[PATCH v8 0/4] m68k: Add Virtual M68k Machine

[PATCH v8 0/4] m68k: Add Virtual M68k Machine

[Laurent Vivier]

The most powerful m68k machine emulated by QEMU is a Quadra 800,
but this machine is very limited: only 1 GiB of memory and only some
specific interfaces, with no DMA.

The Virtual M68k Machine is based on Goldfish interfaces defined by Google
for Android simulator. It uses Goldfish-rtc (timer and RTC),
Goldfish-pic (PIC) and Goldfish-tty (for early tty).

The machine is created with 128 virtio-mmio buses, and they can
be used to add serial console, GPU, disk, NIC, HID, hwrng, 9PFS...

The virtual m68k machine has been merged in QEMU and will be available
with the release 6.0.

This series introduces the support of this new machine in the linux kernel.

If you want to try:

- Configure and build latest QEMU with (or download qemu 6.0 binary):

  .../configure --target-list=m68k-softmmu --enable-virglrenderer
  make

- Configure and build linux with:

  make virt_defconfig
  make vmlinux

A pre-installed qcow2 disk image is available at:

http://vivier.eu/debian-10.0.qcow2

You can run the machine with something like:

qemu-system-m68k -M virt \
  -m 3G \
  -chardev stdio,signal=off,mux=on,id=char0 \
  -mon chardev=char0,mode=readline \
  -kernel vmlinux \
  -append "console=hvc0 root=/dev/vda2" \
  -blockdev node-name=system,driver=file,filename=debian-10.0.qcow2 \
  -blockdev node-name=drive0,driver=qcow2,file=system \
  -device virtio-blk-device,drive=drive0 \
  -serial chardev:char0 \
  -device virtio-net-device,netdev=hostnet0 \
  -netdev bridge,id=hostnet0,br=virbr0,helper=/usr/libexec/qemu-bridge-helper \
  -device virtio-serial-device \
  -device virtio-gpu-device \
  -device virtconsole,chardev=char0 \
  -device virtio-keyboard-device \
  -device virtio-mouse-device

You can watch a presentation about the machine on the Planet m68k channel:

    https://youtu.be/s_ve0bCC9q4
    [Demo at 38:00]

v8:
- GF_PUT_CHAR is a 32bit register (in arch/m68k/kernel/head.S)
- rework goldfish-pic and virt_ctrl

v7:
- add "#include <linux/slab.h>" in timer-goldfish.c for kzalloc()
- update timer-goldfish Kconfig
- remove EXPORT_SYMBOL()
- introduce goldfish_ioread32()/goldfish_iowrite32()

v6:
- fix goldfish-rtc endianness
- move goldfish-timer code to drivers/clocksource
- remove LEGACY_TIMER_TICK and use directly goldfish-timer

v5:
- add GENERIC_CLOCKEVENTS in Kconfig.machine

v4:
- update PATCH 1: comments and parameter names
- add a patch to move to generic clockevents
  (I prefer to have a separate patch as it can be used as an example to
   move from legacy timer tick to generic clockevents)

v3:
- introduce config.h to export prototypes to arch/m68k/kernel/setup_mm.c
- define virt_nmi_handler as static

v2:
- Remove VIRTO_MENU set y
- sort the selects
- add CONFIG_LOCALVERSION="-virt"
- generate virt_defconfig using "make savedefconfig"
- rename MACH_VIRTONLY to MACH_VIRT_ONLY
- add a test_notvirt label in head.S
- rework iounmap() to use two separate #ifdefs
- use %u in virt_get_model()
- drop show_registers() in config.c
- drop pr_err() from config_virt()
- sort includes in ints.c
- call virt_irq_enable() in virt_irq_startup()
- drop virt_irq_shutdown() and use virt_irq_disable()
- move in_nmi into virt_nmi_handler()
- use pr_warn() in virt_nmi_handler()
- rework goldfish_pic_irq() IRQ scan
- copy goldfish-pic IRQs related information from QEMU hw/m68k/virt
- add a comment to "min_low_pfn = 0"
- use platform_device_register_simple()
- use goldfish_timer_read(), upper_32_bits() and lower_32_bits()

Thanks,
Laurent

Laurent Vivier (4):
  m68k: add asm/config.h
  rtc: goldfish: introduce goldfish_ioread32()/goldfish_iowrite32()
  clocksource/drivers: Add a goldfish-timer clocksource
  m68k: introduce a virtual m68k machine

 arch/m68k/Kbuild                           |   1 +
 arch/m68k/Kconfig.machine                  |  17 +++
 arch/m68k/amiga/config.c                   |   1 +
 arch/m68k/apollo/config.c                  |   1 +
 arch/m68k/atari/config.c                   |   1 +
 arch/m68k/bvme6000/config.c                |   1 +
 arch/m68k/configs/virt_defconfig           |  65 ++++++++++
 arch/m68k/hp300/config.c                   |   1 +
 arch/m68k/include/asm/config.h             |  35 ++++++
 arch/m68k/include/asm/irq.h                |   3 +-
 arch/m68k/include/asm/pgtable_mm.h         |   7 ++
 arch/m68k/include/asm/setup.h              |  44 +++++--
 arch/m68k/include/asm/virt.h               |  25 ++++
 arch/m68k/include/uapi/asm/bootinfo-virt.h |  18 +++
 arch/m68k/include/uapi/asm/bootinfo.h      |   1 +
 arch/m68k/kernel/Makefile                  |   1 +
 arch/m68k/kernel/head.S                    |  31 +++++
 arch/m68k/kernel/setup_mm.c                |  30 ++---
 arch/m68k/mac/config.c                     |   1 +
 arch/m68k/mm/kmap.c                        |  23 ++--
 arch/m68k/mvme147/config.c                 |   1 +
 arch/m68k/mvme16x/config.c                 |   1 +
 arch/m68k/q40/config.c                     |   1 +
 arch/m68k/virt/Makefile                    |   6 +
 arch/m68k/virt/config.c                    | 119 ++++++++++++++++++
 arch/m68k/virt/ints.c                      | 133 ++++++++++++++++++++
 arch/m68k/virt/platform.c                  |  72 +++++++++++
 drivers/clocksource/Kconfig                |   7 ++
 drivers/clocksource/Makefile               |   1 +
 drivers/clocksource/timer-goldfish.c       | 139 +++++++++++++++++++++
 drivers/rtc/rtc-goldfish.c                 |  39 +++---
 include/clocksource/timer-goldfish.h       |  11 ++
 32 files changed, 782 insertions(+), 55 deletions(-)
 create mode 100644 arch/m68k/configs/virt_defconfig
 create mode 100644 arch/m68k/include/asm/config.h
 create mode 100644 arch/m68k/include/asm/virt.h
 create mode 100644 arch/m68k/include/uapi/asm/bootinfo-virt.h
 create mode 100644 arch/m68k/virt/Makefile
 create mode 100644 arch/m68k/virt/config.c
 create mode 100644 arch/m68k/virt/ints.c
 create mode 100644 arch/m68k/virt/platform.c
 create mode 100644 drivers/clocksource/timer-goldfish.c
 create mode 100644 include/clocksource/timer-goldfish.h

-- 
2.34.1

[PATCH v8 1/4] m68k: add asm/config.h

[Laurent Vivier]

To avoid 'warning: no previous prototype for' error, declare all
the parse_bootinfo and config functions prototypes into asm/config.h
and include it in arch/m68k/kernel/setup_mm.c and arch/m68k/*/config.c

Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
---
 arch/m68k/amiga/config.c       |  1 +
 arch/m68k/apollo/config.c      |  1 +
 arch/m68k/atari/config.c       |  1 +
 arch/m68k/bvme6000/config.c    |  1 +
 arch/m68k/hp300/config.c       |  1 +
 arch/m68k/include/asm/config.h | 33 +++++++++++++++++++++++++++++++++
 arch/m68k/kernel/setup_mm.c    | 23 +----------------------
 arch/m68k/mac/config.c         |  1 +
 arch/m68k/mvme147/config.c     |  1 +
 arch/m68k/mvme16x/config.c     |  1 +
 arch/m68k/q40/config.c         |  1 +
 11 files changed, 43 insertions(+), 22 deletions(-)
 create mode 100644 arch/m68k/include/asm/config.h

diff --git a/arch/m68k/amiga/config.c b/arch/m68k/amiga/config.c
index be2dfab48fd4..3137b45750df 100644
--- a/arch/m68k/amiga/config.c
+++ b/arch/m68k/amiga/config.c
@@ -37,6 +37,7 @@
 #include <asm/irq.h>
 #include <asm/machdep.h>
 #include <asm/io.h>
+#include <asm/config.h>
 
 static unsigned long amiga_model;
 
diff --git a/arch/m68k/apollo/config.c b/arch/m68k/apollo/config.c
index 581a5f68d102..42a8b8e2b664 100644
--- a/arch/m68k/apollo/config.c
+++ b/arch/m68k/apollo/config.c
@@ -16,6 +16,7 @@
 #include <asm/apollohw.h>
 #include <asm/irq.h>
 #include <asm/machdep.h>
+#include <asm/config.h>
 
