 	if (rc < 0)
 		pr_warn("XICS: Cannot find a Source Controller !\n");
 
-- 
2.31.1

[PATCH v2 5/9] powerpc/microwatt: Use standard 16550 UART for console

[Paul Mackerras]

From: Benjamin Herrenschmidt <benh@kernel.crashing.org>

This adds support to the Microwatt platform to use the standard
16550-style UART which available in the standalone Microwatt FPGA.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
---
 arch/powerpc/boot/dts/microwatt.dts      | 27 ++++++++++++----
 arch/powerpc/kernel/udbg_16550.c         | 39 ++++++++++++++++++++++++
 arch/powerpc/platforms/microwatt/Kconfig |  1 +
 arch/powerpc/platforms/microwatt/setup.c |  2 ++
 4 files changed, 63 insertions(+), 6 deletions(-)

diff --git a/arch/powerpc/boot/dts/microwatt.dts b/arch/powerpc/boot/dts/microwatt.dts
index 04e5dd92270e..974abbdda249 100644
--- a/arch/powerpc/boot/dts/microwatt.dts
+++ b/arch/powerpc/boot/dts/microwatt.dts
@@ -6,6 +6,10 @@ / {
 	model-name = "microwatt";
 	compatible = "microwatt-soc";
 
+	aliases {
+		serial0 = &UART0;
+	};
+
 	reserved-memory {
 		#size-cells = <0x02>;
 		#address-cells = <0x02>;
@@ -89,12 +93,6 @@ PowerPC,Microwatt@0 {
 		};
 	};
 
-	chosen {
-		bootargs = "";
-		ibm,architecture-vec-5 = [19 00 10 00 00 00 00 00 00 00 00 00 00 00 00 00
-					  00 00 00 00 00 00 00 00 40 00 40];
-	};
-
 	soc@c0000000 {
 		compatible = "simple-bus";
 		#address-cells = <1>;
@@ -119,5 +117,22 @@ ICS: interrupt-controller@5000 {
 			#interrupt-cells = <2>;
 		};
 
+		UART0: serial@2000 {
+			device_type = "serial";
+			compatible = "ns16550";
+			reg = <0x2000 0x8>;
+			clock-frequency = <100000000>;
+			current-speed = <115200>;
+			reg-shift = <2>;
+			fifo-size = <16>;
+			interrupts = <0x10 0x1>;
+		};
+	};
+
+	chosen {
+		bootargs = "";
+		ibm,architecture-vec-5 = [19 00 10 00 00 00 00 00 00 00 00 00 00 00 00 00
+					  00 00 00 00 00 00 00 00 40 00 40];
+		stdout-path = &UART0;
 	};
 };
diff --git a/arch/powerpc/kernel/udbg_16550.c b/arch/powerpc/kernel/udbg_16550.c
index 9356b60d6030..8513aa49614e 100644
--- a/arch/powerpc/kernel/udbg_16550.c
+++ b/arch/powerpc/kernel/udbg_16550.c
@@ -296,3 +296,42 @@ void __init udbg_init_40x_realmode(void)
 }
 
 #endif /* CONFIG_PPC_EARLY_DEBUG_40x */
+
+#ifdef CONFIG_PPC_EARLY_DEBUG_MICROWATT
+
+#define UDBG_UART_MW_ADDR	((void __iomem *)0xc0002000)
+
+static u8 udbg_uart_in_isa300_rm(unsigned int reg)
+{
+	uint64_t msr = mfmsr();
+	uint8_t  c;
+
+	mtmsr(msr & ~(MSR_EE|MSR_DR));
+	isync();
+	eieio();
+	c = __raw_rm_readb(UDBG_UART_MW_ADDR + (reg << 2));
+	mtmsr(msr);
+	isync();
+	return c;
+}
+
+static void udbg_uart_out_isa300_rm(unsigned int reg, u8 val)
+{
+	uint64_t msr = mfmsr();
+
+	mtmsr(msr & ~(MSR_EE|MSR_DR));
+	isync();
+	eieio();
+	__raw_rm_writeb(val, UDBG_UART_MW_ADDR + (reg << 2));
+	mtmsr(msr);
+	isync();
+}
+
+void __init udbg_init_debug_microwatt(void)
+{
+	udbg_uart_in = udbg_uart_in_isa300_rm;
+	udbg_uart_out = udbg_uart_out_isa300_rm;
+	udbg_use_uart();
+}
+
+#endif /* CONFIG_PPC_EARLY_DEBUG_MICROWATT */
diff --git a/arch/powerpc/platforms/microwatt/Kconfig b/arch/powerpc/platforms/microwatt/Kconfig
index b52c869c0eb8..50ed0cedb5f1 100644
--- a/arch/powerpc/platforms/microwatt/Kconfig
+++ b/arch/powerpc/platforms/microwatt/Kconfig
@@ -6,6 +6,7 @@ config PPC_MICROWATT
 	select PPC_ICS_NATIVE
 	select PPC_ICP_NATIVE
 	select PPC_NATIVE
+	select PPC_UDBG_16550
 	help
           This option enables support for FPGA-based Microwatt implementations.
 
diff --git a/arch/powerpc/platforms/microwatt/setup.c b/arch/powerpc/platforms/microwatt/setup.c
index 1c1b7791fa57..0b02603bdb74 100644
--- a/arch/powerpc/platforms/microwatt/setup.c
+++ b/arch/powerpc/platforms/microwatt/setup.c
@@ -14,6 +14,7 @@
 #include <asm/machdep.h>
 #include <asm/time.h>
 #include <asm/xics.h>
+#include <asm/udbg.h>
 
 static void __init microwatt_init_IRQ(void)
 {
@@ -35,5 +36,6 @@ define_machine(microwatt) {
 	.name			= "microwatt",
 	.probe			= microwatt_probe,
 	.init_IRQ		= microwatt_init_IRQ,
+	.progress		= udbg_progress,
 	.calibrate_decr		= generic_calibrate_decr,
 };
-- 
2.31.1

Re: [PATCH v2 5/9] powerpc/microwatt: Use standard 16550 UART for console

[Nicholas Piggin]