 u_long sio01_physaddr;
 u_long sio23_physaddr;
diff --git a/arch/m68k/atari/config.c b/arch/m68k/atari/config.c
index 261a0f57cc9a..38a7c0578105 100644
--- a/arch/m68k/atari/config.c
+++ b/arch/m68k/atari/config.c
@@ -46,6 +46,7 @@
 #include <asm/machdep.h>
 #include <asm/hwtest.h>
 #include <asm/io.h>
+#include <asm/config.h>
 
 u_long atari_mch_cookie;
 EXPORT_SYMBOL(atari_mch_cookie);
diff --git a/arch/m68k/bvme6000/config.c b/arch/m68k/bvme6000/config.c
index 0c6feafbbd11..9b060d466e03 100644
--- a/arch/m68k/bvme6000/config.c
+++ b/arch/m68k/bvme6000/config.c
@@ -36,6 +36,7 @@
 #include <asm/traps.h>
 #include <asm/machdep.h>
 #include <asm/bvme6000hw.h>
+#include <asm/config.h>
 
 static void bvme6000_get_model(char *model);
 extern void bvme6000_sched_init(void);
diff --git a/arch/m68k/hp300/config.c b/arch/m68k/hp300/config.c
index ce1eb3d3d55d..2c92843397c3 100644
--- a/arch/m68k/hp300/config.c
+++ b/arch/m68k/hp300/config.c
@@ -22,6 +22,7 @@
 #include <asm/blinken.h>
 #include <asm/io.h>                               /* readb() and writeb() */
 #include <asm/hp300hw.h>
+#include <asm/config.h>
 
 #include "time.h"
 
diff --git a/arch/m68k/include/asm/config.h b/arch/m68k/include/asm/config.h
new file mode 100644
index 000000000000..aae61070628b
--- /dev/null
+++ b/arch/m68k/include/asm/config.h
@@ -0,0 +1,33 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+/*
+ * This file contains prototypes provided by each m68k machine
+ * to parse bootinfo data structures and to configure the machine
+ */
+
+#ifndef _M68K_CONFIG_H
+#define _M68K_CONFIG_H
+
+extern int amiga_parse_bootinfo(const struct bi_record *record);
+extern int atari_parse_bootinfo(const struct bi_record *record);
+extern int mac_parse_bootinfo(const struct bi_record *record);
+extern int q40_parse_bootinfo(const struct bi_record *record);
+extern int bvme6000_parse_bootinfo(const struct bi_record *record);
+extern int mvme16x_parse_bootinfo(const struct bi_record *record);
+extern int mvme147_parse_bootinfo(const struct bi_record *record);
+extern int hp300_parse_bootinfo(const struct bi_record *record);
+extern int apollo_parse_bootinfo(const struct bi_record *record);
+
+extern void config_amiga(void);
+extern void config_atari(void);
+extern void config_mac(void);
+extern void config_sun3(void);
+extern void config_apollo(void);
+extern void config_mvme147(void);
+extern void config_mvme16x(void);
+extern void config_bvme6000(void);
+extern void config_hp300(void);
+extern void config_q40(void);
+extern void config_sun3x(void);
+
+#endif /* _M68K_CONFIG_H */
diff --git a/arch/m68k/kernel/setup_mm.c b/arch/m68k/kernel/setup_mm.c
index 4b51bfd38e5f..226dc3750397 100644
--- a/arch/m68k/kernel/setup_mm.c
+++ b/arch/m68k/kernel/setup_mm.c
@@ -47,6 +47,7 @@
 #endif
 #include <asm/macintosh.h>
 #include <asm/natfeat.h>
+#include <asm/config.h>
 
 #if !FPSTATESIZE || !NR_IRQS
 #warning No CPU/platform type selected, your kernel will not work!
@@ -113,28 +114,6 @@ EXPORT_SYMBOL(isa_type);
 EXPORT_SYMBOL(isa_sex);
 #endif
 
-extern int amiga_parse_bootinfo(const struct bi_record *);
-extern int atari_parse_bootinfo(const struct bi_record *);
-extern int mac_parse_bootinfo(const struct bi_record *);
-extern int q40_parse_bootinfo(const struct bi_record *);
-extern int bvme6000_parse_bootinfo(const struct bi_record *);
-extern int mvme16x_parse_bootinfo(const struct bi_record *);
-extern int mvme147_parse_bootinfo(const struct bi_record *);
-extern int hp300_parse_bootinfo(const struct bi_record *);
-extern int apollo_parse_bootinfo(const struct bi_record *);
-
-extern void config_amiga(void);
-extern void config_atari(void);
-extern void config_mac(void);
-extern void config_sun3(void);
-extern void config_apollo(void);
-extern void config_mvme147(void);
-extern void config_mvme16x(void);
-extern void config_bvme6000(void);
-extern void config_hp300(void);
-extern void config_q40(void);
-extern void config_sun3x(void);
-
 #define MASK_256K 0xfffc0000
 
 extern void paging_init(void);
diff --git a/arch/m68k/mac/config.c b/arch/m68k/mac/config.c
index 5d16f9b47aa9..65d124ec80bb 100644
--- a/arch/m68k/mac/config.c
+++ b/arch/m68k/mac/config.c
@@ -47,6 +47,7 @@
 #include <asm/mac_via.h>
 #include <asm/mac_oss.h>
 #include <asm/mac_psc.h>
+#include <asm/config.h>
 
 /* Mac bootinfo struct */
 struct mac_booter_data mac_bi_data;
diff --git a/arch/m68k/mvme147/config.c b/arch/m68k/mvme147/config.c
index dfd6202fd403..b96ea7c76a19 100644
--- a/arch/m68k/mvme147/config.c
+++ b/arch/m68k/mvme147/config.c
@@ -34,6 +34,7 @@
 #include <asm/traps.h>
 #include <asm/machdep.h>
 #include <asm/mvme147hw.h>
+#include <asm/config.h>
 
 
 static void mvme147_get_model(char *model);
diff --git a/arch/m68k/mvme16x/config.c b/arch/m68k/mvme16x/config.c
index b4422c2dfbbf..88cbdc10925b 100644
--- a/arch/m68k/mvme16x/config.c
+++ b/arch/m68k/mvme16x/config.c
@@ -37,6 +37,7 @@
 #include <asm/traps.h>
 #include <asm/machdep.h>
 #include <asm/mvme16xhw.h>
+#include <asm/config.h>
 
 extern t_bdid mvme_bdid;
 
diff --git a/arch/m68k/q40/config.c b/arch/m68k/q40/config.c
index 5caf1e5be1c2..9237243077ce 100644
--- a/arch/m68k/q40/config.c
+++ b/arch/m68k/q40/config.c
@@ -34,6 +34,7 @@
 #include <asm/traps.h>
 #include <asm/machdep.h>
 #include <asm/q40_master.h>
+#include <asm/config.h>
 
 extern void q40_init_IRQ(void);
 static void q40_get_model(char *model);
-- 
2.34.1

[PATCH v8 2/4] rtc: goldfish: introduce goldfish_ioread32()/goldfish_iowrite32()

[Laurent Vivier]

The goldfish device always uses the same endianness as the architecture
using it:
https://android.googlesource.com/platform/external/qemu/+/refs/heads/emu-master-dev/hw/timer/goldfish_timer.c#177

On a big-endian machine, the device is also big-endian, on a
little-endian machine the device is little-endian.

So we need to use the right accessor to read/write values to the goldfish
registers: ioread32()/iowrite32() on a little-endian machine,
ioread32be()/iowrite32be() on a big-endian machine.

This patch introduces goldfish_ioread32()/goldfish_iowrite32() that uses
the expected accessor according to the machine endianness.

Signed-off-by: Laurent Vivier <laurent@vivier.eu>
---
 drivers/rtc/rtc-goldfish.c | 39 +++++++++++++++++++++++---------------
 1 file changed, 24 insertions(+), 15 deletions(-)

diff --git a/drivers/rtc/rtc-goldfish.c b/drivers/rtc/rtc-goldfish.c
index 7ab95d052644..b0cae4729b03 100644
--- a/drivers/rtc/rtc-goldfish.c
+++ b/drivers/rtc/rtc-goldfish.c
@@ -23,6 +23,15 @@
 #define TIMER_ALARM_STATUS	0x18
 #define TIMER_CLEAR_INTERRUPT	0x1c
 
+/* goldfish endianness depends on CPU endianness */
+#ifdef CONFIG_CPU_BIG_ENDIAN
+#define goldfish_ioread32 ioread32be
+#define goldfish_iowrite32 iowrite32be
+#else
+#define goldfish_ioread32 ioread32
+#define goldfish_iowrite32 iowrite32
+#endif
+
 struct goldfish_rtc {
 	void __iomem *base;
 	int irq;
@@ -41,8 +50,8 @@ static int goldfish_rtc_read_alarm(struct device *dev,
 	rtcdrv = dev_get_drvdata(dev);
 	base = rtcdrv->base;
 
-	rtc_alarm_low = readl(base + TIMER_ALARM_LOW);
-	rtc_alarm_high = readl(base + TIMER_ALARM_HIGH);
+	rtc_alarm_low = goldfish_ioread32(base + TIMER_ALARM_LOW);
+	rtc_alarm_high = goldfish_ioread32(base + TIMER_ALARM_HIGH);
 	rtc_alarm = (rtc_alarm_high << 32) | rtc_alarm_low;
 
 	do_div(rtc_alarm, NSEC_PER_SEC);
@@ -50,7 +59,7 @@ static int goldfish_rtc_read_alarm(struct device *dev,
 
 	rtc_time64_to_tm(rtc_alarm, &alrm->time);
 
-	if (readl(base + TIMER_ALARM_STATUS))
+	if (goldfish_ioread32(base + TIMER_ALARM_STATUS))
 		alrm->enabled = 1;
 	else
 		alrm->enabled = 0;
@@ -71,18 +80,18 @@ static int goldfish_rtc_set_alarm(struct device *dev,
 
 	if (alrm->enabled) {
 		rtc_alarm64 = rtc_tm_to_time64(&alrm->time) * NSEC_PER_SEC;
-		writel((rtc_alarm64 >> 32), base + TIMER_ALARM_HIGH);
-		writel(rtc_alarm64, base + TIMER_ALARM_LOW);
-		writel(1, base + TIMER_IRQ_ENABLED);
+		goldfish_iowrite32((rtc_alarm64 >> 32), base + TIMER_ALARM_HIGH);
+		goldfish_iowrite32(rtc_alarm64, base + TIMER_ALARM_LOW);
+		goldfish_iowrite32(1, base + TIMER_IRQ_ENABLED);
 	} else {
 		/*
 		 * if this function was called with enabled=0
 		 * then it could mean that the application is
 		 * trying to cancel an ongoing alarm
 		 */
-		rtc_status_reg = readl(base + TIMER_ALARM_STATUS);
+		rtc_status_reg = goldfish_ioread32(base + TIMER_ALARM_STATUS);
 		if (rtc_status_reg)
-			writel(1, base + TIMER_CLEAR_ALARM);
+			goldfish_iowrite32(1, base + TIMER_CLEAR_ALARM);
 	}
 
 	return 0;
@@ -98,9 +107,9 @@ static int goldfish_rtc_alarm_irq_enable(struct device *dev,
 	base = rtcdrv->base;
 
 	if (enabled)
-		writel(1, base + TIMER_IRQ_ENABLED);
+		goldfish_iowrite32(1, base + TIMER_IRQ_ENABLED);
 	else
-		writel(0, base + TIMER_IRQ_ENABLED);
+		goldfish_iowrite32(0, base + TIMER_IRQ_ENABLED);
 
 	return 0;
 }
@@ -110,7 +119,7 @@ static irqreturn_t goldfish_rtc_interrupt(int irq, void *dev_id)
 	struct goldfish_rtc *rtcdrv = dev_id;
 	void __iomem *base = rtcdrv->base;
 
-	writel(1, base + TIMER_CLEAR_INTERRUPT);
+	goldfish_iowrite32(1, base + TIMER_CLEAR_INTERRUPT);
 
 	rtc_update_irq(rtcdrv->rtc, 1, RTC_IRQF | RTC_AF);
 
@@ -128,8 +137,8 @@ static int goldfish_rtc_read_time(struct device *dev, struct rtc_time *tm)
 	rtcdrv = dev_get_drvdata(dev);
 	base = rtcdrv->base;
 
-	time_low = readl(base + TIMER_TIME_LOW);
-	time_high = readl(base + TIMER_TIME_HIGH);
+	time_low = goldfish_ioread32(base + TIMER_TIME_LOW);
+	time_high = goldfish_ioread32(base + TIMER_TIME_HIGH);
 	time = (time_high << 32) | time_low;
 
 	do_div(time, NSEC_PER_SEC);
@@ -149,8 +158,8 @@ static int goldfish_rtc_set_time(struct device *dev, struct rtc_time *tm)
 	base = rtcdrv->base;
 
 	now64 = rtc_tm_to_time64(tm) * NSEC_PER_SEC;
-	writel((now64 >> 32), base + TIMER_TIME_HIGH);
-	writel(now64, base + TIMER_TIME_LOW);
+	goldfish_iowrite32((now64 >> 32), base + TIMER_TIME_HIGH);
+	goldfish_iowrite32(now64, base + TIMER_TIME_LOW);
 
 	return 0;
 }
-- 
2.34.1

[PATCH v8 3/4] clocksource/drivers: Add a goldfish-timer clocksource

[Laurent Vivier]

Add a clocksource based on the goldfish-rtc device.

Signed-off-by: Laurent Vivier <laurent@vivier.eu>
---
 drivers/clocksource/Kconfig          |   7 ++
 drivers/clocksource/Makefile         |   1 +
 drivers/clocksource/timer-goldfish.c | 139 +++++++++++++++++++++++++++
 include/clocksource/timer-goldfish.h |  11 +++
 4 files changed, 158 insertions(+)
 create mode 100644 drivers/clocksource/timer-goldfish.c
 create mode 100644 include/clocksource/timer-goldfish.h

diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index f65e31bab9ae..fa66fb7156da 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -711,4 +711,11 @@ config MICROCHIP_PIT64B
 	  modes and high resolution. It is used as a clocksource
 	  and a clockevent.
 
+config GOLDFISH_TIMER
+	bool "Clocksource using goldfish-rtc"
+	depends on M68K || COMPILE_TEST
+	depends on RTC_DRV_GOLDFISH
+	help
+	  Support for the timer/counter of goldfish-rtc
+
 endmenu
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index c17ee32a7151..e624a1a27027 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -88,3 +88,4 @@ obj-$(CONFIG_CSKY_MP_TIMER)		+= timer-mp-csky.o
 obj-$(CONFIG_GX6605S_TIMER)		+= timer-gx6605s.o
 obj-$(CONFIG_HYPERV_TIMER)		+= hyperv_timer.o
 obj-$(CONFIG_MICROCHIP_PIT64B)		+= timer-microchip-pit64b.o
+obj-$(CONFIG_GOLDFISH_TIMER)		+= timer-goldfish.o
diff --git a/drivers/clocksource/timer-goldfish.c b/drivers/clocksource/timer-goldfish.c
new file mode 100644
index 000000000000..9bf9ac8c4f5c
--- /dev/null
+++ b/drivers/clocksource/timer-goldfish.c
@@ -0,0 +1,139 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/interrupt.h>
+#include <linux/ioport.h>
+#include <linux/clocksource.h>
+#include <linux/clockchips.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <clocksource/timer-goldfish.h>
+
+#define TIMER_TIME_LOW		0x00	/* get low bits of current time  */
+					/*   and update TIMER_TIME_HIGH  */
+#define TIMER_TIME_HIGH		0x04	/* get high bits of time at last */
+					/*   TIMER_TIME_LOW read         */
+#define TIMER_ALARM_LOW		0x08	/* set low bits of alarm and     */
+					/*   activate it                 */
+#define TIMER_ALARM_HIGH	0x0c	/* set high bits of next alarm   */
+#define TIMER_IRQ_ENABLED	0x10
+#define TIMER_CLEAR_ALARM	0x14
+#define TIMER_ALARM_STATUS	0x18
+#define TIMER_CLEAR_INTERRUPT	0x1c
+
+/* goldfish endianness depends on CPU endianness */
+#ifdef CONFIG_CPU_BIG_ENDIAN
+#define goldfish_ioread32 ioread32be
+#define goldfish_iowrite32 iowrite32be
+#else
+#define goldfish_ioread32 ioread32
+#define goldfish_iowrite32 iowrite32
+#endif
+
+struct goldfish_timer {
+	struct clock_event_device ced;
+	struct resource res;
+	void __iomem *base;
+	int irq;
+};
+
+static struct goldfish_timer *ced_to_gf(struct clock_event_device *ced)
+{
+	return container_of(ced, struct goldfish_timer, ced);
+}
+
+static int goldfish_timer_set_oneshot(struct clock_event_device *evt)
+{
+	struct goldfish_timer *timerdrv = ced_to_gf(evt);
+	void __iomem *base = timerdrv->base;
+
+	goldfish_iowrite32(0, base + TIMER_ALARM_HIGH);
+	goldfish_iowrite32(0, base + TIMER_ALARM_LOW);
+	goldfish_iowrite32(1, base + TIMER_IRQ_ENABLED);
+
+	return 0;
+}
+
+static int goldfish_timer_shutdown(struct clock_event_device *evt)
+{
+	struct goldfish_timer *timerdrv = ced_to_gf(evt);
+	void __iomem *base = timerdrv->base;
+
+	goldfish_iowrite32(0, base + TIMER_IRQ_ENABLED);
+
+	return 0;
+}
+
+static int goldfish_timer_next_event(unsigned long delta,
+				     struct clock_event_device *evt)
+{
+	struct goldfish_timer *timerdrv = ced_to_gf(evt);
+	void __iomem *base = timerdrv->base;
+	u64 now;
+
+	goldfish_iowrite32(1, base + TIMER_CLEAR_INTERRUPT);
+
+	/*
+	 * time_low: get low bits of current time and update time_high
+	 * time_high: get high bits of time at last time_low read
+	 */
+	now = goldfish_ioread32(base + TIMER_TIME_LOW);
+	now += (u64)goldfish_ioread32(base + TIMER_TIME_HIGH) << 32;
+
+	now += delta;
+
+	goldfish_iowrite32(upper_32_bits(now), base + TIMER_ALARM_HIGH);
+	goldfish_iowrite32(lower_32_bits(now), base + TIMER_ALARM_LOW);
+
+	return 0;
+}
+
+static irqreturn_t golfish_timer_tick(int irq, void *dev_id)
+{
+	struct clock_event_device *evt = dev_id;
+
+	evt->event_handler(evt);
+
+	return IRQ_HANDLED;
+}
+
+void __init goldfish_timer_init(int irq, void __iomem *base)
+{
+	struct goldfish_timer *timerdrv;
+	int ret;
+
+	timerdrv = kzalloc(sizeof(*timerdrv), GFP_KERNEL);
+	if (!timerdrv)
+		return;
+
+	timerdrv->base = base;
+	timerdrv->irq = irq;
+
+	timerdrv->ced = (struct clock_event_device){
+		.name			= "goldfish_timer",
+		.features		= CLOCK_EVT_FEAT_ONESHOT,
+		.set_state_shutdown	= goldfish_timer_shutdown,
+		.set_state_oneshot      = goldfish_timer_set_oneshot,
+		.set_next_event		= goldfish_timer_next_event,
+		.shift			= 32,
+	};
+	timerdrv->res = (struct resource){
+		.name  = "goldfish_timer",
+		.start = (unsigned long)base,
+		.end   = (unsigned long)base + 0xfff,
+	};
+
+	if (request_resource(&iomem_resource, &timerdrv->res)) {
+		pr_err("Cannot allocate goldfish-timer resource\n");
+		return;
+	}
+
+	ret = request_irq(timerdrv->irq, golfish_timer_tick, IRQF_TIMER,
+			  "goldfish_timer", &timerdrv->ced);
+	if (ret) {
+		pr_err("Couldn't register goldfish-timer interrupt\n");
+		return;
+	}
+
+	clockevents_config_and_register(&timerdrv->ced, NSEC_PER_SEC,
+					1, 0xffffffff);
+}
diff --git a/include/clocksource/timer-goldfish.h b/include/clocksource/timer-goldfish.h
new file mode 100644
index 000000000000..b237267844f1
--- /dev/null
+++ b/include/clocksource/timer-goldfish.h
@@ -0,0 +1,11 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * goldfish-timer clocksource
+ */
+
+#ifndef _CLOCKSOURCE_GOLDFISH_TIMER_H
+#define _CLOCKSOURCE_GOLDFISH_TIMER_H
+
+extern void goldfish_timer_init(int irq, void __iomem *base);
+
+#endif /* _CLOCKSOURCE_GOLDFISH_TIMER_H */
-- 
2.34.1