Excerpts from Paul Mackerras's message of June 18, 2021 1:46 pm:
> From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> 
> This adds support to the Microwatt platform to use the standard
> 16550-style UART which available in the standalone Microwatt FPGA.
> 
> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
> ---
>  arch/powerpc/boot/dts/microwatt.dts      | 27 ++++++++++++----
>  arch/powerpc/kernel/udbg_16550.c         | 39 ++++++++++++++++++++++++
>  arch/powerpc/platforms/microwatt/Kconfig |  1 +
>  arch/powerpc/platforms/microwatt/setup.c |  2 ++
>  4 files changed, 63 insertions(+), 6 deletions(-)
> 
> diff --git a/arch/powerpc/boot/dts/microwatt.dts b/arch/powerpc/boot/dts/microwatt.dts
> index 04e5dd92270e..974abbdda249 100644
> --- a/arch/powerpc/boot/dts/microwatt.dts
> +++ b/arch/powerpc/boot/dts/microwatt.dts
> @@ -6,6 +6,10 @@ / {
>  	model-name = "microwatt";
>  	compatible = "microwatt-soc";
>  
> +	aliases {
> +		serial0 = &UART0;
> +	};
> +
>  	reserved-memory {
>  		#size-cells = <0x02>;
>  		#address-cells = <0x02>;
> @@ -89,12 +93,6 @@ PowerPC,Microwatt@0 {
>  		};
>  	};
>  
> -	chosen {
> -		bootargs = "";
> -		ibm,architecture-vec-5 = [19 00 10 00 00 00 00 00 00 00 00 00 00 00 00 00
> -					  00 00 00 00 00 00 00 00 40 00 40];
> -	};
> -
>  	soc@c0000000 {
>  		compatible = "simple-bus";
>  		#address-cells = <1>;
> @@ -119,5 +117,22 @@ ICS: interrupt-controller@5000 {
>  			#interrupt-cells = <2>;
>  		};
>  
> +		UART0: serial@2000 {
> +			device_type = "serial";
> +			compatible = "ns16550";
> +			reg = <0x2000 0x8>;
> +			clock-frequency = <100000000>;
> +			current-speed = <115200>;
> +			reg-shift = <2>;
> +			fifo-size = <16>;
> +			interrupts = <0x10 0x1>;
> +		};
> +	};
> +
> +	chosen {
> +		bootargs = "";
> +		ibm,architecture-vec-5 = [19 00 10 00 00 00 00 00 00 00 00 00 00 00 00 00
> +					  00 00 00 00 00 00 00 00 40 00 40];
> +		stdout-path = &UART0;
>  	};
>  };
> diff --git a/arch/powerpc/kernel/udbg_16550.c b/arch/powerpc/kernel/udbg_16550.c
> index 9356b60d6030..8513aa49614e 100644
> --- a/arch/powerpc/kernel/udbg_16550.c
> +++ b/arch/powerpc/kernel/udbg_16550.c
> @@ -296,3 +296,42 @@ void __init udbg_init_40x_realmode(void)
>  }
>  
>  #endif /* CONFIG_PPC_EARLY_DEBUG_40x */
> +
> +#ifdef CONFIG_PPC_EARLY_DEBUG_MICROWATT
> +
> +#define UDBG_UART_MW_ADDR	((void __iomem *)0xc0002000)
> +
> +static u8 udbg_uart_in_isa300_rm(unsigned int reg)
> +{
> +	uint64_t msr = mfmsr();
> +	uint8_t  c;
> +
> +	mtmsr(msr & ~(MSR_EE|MSR_DR));
> +	isync();
> +	eieio();
> +	c = __raw_rm_readb(UDBG_UART_MW_ADDR + (reg << 2));
> +	mtmsr(msr);
> +	isync();
> +	return c;
> +}

Why is realmode required? No cache inhibited mappings yet?

mtmsrd with L=0 is defined to be context synchronizing in isa 3, so I 
don't think the isync would be required. There is a bit of code around 
arch/powerpc that does this, maybe it used to be needed or some other
implementations needed it?

That's just for my curiosity, it doesn't really hurt to have them
there.

Thanks,
Nick

Re: [PATCH v2 5/9] powerpc/microwatt: Use standard 16550 UART for console

[Paul Mackerras]

On Fri, Jun 18, 2021 at 05:40:40PM +1000, Nicholas Piggin wrote:
> Excerpts from Paul Mackerras's message of June 18, 2021 1:46 pm:
> > From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> > 
> > This adds support to the Microwatt platform to use the standard
> > 16550-style UART which available in the standalone Microwatt FPGA.
> > 
> > Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> > Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
...
> > +#ifdef CONFIG_PPC_EARLY_DEBUG_MICROWATT
> > +
> > +#define UDBG_UART_MW_ADDR	((void __iomem *)0xc0002000)
> > +
> > +static u8 udbg_uart_in_isa300_rm(unsigned int reg)
> > +{
> > +	uint64_t msr = mfmsr();
> > +	uint8_t  c;
> > +
> > +	mtmsr(msr & ~(MSR_EE|MSR_DR));
> > +	isync();
> > +	eieio();
> > +	c = __raw_rm_readb(UDBG_UART_MW_ADDR + (reg << 2));
> > +	mtmsr(msr);
> > +	isync();
> > +	return c;
> > +}
> 
> Why is realmode required? No cache inhibited mappings yet?

Because it's EARLY debug, for use in the very early stages of boot
when the kernel's radix tree may or may not have been initialized.
The easiest way to make a function that works correctly whether or not
the radix tree has been initialized and the MMU turned on is to
temporarily turn off the MMU for data accesses and use lbzcix/stbcix
(which Microwatt has, even though it doesn't implement hypervisor
mode).

(I don't know which "yet" you meant - "yet" in the process of booting a
kernel, or "yet" in the process of Microwatt's development?  Microwatt
certainly does have cache-inhibited mappings and has done since the
MMU was first introduced.)

In fact the defconfig I add later in the series doesn't enable
CONFIG_PPC_EARLY_DEBUG_MICROWATT, but it's there if it's needed for
debugging.

> mtmsrd with L=0 is defined to be context synchronizing in isa 3, so I 
> don't think the isync would be required. There is a bit of code around 
> arch/powerpc that does this, maybe it used to be needed or some other
> implementations needed it?
> 
> That's just for my curiosity, it doesn't really hurt to have them
> there.

Right, and in fact mtmsrd is marked as a single-issue instruction in
Microwatt, so it should work with no isyncs or eieios.  Presumably Ben
copied the isync/eieio pattern from somewhere else.

Paul.

Re: [PATCH v2 5/9] powerpc/microwatt: Use standard 16550 UART for console

[Nicholas Piggin]

Excerpts from Paul Mackerras's message of June 18, 2021 10:12 pm:
> On Fri, Jun 18, 2021 at 05:40:40PM +1000, Nicholas Piggin wrote:
>> Excerpts from Paul Mackerras's message of June 18, 2021 1:46 pm:
>> > From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
>> > 
>> > This adds support to the Microwatt platform to use the standard
>> > 16550-style UART which available in the standalone Microwatt FPGA.
>> > 
>> > Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
>> > Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
> ...
>> > +#ifdef CONFIG_PPC_EARLY_DEBUG_MICROWATT
>> > +
>> > +#define UDBG_UART_MW_ADDR	((void __iomem *)0xc0002000)
>> > +
>> > +static u8 udbg_uart_in_isa300_rm(unsigned int reg)
>> > +{
>> > +	uint64_t msr = mfmsr();
>> > +	uint8_t  c;
>> > +
>> > +	mtmsr(msr & ~(MSR_EE|MSR_DR));
>> > +	isync();
>> > +	eieio();
>> > +	c = __raw_rm_readb(UDBG_UART_MW_ADDR + (reg << 2));
>> > +	mtmsr(msr);
>> > +	isync();
>> > +	return c;
>> > +}
>> 
>> Why is realmode required? No cache inhibited mappings yet?
> 
> Because it's EARLY debug, for use in the very early stages of boot
> when the kernel's radix tree may or may not have been initialized.
> The easiest way to make a function that works correctly whether or not
> the radix tree has been initialized and the MMU turned on is to
> temporarily turn off the MMU for data accesses and use lbzcix/stbcix

Ah makes sense.

> (which Microwatt has, even though it doesn't implement hypervisor
> mode).
> 
> (I don't know which "yet" you meant - "yet" in the process of booting a
> kernel, or "yet" in the process of Microwatt's development?  Microwatt
> certainly does have cache-inhibited mappings and has done since the
> MMU was first introduced.)

I did mean mappings to the UART, but good to get both answers :D

> 
> In fact the defconfig I add later in the series doesn't enable
> CONFIG_PPC_EARLY_DEBUG_MICROWATT, but it's there if it's needed for
> debugging.
> 
>> mtmsrd with L=0 is defined to be context synchronizing in isa 3, so I 
>> don't think the isync would be required. There is a bit of code around 
>> arch/powerpc that does this, maybe it used to be needed or some other
>> implementations needed it?
>> 
>> That's just for my curiosity, it doesn't really hurt to have them
>> there.
> 
> Right, and in fact mtmsrd is marked as a single-issue instruction in
> Microwatt, so it should work with no isyncs or eieios.  Presumably Ben
> copied the isync/eieio pattern from somewhere else.