[PATCH v8 4/4] m68k: introduce a virtual m68k machine

[Laurent Vivier]

This machine allows to have up to 3.2 GiB and 128 Virtio devices.

It is based on android goldfish devices.

Signed-off-by: Laurent Vivier <laurent@vivier.eu>
---
 arch/m68k/Kbuild                           |   1 +
 arch/m68k/Kconfig.machine                  |  17 +++
 arch/m68k/configs/virt_defconfig           |  65 ++++++++++
 arch/m68k/include/asm/config.h             |   2 +
 arch/m68k/include/asm/irq.h                |   3 +-
 arch/m68k/include/asm/pgtable_mm.h         |   7 ++
 arch/m68k/include/asm/setup.h              |  44 +++++--
 arch/m68k/include/asm/virt.h               |  25 ++++
 arch/m68k/include/uapi/asm/bootinfo-virt.h |  18 +++
 arch/m68k/include/uapi/asm/bootinfo.h      |   1 +
 arch/m68k/kernel/Makefile                  |   1 +
 arch/m68k/kernel/head.S                    |  31 +++++
 arch/m68k/kernel/setup_mm.c                |   7 ++
 arch/m68k/mm/kmap.c                        |  23 ++--
 arch/m68k/virt/Makefile                    |   6 +
 arch/m68k/virt/config.c                    | 119 ++++++++++++++++++
 arch/m68k/virt/ints.c                      | 133 +++++++++++++++++++++
 arch/m68k/virt/platform.c                  |  72 +++++++++++
 18 files changed, 557 insertions(+), 18 deletions(-)
 create mode 100644 arch/m68k/configs/virt_defconfig
 create mode 100644 arch/m68k/include/asm/virt.h
 create mode 100644 arch/m68k/include/uapi/asm/bootinfo-virt.h
 create mode 100644 arch/m68k/virt/Makefile
 create mode 100644 arch/m68k/virt/config.c
 create mode 100644 arch/m68k/virt/ints.c
 create mode 100644 arch/m68k/virt/platform.c

diff --git a/arch/m68k/Kbuild b/arch/m68k/Kbuild
index 18abb35c26a1..7762af9f6def 100644
--- a/arch/m68k/Kbuild
+++ b/arch/m68k/Kbuild
@@ -17,3 +17,4 @@ obj-$(CONFIG_M68060)		+= ifpsp060/
 obj-$(CONFIG_M68KFPU_EMU)	+= math-emu/
 obj-$(CONFIG_M68000)		+= 68000/
 obj-$(CONFIG_COLDFIRE)		+= coldfire/
+obj-$(CONFIG_VIRT)		+= virt/
diff --git a/arch/m68k/Kconfig.machine b/arch/m68k/Kconfig.machine
index eeab4f3e6c19..13b900bf8eb8 100644
--- a/arch/m68k/Kconfig.machine
+++ b/arch/m68k/Kconfig.machine
@@ -149,6 +149,23 @@ config SUN3
 
 	  If you don't want to compile a kernel exclusively for a Sun 3, say N.
 
+config VIRT
+	bool "Virtual M68k Machine support"
+	depends on MMU
+	select GENERIC_CLOCKEVENTS
+	select M68040
+	select MMU_MOTOROLA if MMU
+	select RTC_CLASS
+	select GOLDFISH
+	select RTC_DRV_GOLDFISH
+	select GOLDFISH_TIMER
+	select GOLDFISH_TTY
+	select TTY
+	select VIRTIO_MMIO
+	help
+	  This options enable a pure virtual machine based on m68k,
+	  VIRTIO MMIO devices and GOLDFISH interfaces (TTY, RTC, PIC)
+
 config PILOT
 	bool
 
diff --git a/arch/m68k/configs/virt_defconfig b/arch/m68k/configs/virt_defconfig
new file mode 100644
index 000000000000..462e51ef69eb
--- /dev/null
+++ b/arch/m68k/configs/virt_defconfig
@@ -0,0 +1,65 @@
+CONFIG_LOCALVERSION="-virt"
+CONFIG_SYSVIPC=y
+CONFIG_CGROUPS=y
+CONFIG_BLK_CGROUP=y
+CONFIG_CGROUP_SCHED=y
+CONFIG_CGROUP_PIDS=y
+CONFIG_CGROUP_RDMA=y
+CONFIG_CGROUP_FREEZER=y
+CONFIG_CGROUP_DEVICE=y
+CONFIG_CGROUP_CPUACCT=y
+CONFIG_VIRT=y
+CONFIG_PROC_HARDWARE=y
+CONFIG_PARTITION_ADVANCED=y
+CONFIG_AMIGA_PARTITION=y
+CONFIG_ATARI_PARTITION=y
+CONFIG_MAC_PARTITION=y
+CONFIG_BSD_DISKLABEL=y
+CONFIG_MINIX_SUBPARTITION=y
+CONFIG_SOLARIS_X86_PARTITION=y
+CONFIG_UNIXWARE_DISKLABEL=y
+CONFIG_LDM_PARTITION=y
+CONFIG_LDM_DEBUG=y
+CONFIG_SUN_PARTITION=y
+CONFIG_SYSV68_PARTITION=y
+CONFIG_NET=y
+CONFIG_PACKET=y
+CONFIG_UNIX=y
+CONFIG_INET=y
+CONFIG_IP_PNP=y
+CONFIG_IP_PNP_DHCP=y
+CONFIG_IP_PNP_BOOTP=y
+CONFIG_CGROUP_NET_PRIO=y
+CONFIG_CGROUP_NET_CLASSID=y
+CONFIG_NET_9P=y
+CONFIG_NET_9P_VIRTIO=y
+CONFIG_DEVTMPFS=y
+CONFIG_BLK_DEV_LOOP=y
+CONFIG_BLK_DEV_RAM=y
+CONFIG_VIRTIO_BLK=y
+CONFIG_SCSI=y
+CONFIG_BLK_DEV_SR=y
+CONFIG_SCSI_VIRTIO=y
+CONFIG_NETDEVICES=y
+CONFIG_VIRTIO_NET=y
+CONFIG_INPUT_MOUSEDEV=y
+CONFIG_INPUT_EVDEV=y
+CONFIG_VIRTIO_CONSOLE=y
+CONFIG_HW_RANDOM_VIRTIO=y
+CONFIG_DRM=y
+CONFIG_DRM_VIRTIO_GPU=y
+CONFIG_FB=y
+CONFIG_VIRT_DRIVERS=y
+CONFIG_VIRTIO_INPUT=y
+CONFIG_EXT4_FS=y
+CONFIG_AUTOFS_FS=y
+CONFIG_ISO9660_FS=y
+CONFIG_JOLIET=y
+CONFIG_ZISOFS=y
+CONFIG_UDF_FS=y
+CONFIG_TMPFS=y
+CONFIG_TMPFS_POSIX_ACL=y
+CONFIG_9P_FS=y
+CONFIG_9P_FS_POSIX_ACL=y
+CONFIG_9P_FS_SECURITY=y
+CONFIG_EARLY_PRINTK=y
diff --git a/arch/m68k/include/asm/config.h b/arch/m68k/include/asm/config.h
index aae61070628b..b9dacc52f2c8 100644
--- a/arch/m68k/include/asm/config.h
+++ b/arch/m68k/include/asm/config.h
@@ -17,6 +17,7 @@ extern int mvme16x_parse_bootinfo(const struct bi_record *record);
 extern int mvme147_parse_bootinfo(const struct bi_record *record);
 extern int hp300_parse_bootinfo(const struct bi_record *record);
 extern int apollo_parse_bootinfo(const struct bi_record *record);
+extern int virt_parse_bootinfo(const struct bi_record *record);
 