Makes sense. Well I don't have any objection to the series.

Thanks,
Nick

Re: [PATCH v2 5/9] powerpc/microwatt: Use standard 16550 UART for console

[Christophe Leroy]

Le 18/06/2021 à 05:46, Paul Mackerras a écrit :
> From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> 
> This adds support to the Microwatt platform to use the standard
> 16550-style UART which available in the standalone Microwatt FPGA.
> 
> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
> ---
>   arch/powerpc/boot/dts/microwatt.dts      | 27 ++++++++++++----
>   arch/powerpc/kernel/udbg_16550.c         | 39 ++++++++++++++++++++++++
>   arch/powerpc/platforms/microwatt/Kconfig |  1 +
>   arch/powerpc/platforms/microwatt/setup.c |  2 ++
>   4 files changed, 63 insertions(+), 6 deletions(-)
> 
> diff --git a/arch/powerpc/boot/dts/microwatt.dts b/arch/powerpc/boot/dts/microwatt.dts
> index 04e5dd92270e..974abbdda249 100644
> --- a/arch/powerpc/boot/dts/microwatt.dts
> +++ b/arch/powerpc/boot/dts/microwatt.dts
> @@ -6,6 +6,10 @@ / {
>   	model-name = "microwatt";
>   	compatible = "microwatt-soc";
>   
> +	aliases {
> +		serial0 = &UART0;
> +	};
> +
>   	reserved-memory {
>   		#size-cells = <0x02>;
>   		#address-cells = <0x02>;
> @@ -89,12 +93,6 @@ PowerPC,Microwatt@0 {
>   		};
>   	};
>   
> -	chosen {
> -		bootargs = "";
> -		ibm,architecture-vec-5 = [19 00 10 00 00 00 00 00 00 00 00 00 00 00 00 00
> -					  00 00 00 00 00 00 00 00 40 00 40];
> -	};
> -
>   	soc@c0000000 {
>   		compatible = "simple-bus";
>   		#address-cells = <1>;
> @@ -119,5 +117,22 @@ ICS: interrupt-controller@5000 {
>   			#interrupt-cells = <2>;
>   		};
>   
> +		UART0: serial@2000 {
> +			device_type = "serial";
> +			compatible = "ns16550";
> +			reg = <0x2000 0x8>;
> +			clock-frequency = <100000000>;
> +			current-speed = <115200>;
> +			reg-shift = <2>;
> +			fifo-size = <16>;
> +			interrupts = <0x10 0x1>;
> +		};
> +	};
> +
> +	chosen {
> +		bootargs = "";
> +		ibm,architecture-vec-5 = [19 00 10 00 00 00 00 00 00 00 00 00 00 00 00 00
> +					  00 00 00 00 00 00 00 00 40 00 40];
> +		stdout-path = &UART0;
>   	};
>   };
> diff --git a/arch/powerpc/kernel/udbg_16550.c b/arch/powerpc/kernel/udbg_16550.c
> index 9356b60d6030..8513aa49614e 100644
> --- a/arch/powerpc/kernel/udbg_16550.c
> +++ b/arch/powerpc/kernel/udbg_16550.c
> @@ -296,3 +296,42 @@ void __init udbg_init_40x_realmode(void)
>   }
>   
>   #endif /* CONFIG_PPC_EARLY_DEBUG_40x */
> +
> +#ifdef CONFIG_PPC_EARLY_DEBUG_MICROWATT
> +
> +#define UDBG_UART_MW_ADDR	((void __iomem *)0xc0002000)
> +
> +static u8 udbg_uart_in_isa300_rm(unsigned int reg)
> +{
> +	uint64_t msr = mfmsr();
> +	uint8_t  c;
> +
> +	mtmsr(msr & ~(MSR_EE|MSR_DR));
> +	isync();
> +	eieio();
> +	c = __raw_rm_readb(UDBG_UART_MW_ADDR + (reg << 2));
> +	mtmsr(msr);
> +	isync();
> +	return c;
> +}

How do you make sure that GCC won't emit any access to the stack between the two mtmsr() ?

What about using real_205_readb() and real_205_writeb() instead ?

> +
> +static void udbg_uart_out_isa300_rm(unsigned int reg, u8 val)
> +{
> +	uint64_t msr = mfmsr();
> +
> +	mtmsr(msr & ~(MSR_EE|MSR_DR));
> +	isync();
> +	eieio();
> +	__raw_rm_writeb(val, UDBG_UART_MW_ADDR + (reg << 2));
> +	mtmsr(msr);
> +	isync();
> +}
> +
> +void __init udbg_init_debug_microwatt(void)
> +{
> +	udbg_uart_in = udbg_uart_in_isa300_rm;
> +	udbg_uart_out = udbg_uart_out_isa300_rm;
> +	udbg_use_uart();
> +}
> +
> +#endif /* CONFIG_PPC_EARLY_DEBUG_MICROWATT */
> diff --git a/arch/powerpc/platforms/microwatt/Kconfig b/arch/powerpc/platforms/microwatt/Kconfig
> index b52c869c0eb8..50ed0cedb5f1 100644
> --- a/arch/powerpc/platforms/microwatt/Kconfig
> +++ b/arch/powerpc/platforms/microwatt/Kconfig
> @@ -6,6 +6,7 @@ config PPC_MICROWATT
>   	select PPC_ICS_NATIVE
>   	select PPC_ICP_NATIVE
>   	select PPC_NATIVE
> +	select PPC_UDBG_16550
>   	help
>             This option enables support for FPGA-based Microwatt implementations.
>   
> diff --git a/arch/powerpc/platforms/microwatt/setup.c b/arch/powerpc/platforms/microwatt/setup.c
> index 1c1b7791fa57..0b02603bdb74 100644
> --- a/arch/powerpc/platforms/microwatt/setup.c
> +++ b/arch/powerpc/platforms/microwatt/setup.c
> @@ -14,6 +14,7 @@
>   #include <asm/machdep.h>
>   #include <asm/time.h>
>   #include <asm/xics.h>
> +#include <asm/udbg.h>
>   
>   static void __init microwatt_init_IRQ(void)
>   {
> @@ -35,5 +36,6 @@ define_machine(microwatt) {
>   	.name			= "microwatt",
>   	.probe			= microwatt_probe,
>   	.init_IRQ		= microwatt_init_IRQ,
> +	.progress		= udbg_progress,
>   	.calibrate_decr		= generic_calibrate_decr,
>   };
> 

Re: [PATCH v2 5/9] powerpc/microwatt: Use standard 16550 UART for console

[Segher Boessenkool]

On Thu, Aug 12, 2021 at 03:14:44PM +0200, Christophe Leroy wrote:
> Le 18/06/2021 à 05:46, Paul Mackerras a écrit :
> >+static u8 udbg_uart_in_isa300_rm(unsigned int reg)
> >+{
> >+	uint64_t msr = mfmsr();
> >+	uint8_t  c;
> >+
> >+	mtmsr(msr & ~(MSR_EE|MSR_DR));
> >+	isync();
> >+	eieio();
> >+	c = __raw_rm_readb(UDBG_UART_MW_ADDR + (reg << 2));
> >+	mtmsr(msr);
> >+	isync();
> >+	return c;
> >+}
> 
> How do you make sure that GCC won't emit any access to the stack between 
> the two mtmsr() ?

The mtmsr are asm with a memory clobber so nothing will be moved between
these, and it is very unlikely anything will sprout up here out of
nothing.  But yes, this whole thing should be written as real asm (or as
one huge inline asm, but ugh).