 extern void config_amiga(void);
 extern void config_atari(void);
@@ -29,5 +30,6 @@ extern void config_bvme6000(void);
 extern void config_hp300(void);
 extern void config_q40(void);
 extern void config_sun3x(void);
+extern void config_virt(void);
 
 #endif /* _M68K_CONFIG_H */
diff --git a/arch/m68k/include/asm/irq.h b/arch/m68k/include/asm/irq.h
index 91dd493791d7..7829e955ca04 100644
--- a/arch/m68k/include/asm/irq.h
+++ b/arch/m68k/include/asm/irq.h
@@ -12,7 +12,8 @@
  */
 #if defined(CONFIG_COLDFIRE)
 #define NR_IRQS 256
-#elif defined(CONFIG_VME) || defined(CONFIG_SUN3) || defined(CONFIG_SUN3X)
+#elif defined(CONFIG_VME) || defined(CONFIG_SUN3) || \
+      defined(CONFIG_SUN3X) || defined(CONFIG_VIRT)
 #define NR_IRQS 200
 #elif defined(CONFIG_ATARI)
 #define NR_IRQS 141
diff --git a/arch/m68k/include/asm/pgtable_mm.h b/arch/m68k/include/asm/pgtable_mm.h
index 143ba7de9bda..9b4e2fe2ac82 100644
--- a/arch/m68k/include/asm/pgtable_mm.h
+++ b/arch/m68k/include/asm/pgtable_mm.h
@@ -80,6 +80,9 @@
 #elif defined(CONFIG_COLDFIRE)
 #define KMAP_START	0xe0000000
 #define KMAP_END	0xf0000000
+#elif defined(CONFIG_VIRT)
+#define	KMAP_START	0xdf000000
+#define	KMAP_END	0xff000000
 #else
 #define	KMAP_START	0xd0000000
 #define	KMAP_END	0xf0000000
@@ -92,6 +95,10 @@ extern unsigned long m68k_vmalloc_end;
 #elif defined(CONFIG_COLDFIRE)
 #define VMALLOC_START	0xd0000000
 #define VMALLOC_END	0xe0000000
+#elif defined(CONFIG_VIRT)
+#define VMALLOC_OFFSET	PAGE_SIZE
+#define VMALLOC_START (((unsigned long) high_memory + VMALLOC_OFFSET) & ~(VMALLOC_OFFSET-1))
+#define VMALLOC_END     KMAP_START
 #else
 /* Just any arbitrary offset to the start of the vmalloc VM area: the
  * current 8MB value just means that there will be a 8MB "hole" after the
diff --git a/arch/m68k/include/asm/setup.h b/arch/m68k/include/asm/setup.h
index 8f2023f8c1c4..2c99477aaf89 100644
--- a/arch/m68k/include/asm/setup.h
+++ b/arch/m68k/include/asm/setup.h
@@ -37,7 +37,8 @@ extern unsigned long m68k_machtype;
 #elif defined(CONFIG_ATARI) || defined(CONFIG_MAC) || defined(CONFIG_APOLLO) \
 	|| defined(CONFIG_MVME16x) || defined(CONFIG_BVME6000)               \
 	|| defined(CONFIG_HP300) || defined(CONFIG_Q40)                      \
-	|| defined(CONFIG_SUN3X) || defined(CONFIG_MVME147)
+	|| defined(CONFIG_SUN3X) || defined(CONFIG_MVME147)                  \
+	|| defined(CONFIG_VIRT)
 #  define MACH_IS_AMIGA (m68k_machtype == MACH_AMIGA)
 #else
 #  define MACH_AMIGA_ONLY
@@ -50,7 +51,8 @@ extern unsigned long m68k_machtype;
 #elif defined(CONFIG_AMIGA) || defined(CONFIG_MAC) || defined(CONFIG_APOLLO) \
 	|| defined(CONFIG_MVME16x) || defined(CONFIG_BVME6000)               \
 	|| defined(CONFIG_HP300) || defined(CONFIG_Q40)                      \
-	|| defined(CONFIG_SUN3X) || defined(CONFIG_MVME147)
+	|| defined(CONFIG_SUN3X) || defined(CONFIG_MVME147)                  \
+	|| defined(CONFIG_VIRT)
 #  define MACH_IS_ATARI (m68k_machtype == MACH_ATARI)
 #else
 #  define MACH_ATARI_ONLY
@@ -63,7 +65,8 @@ extern unsigned long m68k_machtype;
 #elif defined(CONFIG_AMIGA) || defined(CONFIG_ATARI) || defined(CONFIG_APOLLO) \
 	|| defined(CONFIG_MVME16x) || defined(CONFIG_BVME6000)                 \
 	|| defined(CONFIG_HP300) || defined(CONFIG_Q40)                        \
-	|| defined(CONFIG_SUN3X) || defined(CONFIG_MVME147)
+	|| defined(CONFIG_SUN3X) || defined(CONFIG_MVME147)                    \
+	|| defined(CONFIG_VIRT)
 #  define MACH_IS_MAC (m68k_machtype == MACH_MAC)
 #else
 #  define MACH_MAC_ONLY
@@ -84,7 +87,8 @@ extern unsigned long m68k_machtype;
 #elif defined(CONFIG_AMIGA) || defined(CONFIG_MAC) || defined(CONFIG_ATARI) \
 	|| defined(CONFIG_MVME16x) || defined(CONFIG_BVME6000)              \
 	|| defined(CONFIG_HP300) || defined(CONFIG_Q40)                     \
-	|| defined(CONFIG_SUN3X) || defined(CONFIG_MVME147)
+	|| defined(CONFIG_SUN3X) || defined(CONFIG_MVME147)                 \
+	|| defined(CONFIG_VIRT)
 #  define MACH_IS_APOLLO (m68k_machtype == MACH_APOLLO)
 #else
 #  define MACH_APOLLO_ONLY
@@ -97,7 +101,8 @@ extern unsigned long m68k_machtype;
 #elif defined(CONFIG_AMIGA) || defined(CONFIG_MAC) || defined(CONFIG_ATARI) \
 	|| defined(CONFIG_APOLLO) || defined(CONFIG_BVME6000)               \
 	|| defined(CONFIG_HP300) || defined(CONFIG_Q40)                     \
-	|| defined(CONFIG_SUN3X) || defined(CONFIG_MVME16x)
+	|| defined(CONFIG_SUN3X) || defined(CONFIG_MVME16x)                 \
+	|| defined(CONFIG_VIRT)
 #  define MACH_IS_MVME147 (m68k_machtype == MACH_MVME147)
 #else
 #  define MACH_MVME147_ONLY
@@ -110,7 +115,8 @@ extern unsigned long m68k_machtype;
 #elif defined(CONFIG_AMIGA) || defined(CONFIG_MAC) || defined(CONFIG_ATARI) \
 	|| defined(CONFIG_APOLLO) || defined(CONFIG_BVME6000)               \
 	|| defined(CONFIG_HP300) || defined(CONFIG_Q40)                     \
-	|| defined(CONFIG_SUN3X) || defined(CONFIG_MVME147)
+	|| defined(CONFIG_SUN3X) || defined(CONFIG_MVME147)                 \
+	|| defined(CONFIG_VIRT)
 #  define MACH_IS_MVME16x (m68k_machtype == MACH_MVME16x)
 #else
 #  define MACH_MVME16x_ONLY
@@ -123,7 +129,8 @@ extern unsigned long m68k_machtype;
 #elif defined(CONFIG_AMIGA) || defined(CONFIG_MAC) || defined(CONFIG_ATARI) \
 	|| defined(CONFIG_APOLLO) || defined(CONFIG_MVME16x)                \
 	|| defined(CONFIG_HP300) || defined(CONFIG_Q40)                     \
-	|| defined(CONFIG_SUN3X) || defined(CONFIG_MVME147)
+	|| defined(CONFIG_SUN3X) || defined(CONFIG_MVME147)                 \
+	|| defined(CONFIG_VIRT)
 #  define MACH_IS_BVME6000 (m68k_machtype == MACH_BVME6000)
 #else
 #  define MACH_BVME6000_ONLY
@@ -136,7 +143,8 @@ extern unsigned long m68k_machtype;
 #elif defined(CONFIG_AMIGA) || defined(CONFIG_MAC) || defined(CONFIG_ATARI) \
 	|| defined(CONFIG_APOLLO) || defined(CONFIG_MVME16x) \
 	|| defined(CONFIG_BVME6000) || defined(CONFIG_Q40) \
-	|| defined(CONFIG_SUN3X) || defined(CONFIG_MVME147)
+	|| defined(CONFIG_SUN3X) || defined(CONFIG_MVME147) \
+	|| defined(CONFIG_VIRT)
 #  define MACH_IS_HP300 (m68k_machtype == MACH_HP300)
 #else
 #  define MACH_HP300_ONLY
@@ -149,7 +157,8 @@ extern unsigned long m68k_machtype;
 #elif defined(CONFIG_AMIGA) || defined(CONFIG_MAC) || defined(CONFIG_ATARI) \
 	|| defined(CONFIG_APOLLO) || defined(CONFIG_MVME16x)                \
 	|| defined(CONFIG_BVME6000) || defined(CONFIG_HP300)                \
-	|| defined(CONFIG_SUN3X) || defined(CONFIG_MVME147)
+	|| defined(CONFIG_SUN3X) || defined(CONFIG_MVME147)                 \
+	|| defined(CONFIG_VIRT)
 #  define MACH_IS_Q40 (m68k_machtype == MACH_Q40)
 #else
 #  define MACH_Q40_ONLY
@@ -162,7 +171,8 @@ extern unsigned long m68k_machtype;
 #elif defined(CONFIG_AMIGA) || defined(CONFIG_MAC) || defined(CONFIG_ATARI) \
 	|| defined(CONFIG_APOLLO) || defined(CONFIG_MVME16x)                \
 	|| defined(CONFIG_BVME6000) || defined(CONFIG_HP300)                \
-	|| defined(CONFIG_Q40) || defined(CONFIG_MVME147)
+	|| defined(CONFIG_Q40) || defined(CONFIG_MVME147)                   \
+	|| defined(CONFIG_VIRT)
 #  define MACH_IS_SUN3X (m68k_machtype == MACH_SUN3X)
 #else
 #  define CONFIG_SUN3X_ONLY
@@ -170,6 +180,20 @@ extern unsigned long m68k_machtype;
 #  define MACH_TYPE (MACH_SUN3X)
 #endif
 
+#if !defined(CONFIG_VIRT)
+#  define MACH_IS_VIRT (0)
+#elif defined(CONFIG_AMIGA) || defined(CONFIG_MAC) || defined(CONFIG_ATARI) \
+	|| defined(CONFIG_APOLLO) || defined(CONFIG_MVME16x)                \
+	|| defined(CONFIG_BVME6000) || defined(CONFIG_HP300)                \
+	|| defined(CONFIG_Q40) || defined(CONFIG_SUN3X)                     \
+	|| defined(CONFIG_MVME147)
+#  define MACH_IS_VIRT (m68k_machtype == MACH_VIRT)
+#else
+#  define MACH_VIRT_ONLY
+#  define MACH_IS_VIRT (1)
+#  define MACH_TYPE (MACH_VIRT)
+#endif
+
 #ifndef MACH_TYPE
 #  define MACH_TYPE (m68k_machtype)
 #endif
diff --git a/arch/m68k/include/asm/virt.h b/arch/m68k/include/asm/virt.h
new file mode 100644
index 000000000000..87647c17afd7
--- /dev/null
+++ b/arch/m68k/include/asm/virt.h
@@ -0,0 +1,25 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __ASM_VIRT_H
+#define __ASM_VIRT_H
+
+#define NUM_VIRT_SOURCES 200
+
+struct virt_booter_device_data {
+	unsigned long mmio;
+	unsigned long irq;
+};
+
+struct virt_booter_data {
+	unsigned long qemu_version;
+	struct virt_booter_device_data pic;
+	struct virt_booter_device_data rtc;
+	struct virt_booter_device_data tty;
+	struct virt_booter_device_data ctrl;
+	struct virt_booter_device_data virtio;
+};
+
+extern struct virt_booter_data virt_bi_data;
+
+extern void __init virt_init_IRQ(void);
+
+#endif
diff --git a/arch/m68k/include/uapi/asm/bootinfo-virt.h b/arch/m68k/include/uapi/asm/bootinfo-virt.h
new file mode 100644
index 000000000000..e4db7e2213ab
--- /dev/null
+++ b/arch/m68k/include/uapi/asm/bootinfo-virt.h
@@ -0,0 +1,18 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+/*
+ * asm/bootinfo-virt.h -- Virtual-m68k-specific boot information definitions
+ */
+
+#ifndef _UAPI_ASM_M68K_BOOTINFO_VIRT_H
+#define _UAPI_ASM_M68K_BOOTINFO_VIRT_H
+
+#define BI_VIRT_QEMU_VERSION	0x8000
+#define BI_VIRT_GF_PIC_BASE	0x8001
+#define BI_VIRT_GF_RTC_BASE	0x8002
+#define BI_VIRT_GF_TTY_BASE	0x8003
+#define BI_VIRT_VIRTIO_BASE	0x8004
+#define BI_VIRT_CTRL_BASE	0x8005
+
+#define VIRT_BOOTI_VERSION	MK_BI_VERSION(2, 0)
+
+#endif /* _UAPI_ASM_M68K_BOOTINFO_MAC_H */
diff --git a/arch/m68k/include/uapi/asm/bootinfo.h b/arch/m68k/include/uapi/asm/bootinfo.h
index 38d3140381fa..203d9cbf9630 100644
--- a/arch/m68k/include/uapi/asm/bootinfo.h
+++ b/arch/m68k/include/uapi/asm/bootinfo.h
@@ -83,6 +83,7 @@ struct mem_info {
 #define MACH_SUN3X		11
 #define MACH_M54XX		12
 #define MACH_M5441X		13
+#define MACH_VIRT		14
 
 
     /*
diff --git a/arch/m68k/kernel/Makefile b/arch/m68k/kernel/Makefile
index dbac7f8743fc..c0833da6a2ca 100644
--- a/arch/m68k/kernel/Makefile
+++ b/arch/m68k/kernel/Makefile
@@ -11,6 +11,7 @@ extra-$(CONFIG_VME)	:= head.o
 extra-$(CONFIG_HP300)	:= head.o
 extra-$(CONFIG_Q40)	:= head.o
 extra-$(CONFIG_SUN3X)	:= head.o
+extra-$(CONFIG_VIRT)	:= head.o
 extra-$(CONFIG_SUN3)	:= sun3-head.o
 extra-y			+= vmlinux.lds
 
diff --git a/arch/m68k/kernel/head.S b/arch/m68k/kernel/head.S
index 493c95db0e51..9e812d8606be 100644
--- a/arch/m68k/kernel/head.S
+++ b/arch/m68k/kernel/head.S
@@ -262,6 +262,7 @@
 #include <asm/bootinfo-hp300.h>
 #include <asm/bootinfo-mac.h>
 #include <asm/bootinfo-q40.h>
+#include <asm/bootinfo-virt.h>
 #include <asm/bootinfo-vme.h>
 #include <asm/setup.h>
 #include <asm/entry.h>
@@ -534,6 +535,7 @@ func_define	putn,1
 #define is_not_apollo(lab) cmpl &MACH_APOLLO,%pc@(m68k_machtype); jne lab
 #define is_not_q40(lab) cmpl &MACH_Q40,%pc@(m68k_machtype); jne lab
 #define is_not_sun3x(lab) cmpl &MACH_SUN3X,%pc@(m68k_machtype); jne lab
+#define is_not_virt(lab) cmpl &MACH_VIRT,%pc@(m68k_machtype); jne lab
 
 #define hasnt_leds(lab) cmpl &MACH_HP300,%pc@(m68k_machtype); \
 			jeq 42f; \
@@ -647,6 +649,14 @@ ENTRY(__start)
 L(test_notmac):
 #endif /* CONFIG_MAC */
 
+#ifdef CONFIG_VIRT
+	is_not_virt(L(test_notvirt))
+
+	get_bi_record BI_VIRT_GF_TTY_BASE
+	lea	%pc@(L(virt_gf_tty_base)),%a1
+	movel	%a0@,%a1@
+L(test_notvirt):
+#endif /* CONFIG_VIRT */
 
 /*
  * There are ultimately two pieces of information we want for all kinds of
@@ -1237,6 +1247,13 @@ L(mmu_init_not_mac):
 L(notsun3x):
 #endif
 