Segher

[PATCH v2 6/9] powerpc/microwatt: Add support for hardware random number generator

[Paul Mackerras]

Microwatt's hardware RNG is accessed using the DARN instruction.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
---
 arch/powerpc/platforms/microwatt/Kconfig  |  1 +
 arch/powerpc/platforms/microwatt/Makefile |  2 +-
 arch/powerpc/platforms/microwatt/rng.c    | 48 +++++++++++++++++++++++
 3 files changed, 50 insertions(+), 1 deletion(-)
 create mode 100644 arch/powerpc/platforms/microwatt/rng.c

diff --git a/arch/powerpc/platforms/microwatt/Kconfig b/arch/powerpc/platforms/microwatt/Kconfig
index 50ed0cedb5f1..8f6a81978461 100644
--- a/arch/powerpc/platforms/microwatt/Kconfig
+++ b/arch/powerpc/platforms/microwatt/Kconfig
@@ -7,6 +7,7 @@ config PPC_MICROWATT
 	select PPC_ICP_NATIVE
 	select PPC_NATIVE
 	select PPC_UDBG_16550
+	select ARCH_RANDOM
 	help
           This option enables support for FPGA-based Microwatt implementations.
 
diff --git a/arch/powerpc/platforms/microwatt/Makefile b/arch/powerpc/platforms/microwatt/Makefile
index e6885b3b2ee7..116d6d3ad3f0 100644
--- a/arch/powerpc/platforms/microwatt/Makefile
+++ b/arch/powerpc/platforms/microwatt/Makefile
@@ -1 +1 @@
-obj-y	+= setup.o
+obj-y	+= setup.o rng.o
diff --git a/arch/powerpc/platforms/microwatt/rng.c b/arch/powerpc/platforms/microwatt/rng.c
new file mode 100644
index 000000000000..3d8ee6eb7dad
--- /dev/null
+++ b/arch/powerpc/platforms/microwatt/rng.c
@@ -0,0 +1,48 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Derived from arch/powerpc/platforms/powernv/rng.c, which is:
+ * Copyright 2013, Michael Ellerman, IBM Corporation.
+ */
+
+#define pr_fmt(fmt)	"microwatt-rng: " fmt
+
+#include <linux/kernel.h>
+#include <linux/smp.h>
+#include <asm/archrandom.h>
+#include <asm/cputable.h>
+#include <asm/machdep.h>
+
+#define DARN_ERR 0xFFFFFFFFFFFFFFFFul
+
+int microwatt_get_random_darn(unsigned long *v)
+{
+	unsigned long val;
+
+	/* Using DARN with L=1 - 64-bit conditioned random number */
+	asm volatile(PPC_DARN(%0, 1) : "=r"(val));
+
+	if (val == DARN_ERR)
+		return 0;
+
+	*v = val;
+
+	return 1;
+}
+
+static __init int rng_init(void)
+{
+	unsigned long val;
+	int i;
+
+	for (i = 0; i < 10; i++) {
+		if (microwatt_get_random_darn(&val)) {
+			ppc_md.get_random_seed = microwatt_get_random_darn;
+			return 0;
+		}
+	}
+
+	pr_warn("Unable to use DARN for get_random_seed()\n");
+
+	return -EIO;
+}
+machine_subsys_initcall(, rng_init);
-- 
2.31.1

Re: [PATCH v2 6/9] powerpc/microwatt: Add support for hardware random number generator

[Nicholas Piggin]

Excerpts from Paul Mackerras's message of June 18, 2021 1:47 pm:
> Microwatt's hardware RNG is accessed using the DARN instruction.
> 

I think we're getting a platforms/book3s soon with the VAS patches, 
might be a place to add the get_random_darn function.

Huh, DARN is unprivileged right? And yet we haven't wired it up in
pseries it still uses an hcall.

Anyway that's all stuff to sort out later.

Reviewed-by: Nicholas Piggin <npiggin@gmail.com>

> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
> ---
>  arch/powerpc/platforms/microwatt/Kconfig  |  1 +
>  arch/powerpc/platforms/microwatt/Makefile |  2 +-
>  arch/powerpc/platforms/microwatt/rng.c    | 48 +++++++++++++++++++++++
>  3 files changed, 50 insertions(+), 1 deletion(-)
>  create mode 100644 arch/powerpc/platforms/microwatt/rng.c
> 
> diff --git a/arch/powerpc/platforms/microwatt/Kconfig b/arch/powerpc/platforms/microwatt/Kconfig
> index 50ed0cedb5f1..8f6a81978461 100644
> --- a/arch/powerpc/platforms/microwatt/Kconfig
> +++ b/arch/powerpc/platforms/microwatt/Kconfig
> @@ -7,6 +7,7 @@ config PPC_MICROWATT
>  	select PPC_ICP_NATIVE
>  	select PPC_NATIVE
>  	select PPC_UDBG_16550
> +	select ARCH_RANDOM
>  	help
>            This option enables support for FPGA-based Microwatt implementations.
>  
> diff --git a/arch/powerpc/platforms/microwatt/Makefile b/arch/powerpc/platforms/microwatt/Makefile
> index e6885b3b2ee7..116d6d3ad3f0 100644
> --- a/arch/powerpc/platforms/microwatt/Makefile
> +++ b/arch/powerpc/platforms/microwatt/Makefile
> @@ -1 +1 @@
> -obj-y	+= setup.o
> +obj-y	+= setup.o rng.o
> diff --git a/arch/powerpc/platforms/microwatt/rng.c b/arch/powerpc/platforms/microwatt/rng.c
> new file mode 100644
> index 000000000000..3d8ee6eb7dad
> --- /dev/null
> +++ b/arch/powerpc/platforms/microwatt/rng.c
> @@ -0,0 +1,48 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Derived from arch/powerpc/platforms/powernv/rng.c, which is:
> + * Copyright 2013, Michael Ellerman, IBM Corporation.
> + */
> +
> +#define pr_fmt(fmt)	"microwatt-rng: " fmt
> +
> +#include <linux/kernel.h>
> +#include <linux/smp.h>
> +#include <asm/archrandom.h>
> +#include <asm/cputable.h>
> +#include <asm/machdep.h>
> +
> +#define DARN_ERR 0xFFFFFFFFFFFFFFFFul
> +
> +int microwatt_get_random_darn(unsigned long *v)
> +{
> +	unsigned long val;
> +
> +	/* Using DARN with L=1 - 64-bit conditioned random number */
> +	asm volatile(PPC_DARN(%0, 1) : "=r"(val));
> +
> +	if (val == DARN_ERR)
> +		return 0;
> +
> +	*v = val;
> +
> +	return 1;
> +}
> +
> +static __init int rng_init(void)
> +{
> +	unsigned long val;
> +	int i;
> +
> +	for (i = 0; i < 10; i++) {
> +		if (microwatt_get_random_darn(&val)) {
> +			ppc_md.get_random_seed = microwatt_get_random_darn;
> +			return 0;
> +		}
> +	}
> +
> +	pr_warn("Unable to use DARN for get_random_seed()\n");
> +
> +	return -EIO;
> +}
> +machine_subsys_initcall(, rng_init);
> -- 
> 2.31.1
> 
> 

Re: [PATCH v2 6/9] powerpc/microwatt: Add support for hardware random number generator

[Segher Boessenkool]

On Sat, Jun 19, 2021 at 01:08:51PM +1000, Nicholas Piggin wrote:
> Excerpts from Paul Mackerras's message of June 18, 2021 1:47 pm:
> > Microwatt's hardware RNG is accessed using the DARN instruction.
> 
> I think we're getting a platforms/book3s soon with the VAS patches, 
> might be a place to add the get_random_darn function.
> 
> Huh, DARN is unprivileged right?