+#ifdef CONFIG_VIRT
+	is_not_virt(L(novirt))
+	mmu_map_tt	#1,#0xFF000000,#0x01000000,#_PAGE_NOCACHE_S
+	jbra    L(mmu_init_done)
+L(novirt):
+#endif
+
 #ifdef CONFIG_APOLLO
 	is_not_apollo(L(notapollo))
 
@@ -3186,6 +3203,14 @@ func_start	serial_putc,%d0/%d1/%a0/%a1
 3:
 #endif
 
+#ifdef CONFIG_VIRT
+	is_not_virt(1f)
+
+	movel L(virt_gf_tty_base),%a1
+	movel %d0,%a1@(GF_PUT_CHAR)
+1:
+#endif
+
 L(serial_putc_done):
 func_return	serial_putc
 
@@ -3865,3 +3890,9 @@ q40_mem_cptr:
 L(q40_do_debug):
 	.long	0
 #endif
+
+#if defined(CONFIG_VIRT)
+GF_PUT_CHAR = 0x00
+L(virt_gf_tty_base):
+	.long 0
+#endif /* CONFIG_VIRT */
diff --git a/arch/m68k/kernel/setup_mm.c b/arch/m68k/kernel/setup_mm.c
index 226dc3750397..b4ece3b05504 100644
--- a/arch/m68k/kernel/setup_mm.c
+++ b/arch/m68k/kernel/setup_mm.c
@@ -182,6 +182,8 @@ static void __init m68k_parse_bootinfo(const struct bi_record *record)
 				unknown = hp300_parse_bootinfo(record);
 			else if (MACH_IS_APOLLO)
 				unknown = apollo_parse_bootinfo(record);
+			else if (MACH_IS_VIRT)
+				unknown = virt_parse_bootinfo(record);
 			else
 				unknown = 1;
 		}
@@ -312,6 +314,11 @@ void __init setup_arch(char **cmdline_p)
 		cf_mmu_context_init();
 		config_BSP(NULL, 0);
 		break;
+#endif
+#ifdef CONFIG_VIRT
+	case MACH_VIRT:
+		config_virt();
+		break;
 #endif
 	default:
 		panic("No configuration setup");
diff --git a/arch/m68k/mm/kmap.c b/arch/m68k/mm/kmap.c
index 20ddf71b43d0..39729f40d106 100644
--- a/arch/m68k/mm/kmap.c
+++ b/arch/m68k/mm/kmap.c
@@ -179,6 +179,12 @@ void __iomem *__ioremap(unsigned long physaddr, unsigned long size, int cachefla
 			return (void __iomem *)physaddr;
 	}
 #endif
+#ifdef CONFIG_VIRT
+	if (MACH_IS_VIRT) {
+		if (physaddr >= 0xff000000 && cacheflag == IOMAP_NOCACHE_SER)
+			return (void __iomem *)physaddr;
+	}
+#endif
 #ifdef CONFIG_COLDFIRE
 	if (__cf_internalio(physaddr))
 		return (void __iomem *) physaddr;
@@ -292,18 +298,21 @@ EXPORT_SYMBOL(__ioremap);
  */
 void iounmap(void __iomem *addr)
 {
-#ifdef CONFIG_AMIGA
-	if ((!MACH_IS_AMIGA) ||
-	    (((unsigned long)addr < 0x40000000) ||
-	     ((unsigned long)addr > 0x60000000)))
-			free_io_area((__force void *)addr);
-#else
+#if defined(CONFIG_AMIGA)
+	if (MACH_IS_AMIGA &&
+	    ((unsigned long)addr >= 0x40000000) &&
+	    ((unsigned long)addr < 0x60000000))
+		return;
+#endif
+#if defined(CONFIG_VIRT)
+	if (MACH_IS_VIRT && (unsigned long)addr >= 0xff000000)
+		return;
+#endif
 #ifdef CONFIG_COLDFIRE
 	if (cf_internalio(addr))
 		return;
 #endif
 	free_io_area((__force void *)addr);
-#endif
 }
 EXPORT_SYMBOL(iounmap);
 