It is, that's the whole point: to make it very very cheap for user
software it has to be an unprivileged instruction.


Segher

Re: [PATCH v2 6/9] powerpc/microwatt: Add support for hardware random number generator

[Nicholas Piggin]

Excerpts from Segher Boessenkool's message of June 20, 2021 12:36 am:
> On Sat, Jun 19, 2021 at 01:08:51PM +1000, Nicholas Piggin wrote:
>> Excerpts from Paul Mackerras's message of June 18, 2021 1:47 pm:
>> > Microwatt's hardware RNG is accessed using the DARN instruction.
>> 
>> I think we're getting a platforms/book3s soon with the VAS patches, 
>> might be a place to add the get_random_darn function.
>> 
>> Huh, DARN is unprivileged right?
> 
> It is, that's the whole point: to make it very very cheap for user
> software it has to be an unprivileged instruction.

Right, I was just doing a double-take. In that case we should enable it 
in the pseries random number code as well, so it really would be a 
generic isa 3.0 function that all (microwatt, powernv, pseries) could
use AFAIKS.

Thanks,
Nick

[PATCH v2 7/9] powerpc/microwatt: Add microwatt_defconfig

[Paul Mackerras]

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
---
 arch/powerpc/configs/microwatt_defconfig | 98 ++++++++++++++++++++++++
 1 file changed, 98 insertions(+)
 create mode 100644 arch/powerpc/configs/microwatt_defconfig

diff --git a/arch/powerpc/configs/microwatt_defconfig b/arch/powerpc/configs/microwatt_defconfig
new file mode 100644
index 000000000000..a08b739123da
--- /dev/null
+++ b/arch/powerpc/configs/microwatt_defconfig
@@ -0,0 +1,98 @@
+# CONFIG_SWAP is not set
+# CONFIG_CROSS_MEMORY_ATTACH is not set
+CONFIG_HIGH_RES_TIMERS=y
+CONFIG_PREEMPT_VOLUNTARY=y
+CONFIG_TICK_CPU_ACCOUNTING=y
+CONFIG_LOG_BUF_SHIFT=16
+CONFIG_PRINTK_SAFE_LOG_BUF_SHIFT=12
+CONFIG_BLK_DEV_INITRD=y
+CONFIG_CC_OPTIMIZE_FOR_SIZE=y
+CONFIG_KALLSYMS_ALL=y
+CONFIG_EMBEDDED=y
+# CONFIG_VM_EVENT_COUNTERS is not set
+# CONFIG_SLUB_DEBUG is not set
+# CONFIG_COMPAT_BRK is not set
+# CONFIG_SLAB_MERGE_DEFAULT is not set
+CONFIG_PPC64=y
+# CONFIG_PPC_KUEP is not set
+# CONFIG_PPC_KUAP is not set
+CONFIG_CPU_LITTLE_ENDIAN=y
+CONFIG_NR_IRQS=64
+CONFIG_PANIC_TIMEOUT=10
+# CONFIG_PPC_POWERNV is not set
+# CONFIG_PPC_PSERIES is not set
+CONFIG_PPC_MICROWATT=y
+# CONFIG_PPC_OF_BOOT_TRAMPOLINE is not set
+CONFIG_CPU_FREQ=y
+CONFIG_HZ_100=y
+# CONFIG_PPC_MEM_KEYS is not set
+# CONFIG_SECCOMP is not set
+# CONFIG_MQ_IOSCHED_KYBER is not set
+# CONFIG_COREDUMP is not set
+# CONFIG_COMPACTION is not set
+# CONFIG_MIGRATION is not set
+CONFIG_NET=y
+CONFIG_PACKET=y
+CONFIG_PACKET_DIAG=y
+CONFIG_UNIX=y
+CONFIG_UNIX_DIAG=y
+CONFIG_INET=y
+CONFIG_INET_UDP_DIAG=y
+CONFIG_INET_RAW_DIAG=y
+# CONFIG_WIRELESS is not set
+CONFIG_DEVTMPFS=y
+CONFIG_DEVTMPFS_MOUNT=y
+# CONFIG_STANDALONE is not set
+# CONFIG_PREVENT_FIRMWARE_BUILD is not set
+# CONFIG_FW_LOADER is not set
+# CONFIG_ALLOW_DEV_COREDUMP is not set
+CONFIG_MTD=y
+CONFIG_MTD_BLOCK=y
+CONFIG_MTD_PARTITIONED_MASTER=y
+CONFIG_MTD_SPI_NOR=y
+CONFIG_BLK_DEV_LOOP=y
+CONFIG_BLK_DEV_RAM=y
+CONFIG_NETDEVICES=y
+# CONFIG_WLAN is not set
+# CONFIG_INPUT is not set
+# CONFIG_SERIO is not set
+# CONFIG_VT is not set
+CONFIG_SERIAL_8250=y
+# CONFIG_SERIAL_8250_DEPRECATED_OPTIONS is not set
+CONFIG_SERIAL_8250_CONSOLE=y
+CONFIG_SERIAL_OF_PLATFORM=y
+CONFIG_SERIAL_NONSTANDARD=y
+# CONFIG_NVRAM is not set
+CONFIG_RANDOM_TRUST_CPU=y
+CONFIG_SPI=y
+CONFIG_SPI_DEBUG=y
+CONFIG_SPI_BITBANG=y
+CONFIG_SPI_SPIDEV=y
+# CONFIG_HWMON is not set
+# CONFIG_USB_SUPPORT is not set
+# CONFIG_VIRTIO_MENU is not set
+# CONFIG_IOMMU_SUPPORT is not set
+# CONFIG_NVMEM is not set
+CONFIG_EXT4_FS=y
+# CONFIG_FILE_LOCKING is not set
+# CONFIG_DNOTIFY is not set
+# CONFIG_INOTIFY_USER is not set
+# CONFIG_MISC_FILESYSTEMS is not set
+# CONFIG_CRYPTO_HW is not set
+# CONFIG_XZ_DEC_X86 is not set
+# CONFIG_XZ_DEC_IA64 is not set
+# CONFIG_XZ_DEC_ARM is not set
+# CONFIG_XZ_DEC_ARMTHUMB is not set
+# CONFIG_XZ_DEC_SPARC is not set
+CONFIG_PRINTK_TIME=y
+# CONFIG_SYMBOLIC_ERRNAME is not set
+# CONFIG_DEBUG_BUGVERBOSE is not set
+# CONFIG_DEBUG_MISC is not set
+# CONFIG_SCHED_DEBUG is not set
+# CONFIG_FTRACE is not set
+# CONFIG_STRICT_DEVMEM is not set
+CONFIG_PPC_DISABLE_WERROR=y
+CONFIG_XMON=y
+CONFIG_XMON_DEFAULT=y
+# CONFIG_XMON_DEFAULT_RO_MODE is not set
+# CONFIG_RUNTIME_TESTING_MENU is not set
-- 
2.31.1

[PATCH v2 8/9] powerpc/boot: Fixup device-tree on little endian

[Paul Mackerras]

From: Benjamin Herrenschmidt <benh@kernel.crashing.org>

This fixes the core devtree.c functions and the ns16550 UART backend.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
---
 arch/powerpc/boot/devtree.c | 59 +++++++++++++++++++++----------------
 arch/powerpc/boot/ns16550.c |  9 ++++--
 2 files changed, 41 insertions(+), 27 deletions(-)

diff --git a/arch/powerpc/boot/devtree.c b/arch/powerpc/boot/devtree.c
index 5d91036ad626..58fbcfcc98c9 100644
--- a/arch/powerpc/boot/devtree.c
+++ b/arch/powerpc/boot/devtree.c
@@ -13,6 +13,7 @@
 #include "string.h"
 #include "stdio.h"
 #include "ops.h"
+#include "of.h"
 
 void dt_fixup_memory(u64 start, u64 size)
 {
@@ -23,21 +24,25 @@ void dt_fixup_memory(u64 start, u64 size)
 	root = finddevice("/");
 	if (getprop(root, "#address-cells", &naddr, sizeof(naddr)) < 0)
 		naddr = 2;
+	else
+		naddr = be32_to_cpu(naddr);
 	if (naddr < 1 || naddr > 2)
 		fatal("Can't cope with #address-cells == %d in /\n\r", naddr);
 
 	if (getprop(root, "#size-cells", &nsize, sizeof(nsize)) < 0)
 		nsize = 1;
+	else
+		nsize = be32_to_cpu(nsize);
 	if (nsize < 1 || nsize > 2)
 		fatal("Can't cope with #size-cells == %d in /\n\r", nsize);
 
 	i = 0;
 	if (naddr == 2)
-		memreg[i++] = start >> 32;
-	memreg[i++] = start & 0xffffffff;
+		memreg[i++] = cpu_to_be32(start >> 32);
+	memreg[i++] = cpu_to_be32(start & 0xffffffff);
 	if (nsize == 2)
-		memreg[i++] = size >> 32;
-	memreg[i++] = size & 0xffffffff;
+		memreg[i++] = cpu_to_be32(size >> 32);
+	memreg[i++] = cpu_to_be32(size & 0xffffffff);
 
 	memory = finddevice("/memory");
 	if (! memory) {
@@ -45,9 +50,9 @@ void dt_fixup_memory(u64 start, u64 size)
 		setprop_str(memory, "device_type", "memory");
 	}
 
-	printf("Memory <- <0x%x", memreg[0]);
+	printf("Memory <- <0x%x", be32_to_cpu(memreg[0]));
 	for (i = 1; i < (naddr + nsize); i++)
-		printf(" 0x%x", memreg[i]);
+		printf(" 0x%x", be32_to_cpu(memreg[i]));
 	printf("> (%ldMB)\n\r", (unsigned long)(size >> 20));
 
 	setprop(memory, "reg", memreg, (naddr + nsize)*sizeof(u32));
@@ -65,10 +70,10 @@ void dt_fixup_cpu_clocks(u32 cpu, u32 tb, u32 bus)
 		printf("CPU bus-frequency <- 0x%x (%dMHz)\n\r", bus, MHZ(bus));
 
 	while ((devp = find_node_by_devtype(devp, "cpu"))) {
-		setprop_val(devp, "clock-frequency", cpu);
-		setprop_val(devp, "timebase-frequency", tb);
+		setprop_val(devp, "clock-frequency", cpu_to_be32(cpu));
+		setprop_val(devp, "timebase-frequency", cpu_to_be32(tb));
 		if (bus > 0)
-			setprop_val(devp, "bus-frequency", bus);
+			setprop_val(devp, "bus-frequency", cpu_to_be32(bus));
 	}
 
 	timebase_period_ns = 1000000000 / tb;
@@ -80,7 +85,7 @@ void dt_fixup_clock(const char *path, u32 freq)
 
 	if (devp) {
 		printf("%s: clock-frequency <- %x (%dMHz)\n\r", path, freq, MHZ(freq));
-		setprop_val(devp, "clock-frequency", freq);
+		setprop_val(devp, "clock-frequency", cpu_to_be32(freq));
 	}
 }
 
@@ -133,8 +138,12 @@ void dt_get_reg_format(void *node, u32 *naddr, u32 *nsize)
 {
 	if (getprop(node, "#address-cells", naddr, 4) != 4)
 		*naddr = 2;
+	else
+		*naddr = be32_to_cpu(*naddr);
 	if (getprop(node, "#size-cells", nsize, 4) != 4)
 		*nsize = 1;
+	else
+		*nsize = be32_to_cpu(*nsize);
 }
 
 static void copy_val(u32 *dest, u32 *src, int naddr)
@@ -163,9 +172,9 @@ static int add_reg(u32 *reg, u32 *add, int naddr)
 	int i, carry = 0;
 
 	for (i = MAX_ADDR_CELLS - 1; i >= MAX_ADDR_CELLS - naddr; i--) {
-		u64 tmp = (u64)reg[i] + add[i] + carry;
+		u64 tmp = (u64)be32_to_cpu(reg[i]) + be32_to_cpu(add[i]) + carry;
 		carry = tmp >> 32;
-		reg[i] = (u32)tmp;
+		reg[i] = cpu_to_be32((u32)tmp);
 	}
 
 	return !carry;
@@ -180,18 +189,18 @@ static int compare_reg(u32 *reg, u32 *range, u32 *rangesize)
 	u32 end;
 
 	for (i = 0; i < MAX_ADDR_CELLS; i++) {
-		if (reg[i] < range[i])
+		if (be32_to_cpu(reg[i]) < be32_to_cpu(range[i]))
 			return 0;
-		if (reg[i] > range[i])
+		if (be32_to_cpu(reg[i]) > be32_to_cpu(range[i]))
 			break;
 	}
 
 	for (i = 0; i < MAX_ADDR_CELLS; i++) {
-		end = range[i] + rangesize[i];
+		end = be32_to_cpu(range[i]) + be32_to_cpu(rangesize[i]);
 
-		if (reg[i] < end)
+		if (be32_to_cpu(reg[i]) < end)
 			break;
-		if (reg[i] > end)
+		if (be32_to_cpu(reg[i]) > end)
 			return 0;
 	}
 
@@ -240,7 +249,6 @@ static int dt_xlate(void *node, int res, int reglen, unsigned long *addr,
 		return 0;
 
 	dt_get_reg_format(parent, &naddr, &nsize);
-
 	if (nsize > 2)
 		return 0;
 
@@ -252,10 +260,10 @@ static int dt_xlate(void *node, int res, int reglen, unsigned long *addr,
 
 	copy_val(last_addr, prop_buf + offset, naddr);
 
-	ret_size = prop_buf[offset + naddr];
+	ret_size = be32_to_cpu(prop_buf[offset + naddr]);
 	if (nsize == 2) {
 		ret_size <<= 32;
-		ret_size |= prop_buf[offset + naddr + 1];
+		ret_size |= be32_to_cpu(prop_buf[offset + naddr + 1]);
 	}
 
 	for (;;) {
@@ -278,7 +286,6 @@ static int dt_xlate(void *node, int res, int reglen, unsigned long *addr,
 
 		offset = find_range(last_addr, prop_buf, prev_naddr,
 		                    naddr, prev_nsize, buflen / 4);
-
 		if (offset < 0)
 			return 0;
 
@@ -296,8 +303,7 @@ static int dt_xlate(void *node, int res, int reglen, unsigned long *addr,
 	if (naddr > 2)
 		return 0;
 
-	ret_addr = ((u64)last_addr[2] << 32) | last_addr[3];
-
+	ret_addr = ((u64)be32_to_cpu(last_addr[2]) << 32) | be32_to_cpu(last_addr[3]);
 	if (sizeof(void *) == 4 &&
 	    (ret_addr >= 0x100000000ULL || ret_size > 0x100000000ULL ||
 	     ret_addr + ret_size > 0x100000000ULL))
@@ -350,11 +356,14 @@ int dt_is_compatible(void *node, const char *compat)
 int dt_get_virtual_reg(void *node, void **addr, int nres)
 {
 	unsigned long xaddr;
-	int n;
+	int n, i;
 
 	n = getprop(node, "virtual-reg", addr, nres * 4);
-	if (n > 0)
+	if (n > 0) {
+		for (i = 0; i < n/4; i ++)
+			((u32 *)addr)[i] = be32_to_cpu(((u32 *)addr)[i]);
 		return n / 4;
+	}
 
 	for (n = 0; n < nres; n++) {
 		if (!dt_xlate_reg(node, n, &xaddr, NULL))
diff --git a/arch/powerpc/boot/ns16550.c b/arch/powerpc/boot/ns16550.c
index b0da4466d419..f16d2be1d0f3 100644
--- a/arch/powerpc/boot/ns16550.c
+++ b/arch/powerpc/boot/ns16550.c
@@ -15,6 +15,7 @@
 #include "stdio.h"
 #include "io.h"
 #include "ops.h"
+#include "of.h"
 
 #define UART_DLL	0	/* Out: Divisor Latch Low */
 #define UART_DLM	1	/* Out: Divisor Latch High */
@@ -58,16 +59,20 @@ int ns16550_console_init(void *devp, struct serial_console_data *scdp)
 	int n;
 	u32 reg_offset;
 
-	if (dt_get_virtual_reg(devp, (void **)&reg_base, 1) < 1)
+	if (dt_get_virtual_reg(devp, (void **)&reg_base, 1) < 1) {
+		printf("virt reg parse fail...\r\n");
 		return -1;
+	}
 
 	n = getprop(devp, "reg-offset", &reg_offset, sizeof(reg_offset));
 	if (n == sizeof(reg_offset))
-		reg_base += reg_offset;
+		reg_base += be32_to_cpu(reg_offset);
 
 	n = getprop(devp, "reg-shift", &reg_shift, sizeof(reg_shift));
 	if (n != sizeof(reg_shift))
 		reg_shift = 0;
+	else
+		reg_shift = be32_to_cpu(reg_shift);
 
 	scdp->open = ns16550_open;
 	scdp->putc = ns16550_putc;
-- 
2.31.1

Re: [PATCH v2 8/9] powerpc/boot: Fixup device-tree on little endian

[Nicholas Piggin]

Excerpts from Paul Mackerras's message of June 18, 2021 1:49 pm:
> From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> 
> This fixes the core devtree.c functions and the ns16550 UART backend.

Looks okay. Can sparse be run on arch/powerpc/boot? Would be nice to
get that working and endian annotations at some point.

> @@ -240,7 +249,6 @@ static int dt_xlate(void *node, int res, int reglen, unsigned long *addr,
>  		return 0;
>  
>  	dt_get_reg_format(parent, &naddr, &nsize);
> -
>  	if (nsize > 2)
>  		return 0;
>  

Unrelated hunk.

> @@ -278,7 +286,6 @@ static int dt_xlate(void *node, int res, int reglen, unsigned long *addr,
>  
>  		offset = find_range(last_addr, prop_buf, prev_naddr,
>  		                    naddr, prev_nsize, buflen / 4);
> -
>  		if (offset < 0)
>  			return 0;
>  

And there.

> diff --git a/arch/powerpc/boot/ns16550.c b/arch/powerpc/boot/ns16550.c
> index b0da4466d419..f16d2be1d0f3 100644
> --- a/arch/powerpc/boot/ns16550.c
> +++ b/arch/powerpc/boot/ns16550.c
> @@ -15,6 +15,7 @@
>  #include "stdio.h"
>  #include "io.h"
>  #include "ops.h"
> +#include "of.h"
>  
>  #define UART_DLL	0	/* Out: Divisor Latch Low */
>  #define UART_DLM	1	/* Out: Divisor Latch High */
> @@ -58,16 +59,20 @@ int ns16550_console_init(void *devp, struct serial_console_data *scdp)
>  	int n;
>  	u32 reg_offset;
>  
> -	if (dt_get_virtual_reg(devp, (void **)&reg_base, 1) < 1)
> +	if (dt_get_virtual_reg(devp, (void **)&reg_base, 1) < 1) {
> +		printf("virt reg parse fail...\r\n");
>  		return -1;
> +	}

Leftover debug.  Otherwise,

Acked-by: Nicholas Piggin <npiggin@gmail.com>

Thanks,
Nick

[PATCH v2 9/9] powerpc/boot: Add a boot wrapper for Microwatt

[Paul Mackerras]

From: Joel Stanley <joel@jms.id.au>

This allows microwatt's kernel to be built with an embedded device tree.

Load to arch/powerpc/boot/dtbImage.microwatt to 0x500000:

 mw_debug -b fpga stop load arch/powerpc/boot/dtbImage.microwatt 500000 start

Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
---
 arch/powerpc/boot/Makefile    |  4 ++++
 arch/powerpc/boot/microwatt.c | 24 ++++++++++++++++++++++++
 arch/powerpc/boot/wrapper     |  5 +++++
 3 files changed, 33 insertions(+)
 create mode 100644 arch/powerpc/boot/microwatt.c

diff --git a/arch/powerpc/boot/Makefile b/arch/powerpc/boot/Makefile
index 2b8da923ceca..dfaa4094fcae 100644
--- a/arch/powerpc/boot/Makefile
+++ b/arch/powerpc/boot/Makefile
@@ -163,6 +163,8 @@ src-plat-$(CONFIG_PPC_POWERNV) += pseries-head.S
 src-plat-$(CONFIG_PPC_IBM_CELL_BLADE) += pseries-head.S
 src-plat-$(CONFIG_MVME7100) += motload-head.S mvme7100.c
 
+src-plat-$(CONFIG_PPC_MICROWATT) += fixed-head.S microwatt.c
+
 src-wlib := $(sort $(src-wlib-y))
 src-plat := $(sort $(src-plat-y))
 src-boot := $(src-wlib) $(src-plat) empty.c
@@ -355,6 +357,8 @@ image-$(CONFIG_MVME5100)		+= dtbImage.mvme5100
 # Board port in arch/powerpc/platform/amigaone/Kconfig
 image-$(CONFIG_AMIGAONE)		+= cuImage.amigaone
 
+image-$(CONFIG_PPC_MICROWATT)		+= dtbImage.microwatt
+
 # For 32-bit powermacs, build the COFF and miboot images
 # as well as the ELF images.
 ifdef CONFIG_PPC32
diff --git a/arch/powerpc/boot/microwatt.c b/arch/powerpc/boot/microwatt.c
new file mode 100644
index 000000000000..ca9d83617fc1
--- /dev/null
+++ b/arch/powerpc/boot/microwatt.c
@@ -0,0 +1,24 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <stddef.h>
+#include "stdio.h"
+#include "types.h"
+#include "io.h"
+#include "ops.h"
+
+BSS_STACK(8192);
+
+void platform_init(unsigned long r3, unsigned long r4, unsigned long r5)
+{
+	unsigned long heapsize = 16*1024*1024 - (unsigned long)_end;
+
+	/*
+	 * Disable interrupts and turn off MSR_RI, since we'll
+	 * shortly be overwriting the interrupt vectors.
+	 */
+	__asm__ volatile("mtmsrd %0,1" : : "r" (0));
+
+	simple_alloc_init(_end, heapsize, 32, 64);
+	fdt_init(_dtb_start);
+	serial_console_init();
+}
diff --git a/arch/powerpc/boot/wrapper b/arch/powerpc/boot/wrapper
index 41fa0a8715e3..ae48fffa1e13 100755
--- a/arch/powerpc/boot/wrapper
+++ b/arch/powerpc/boot/wrapper
@@ -342,6 +342,11 @@ gamecube|wii)
     link_address='0x600000'
     platformo="$object/$platform-head.o $object/$platform.o"
     ;;
+microwatt)
+    link_address='0x500000'
+    platformo="$object/fixed-head.o $object/$platform.o"
+    binary=y
+    ;;
 treeboot-currituck)
     link_address='0x1000000'
     ;;
-- 
2.31.1

Re: [PATCH v2 9/9] powerpc/boot: Add a boot wrapper for Microwatt

[Nicholas Piggin]

Excerpts from Paul Mackerras's message of June 18, 2021 1:49 pm:
> From: Joel Stanley <joel@jms.id.au>
> 
> This allows microwatt's kernel to be built with an embedded device tree.
> 
> Load to arch/powerpc/boot/dtbImage.microwatt to 0x500000:
> 
>  mw_debug -b fpga stop load arch/powerpc/boot/dtbImage.microwatt 500000 start
> 
> Signed-off-by: Joel Stanley <joel@jms.id.au>
> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>

Thanks for folding and commenting that change. Ack for this and the rest 
of the platform and dt and interrupt handling patches FWIW, but I don't 
know much about any of these areas to give an informed review.

Thanks,
Nick

> ---
>  arch/powerpc/boot/Makefile    |  4 ++++
>  arch/powerpc/boot/microwatt.c | 24 ++++++++++++++++++++++++
>  arch/powerpc/boot/wrapper     |  5 +++++
>  3 files changed, 33 insertions(+)
>  create mode 100644 arch/powerpc/boot/microwatt.c
> 
> diff --git a/arch/powerpc/boot/Makefile b/arch/powerpc/boot/Makefile
> index 2b8da923ceca..dfaa4094fcae 100644
> --- a/arch/powerpc/boot/Makefile
> +++ b/arch/powerpc/boot/Makefile
> @@ -163,6 +163,8 @@ src-plat-$(CONFIG_PPC_POWERNV) += pseries-head.S
>  src-plat-$(CONFIG_PPC_IBM_CELL_BLADE) += pseries-head.S
>  src-plat-$(CONFIG_MVME7100) += motload-head.S mvme7100.c
>  
> +src-plat-$(CONFIG_PPC_MICROWATT) += fixed-head.S microwatt.c
> +
>  src-wlib := $(sort $(src-wlib-y))
>  src-plat := $(sort $(src-plat-y))
>  src-boot := $(src-wlib) $(src-plat) empty.c
> @@ -355,6 +357,8 @@ image-$(CONFIG_MVME5100)		+= dtbImage.mvme5100
>  # Board port in arch/powerpc/platform/amigaone/Kconfig
>  image-$(CONFIG_AMIGAONE)		+= cuImage.amigaone
>  
> +image-$(CONFIG_PPC_MICROWATT)		+= dtbImage.microwatt
> +
>  # For 32-bit powermacs, build the COFF and miboot images
>  # as well as the ELF images.
>  ifdef CONFIG_PPC32
> diff --git a/arch/powerpc/boot/microwatt.c b/arch/powerpc/boot/microwatt.c
> new file mode 100644
> index 000000000000..ca9d83617fc1
> --- /dev/null
> +++ b/arch/powerpc/boot/microwatt.c
> @@ -0,0 +1,24 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +
> +#include <stddef.h>
> +#include "stdio.h"
> +#include "types.h"
> +#include "io.h"
> +#include "ops.h"
> +
> +BSS_STACK(8192);
> +
> +void platform_init(unsigned long r3, unsigned long r4, unsigned long r5)
> +{
> +	unsigned long heapsize = 16*1024*1024 - (unsigned long)_end;
> +
> +	/*
> +	 * Disable interrupts and turn off MSR_RI, since we'll
> +	 * shortly be overwriting the interrupt vectors.
> +	 */
> +	__asm__ volatile("mtmsrd %0,1" : : "r" (0));
> +
> +	simple_alloc_init(_end, heapsize, 32, 64);
> +	fdt_init(_dtb_start);
> +	serial_console_init();
> +}
> diff --git a/arch/powerpc/boot/wrapper b/arch/powerpc/boot/wrapper
> index 41fa0a8715e3..ae48fffa1e13 100755
> --- a/arch/powerpc/boot/wrapper
> +++ b/arch/powerpc/boot/wrapper
> @@ -342,6 +342,11 @@ gamecube|wii)
>      link_address='0x600000'
>      platformo="$object/$platform-head.o $object/$platform.o"
>      ;;
> +microwatt)
> +    link_address='0x500000'
> +    platformo="$object/fixed-head.o $object/$platform.o"
> +    binary=y
> +    ;;
>  treeboot-currituck)
>      link_address='0x1000000'
>      ;;
> -- 
> 2.31.1
> 
> 

Re: [PATCH v2 0/9] powerpc: Add support for Microwatt soft-core

[Segher Boessenkool]

On Fri, Jun 18, 2021 at 01:42:53PM +1000, Paul Mackerras wrote:
> This series of patches adds support for the Microwatt soft-core.
> Microwatt is an open-source 64-bit Power ISA processor written in VHDL
> which targets medium-sized FPGAs such as the Xilinx Artix-7 or the
> Lattice ECP5.  Microwatt currently implements the scalar fixed plus
> floating-point subset of Power ISA v3.0B plus the radix MMU, but not
> logical partitioning (i.e. it does not have hypervisor mode or nested
> radix translation).

For the whole series:

Reviewed-by: Segher Boessenkool <segher@kernel.crashing.org>

I didn't see anything in this revision that would prevent it from
being included upstream (that HV=1 thing should be fixed sooner rather
than later, but that is not a kernel problem).  Looks in great state :-)


Segher

Re: [PATCH v2 0/9] powerpc: Add support for Microwatt soft-core

[Michael Ellerman]

On Fri, 18 Jun 2021 13:42:53 +1000, Paul Mackerras wrote:
> This series of patches adds support for the Microwatt soft-core.
> Microwatt is an open-source 64-bit Power ISA processor written in VHDL
> which targets medium-sized FPGAs such as the Xilinx Artix-7 or the
> Lattice ECP5.  Microwatt currently implements the scalar fixed plus
> floating-point subset of Power ISA v3.0B plus the radix MMU, but not
> logical partitioning (i.e. it does not have hypervisor mode or nested
> radix translation).
> 
> [...]

Applied to powerpc/next.

[1/9] powerpc: Add Microwatt platform
      https://git.kernel.org/powerpc/c/53d143fe08c24c2ce44ee329e41c2a6aad57ebb5
[2/9] powerpc: Add Microwatt device tree
      https://git.kernel.org/powerpc/c/151b88e8482167f6eb3117d82e4905efb5e72662
[3/9] powerpc/microwatt: Populate platform bus from device-tree
      https://git.kernel.org/powerpc/c/0d0f9e5f2fa7aacf22892078a1065fa5d0ce941b
[4/9] powerpc/xics: Add a native ICS backend for microwatt
      https://git.kernel.org/powerpc/c/aa9c5adf2f61da39c92280d9336e091852e292ff
[5/9] powerpc/microwatt: Use standard 16550 UART for console
      https://git.kernel.org/powerpc/c/48b545b8018db61ab4978d29c73c16b9fbfad12c
[6/9] powerpc/microwatt: Add support for hardware random number generator
      https://git.kernel.org/powerpc/c/c25769fddaec13509b6cdc7ad17458f239c4cee7
[7/9] powerpc/microwatt: Add microwatt_defconfig
      https://git.kernel.org/powerpc/c/4a1511eb342bd80c6ea0e8a7ce0bbe68aac96ac5
[8/9] powerpc/boot: Fixup device-tree on little endian
      https://git.kernel.org/powerpc/c/c93f80849bdd9b45d834053ae1336e28f0026c84
[9/9] powerpc/boot: Add a boot wrapper for Microwatt
      https://git.kernel.org/powerpc/c/4a21192e2796c3338c4b0083b494a84a61311aaf

cheers