diff --git a/arch/m68k/virt/Makefile b/arch/m68k/virt/Makefile
new file mode 100644
index 000000000000..54b9b2866654
--- /dev/null
+++ b/arch/m68k/virt/Makefile
@@ -0,0 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Makefile for Linux arch/m68k/virt source directory
+#
+
+obj-y		:= config.o ints.o platform.o
diff --git a/arch/m68k/virt/config.c b/arch/m68k/virt/config.c
new file mode 100644
index 000000000000..e92a22dad1bc
--- /dev/null
+++ b/arch/m68k/virt/config.c
@@ -0,0 +1,119 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/serial_core.h>
+#include <clocksource/timer-goldfish.h>
+
+#include <asm/bootinfo.h>
+#include <asm/bootinfo-virt.h>
+#include <asm/byteorder.h>
+#include <asm/machdep.h>
+#include <asm/virt.h>
+#include <asm/config.h>
+
+struct virt_booter_data virt_bi_data;
+
+#define VIRT_CTRL_REG_FEATURES	0x00
+#define VIRT_CTRL_REG_CMD	0x04
+
+enum {
+	CMD_NOOP,
+	CMD_RESET,
+	CMD_HALT,
+	CMD_PANIC,
+};
+
+static void virt_get_model(char *str)
+{
+	/* str is 80 characters long */
+	sprintf(str, "QEMU Virtual M68K Machine (%u.%u.%u)",
+		(u8)(virt_bi_data.qemu_version >> 24),
+		(u8)(virt_bi_data.qemu_version >> 16),
+		(u8)(virt_bi_data.qemu_version >> 8));
+}
+
+static void virt_halt(void)
+{
+	void __iomem *base = (void *)virt_bi_data.ctrl.mmio;
+
+	iowrite32be(CMD_HALT, base + VIRT_CTRL_REG_CMD);
+	local_irq_disable();
+	while (1)
+		;
+}
+
+static void virt_reset(void)
+{
+	void __iomem *base = (void *)virt_bi_data.ctrl.mmio;
+
+	iowrite32be(CMD_RESET, base + VIRT_CTRL_REG_CMD);
+	local_irq_disable();
+	while (1)
+		;
+}
+
+/*
+ * Parse a virtual-m68k-specific record in the bootinfo
+ */
+
+int __init virt_parse_bootinfo(const struct bi_record *record)
+{
+	int unknown = 0;
+	const void *data = record->data;
+
+	switch (be16_to_cpu(record->tag)) {
+	case BI_VIRT_QEMU_VERSION:
+		virt_bi_data.qemu_version = be32_to_cpup(data);
+		break;
+	case BI_VIRT_GF_PIC_BASE:
+		virt_bi_data.pic.mmio = be32_to_cpup(data);
+		data += 4;
+		virt_bi_data.pic.irq = be32_to_cpup(data);
+		break;
+	case BI_VIRT_GF_RTC_BASE:
+		virt_bi_data.rtc.mmio = be32_to_cpup(data);
+		data += 4;
+		virt_bi_data.rtc.irq = be32_to_cpup(data);
+		break;
+	case BI_VIRT_GF_TTY_BASE:
+		virt_bi_data.tty.mmio = be32_to_cpup(data);
+		data += 4;
+		virt_bi_data.tty.irq = be32_to_cpup(data);
+		break;
+	case BI_VIRT_CTRL_BASE:
+		virt_bi_data.ctrl.mmio = be32_to_cpup(data);
+		data += 4;
+		virt_bi_data.ctrl.irq = be32_to_cpup(data);
+		break;
+	case BI_VIRT_VIRTIO_BASE:
+		virt_bi_data.virtio.mmio = be32_to_cpup(data);
+		data += 4;
+		virt_bi_data.virtio.irq = be32_to_cpup(data);
+		break;
+	default:
+		unknown = 1;
+		break;
+	}
+	return unknown;
+}
+
+static void __init virt_sched_init(void)
+{
+	goldfish_timer_init(virt_bi_data.rtc.irq,
+			    (void *)virt_bi_data.rtc.mmio);
+}
+
+void __init config_virt(void)
+{
+	char earlycon[24];
+
+	snprintf(earlycon, sizeof(earlycon), "early_gf_tty,0x%08lx",
+		 virt_bi_data.tty.mmio);
+	setup_earlycon(earlycon);
+
+	mach_init_IRQ = virt_init_IRQ;
+	mach_sched_init = virt_sched_init;
+	mach_get_model = virt_get_model;
+	mach_reset = virt_reset;
+	mach_halt = virt_halt;
+	mach_power_off = virt_halt;
+}
diff --git a/arch/m68k/virt/ints.c b/arch/m68k/virt/ints.c
new file mode 100644
index 000000000000..ccc01370e320
--- /dev/null
+++ b/arch/m68k/virt/ints.c
@@ -0,0 +1,133 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/delay.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/sched/debug.h>
+#include <linux/types.h>
+
+#include <asm/hwtest.h>
+#include <asm/irq.h>
+#include <asm/irq_regs.h>
+#include <asm/virt.h>
+
+#define GFPIC_REG_IRQ_PENDING           0x04
+#define GFPIC_REG_IRQ_DISABLE_ALL       0x08
+#define GFPIC_REG_IRQ_DISABLE           0x0c
+#define GFPIC_REG_IRQ_ENABLE            0x10
+
+extern void show_registers(struct pt_regs *);
+
+/*
+ * 6 goldfish-pic for CPU IRQ #1 to IRQ #6
+ * CPU IRQ #1 -> PIC #1
+ *               IRQ #1 to IRQ #31 -> unused
+ *               IRQ #32 -> goldfish-tty
+ * CPU IRQ #2 -> PIC #2
+ *               IRQ #1 to IRQ #32 -> virtio-mmio from 1 to 32
+ * CPU IRQ #3 -> PIC #3
+ *               IRQ #1 to IRQ #32 -> virtio-mmio from 33 to 64
+ * CPU IRQ #4 -> PIC #4
+ *               IRQ #1 to IRQ #32 -> virtio-mmio from 65 to 96
+ * CPU IRQ #5 -> PIC #5
+ *               IRQ #1 to IRQ #32 -> virtio-mmio from 97 to 128
+ * CPU IRQ #6 -> PIC #6
+ *               IRQ #1 -> goldfish-timer
+ *               IRQ #2 -> goldfish-rtc
+ *               IRQ #3 to IRQ #32 -> unused
+ * CPU IRQ #7 -> NMI
+ */
+
+static u32 gfpic_read(int pic, int reg)
+{
+	void __iomem *base = (void *)(virt_bi_data.pic.mmio + pic * 0x1000);
+
+	return ioread32be(base + reg);
+}
+
+static void gfpic_write(u32 value, int pic, int reg)
+{
+	void __iomem *base = (void *)(virt_bi_data.pic.mmio + pic * 0x1000);
+
+	iowrite32be(value, base + reg);
+}
+
+#define GF_PIC(irq) ((irq - IRQ_USER) / 32)
+#define GF_IRQ(irq) ((irq - IRQ_USER) % 32)
+
+static void virt_irq_enable(struct irq_data *data)
+{
+	gfpic_write(1 << GF_IRQ(data->irq), GF_PIC(data->irq),
+		    GFPIC_REG_IRQ_ENABLE);
+}
+
+static void virt_irq_disable(struct irq_data *data)
+{
+	gfpic_write(1 << GF_IRQ(data->irq), GF_PIC(data->irq),
+		    GFPIC_REG_IRQ_DISABLE);
+}
+
+static unsigned int virt_irq_startup(struct irq_data *data)
+{
+	virt_irq_enable(data);
+	return 0;
+}
+
+static irqreturn_t virt_nmi_handler(int irq, void *dev_id)
+{
+	static volatile int in_nmi;
+
+	if (in_nmi)
+		return IRQ_HANDLED;
+	in_nmi = 1;
+
+	pr_warn("Non-Maskable Interrupt\n");
+	show_registers(get_irq_regs());
+
+	in_nmi = 0;
+	return IRQ_HANDLED;
+}
+
+static struct irq_chip virt_irq_chip = {
+	.name		= "virt",
+	.irq_enable	= virt_irq_enable,
+	.irq_disable	= virt_irq_disable,
+	.irq_startup	= virt_irq_startup,
+	.irq_shutdown	= virt_irq_disable,
+};
+
+static void goldfish_pic_irq(struct irq_desc *desc)
+{
+	u32 irq_pending;
+	int irq_num;
+	int pic = desc->irq_data.irq - 1;
+
+	irq_pending = gfpic_read(pic, GFPIC_REG_IRQ_PENDING);
+	irq_num = IRQ_USER + pic * 32;
+
+	do {
+		if (irq_pending & 1)
+			generic_handle_irq(irq_num);
+		++irq_num;
+		irq_pending >>= 1;
+	} while (irq_pending);
+}
+
+void __init virt_init_IRQ(void)
+{
+	int i;
+
+	m68k_setup_irq_controller(&virt_irq_chip, handle_simple_irq, IRQ_USER,
+				  NUM_VIRT_SOURCES - IRQ_USER);
+
+	for (i = 0; i < 6; i++) {
+		irq_set_chained_handler(virt_bi_data.pic.irq + i,
+					goldfish_pic_irq);
+	}
+
+	if (request_irq(IRQ_AUTO_7, virt_nmi_handler, 0, "NMI",
+			virt_nmi_handler))
+		pr_err("Couldn't register NMI\n");
+}
diff --git a/arch/m68k/virt/platform.c b/arch/m68k/virt/platform.c
new file mode 100644
index 000000000000..c16158e7a9ca
--- /dev/null
+++ b/arch/m68k/virt/platform.c
@@ -0,0 +1,72 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/platform_device.h>
+#include <linux/interrupt.h>
+#include <asm/virt.h>
+#include <asm/irq.h>
+
+#define VIRTIO_BUS_NB	128
+
+static int __init virt_virtio_init(int id)
+{
+	const struct resource res[] = {
+		DEFINE_RES_MEM(virt_bi_data.virtio.mmio + id * 0x200, 0x200),
+		DEFINE_RES_IRQ(virt_bi_data.virtio.irq + id),
+	};
+	struct platform_device *pdev;
+
+	pdev = platform_device_register_simple("virtio-mmio", id,
+					       res, ARRAY_SIZE(res));
+	if (IS_ERR(pdev))
+		return PTR_ERR(pdev);
+
+	return 0;
+}
+
+static int __init virt_platform_init(void)
+{
+	const struct resource goldfish_tty_res[] = {
+		DEFINE_RES_MEM(virt_bi_data.tty.mmio, 1),
+		DEFINE_RES_IRQ(virt_bi_data.tty.irq),
+	};
+	/* this is the second gf-rtc, the first one is used by the scheduler */
+	const struct resource goldfish_rtc_res[] = {
+		DEFINE_RES_MEM(virt_bi_data.rtc.mmio + 0x1000, 0x1000),
+		DEFINE_RES_IRQ(virt_bi_data.rtc.irq + 1),
+	};
+	extern unsigned long min_low_pfn;
+	struct platform_device *pdev;
+	int i;
+
+	if (!MACH_IS_VIRT)
+		return -ENODEV;
+
+	/* We need this to have DMA'able memory provided to goldfish-tty */
+	min_low_pfn = 0;
+
+	pdev = platform_device_register_simple("goldfish_tty",
+					       PLATFORM_DEVID_NONE,
+					       goldfish_tty_res,
+					       ARRAY_SIZE(goldfish_tty_res));
+	if (IS_ERR(pdev))
+		return PTR_ERR(pdev);
+
+	pdev = platform_device_register_simple("goldfish_rtc",
+					       PLATFORM_DEVID_NONE,
+					       goldfish_rtc_res,
+					       ARRAY_SIZE(goldfish_rtc_res));
+	if (IS_ERR(pdev))
+		return PTR_ERR(pdev);
+
+	for (i = 0; i < VIRTIO_BUS_NB; i++) {
+		int err;
+
+		err = virt_virtio_init(i);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
+arch_initcall(virt_platform_init);
-- 
2.34.1

Re: [PATCH v8 4/4] m68k: introduce a virtual m68k machine

[Geert Uytterhoeven]

Hi Laurent,

On Sat, Jan 15, 2022 at 8:33 PM Laurent Vivier <laurent@vivier.eu> wrote:
> This machine allows to have up to 3.2 GiB and 128 Virtio devices.
>
> It is based on android goldfish devices.
>
> Signed-off-by: Laurent Vivier <laurent@vivier.eu>

Thanks for your patch (the new versions keep on coming quickly).

> --- /dev/null
> +++ b/arch/m68k/virt/platform.c

> +static int __init virt_platform_init(void)
> +{
> +       const struct resource goldfish_tty_res[] = {
> +               DEFINE_RES_MEM(virt_bi_data.tty.mmio, 1),
> +               DEFINE_RES_IRQ(virt_bi_data.tty.irq),
> +       };
> +       /* this is the second gf-rtc, the first one is used by the scheduler */
> +       const struct resource goldfish_rtc_res[] = {
> +               DEFINE_RES_MEM(virt_bi_data.rtc.mmio + 0x1000, 0x1000),
> +               DEFINE_RES_IRQ(virt_bi_data.rtc.irq + 1),
> +       };
> +       extern unsigned long min_low_pfn;

checkpatch keeps on complaining.
#include <linux/memblock.h> instead?

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [PATCH v8 4/4] m68k: introduce a virtual m68k machine

[Laurent Vivier]

Le 15/01/2022 à 20:41, Geert Uytterhoeven a écrit :
> Hi Laurent,
> 
> On Sat, Jan 15, 2022 at 8:33 PM Laurent Vivier <laurent@vivier.eu> wrote:
>> This machine allows to have up to 3.2 GiB and 128 Virtio devices.
>>
>> It is based on android goldfish devices.
>>
>> Signed-off-by: Laurent Vivier <laurent@vivier.eu>
> 
> Thanks for your patch (the new versions keep on coming quickly).
> 
>> --- /dev/null
>> +++ b/arch/m68k/virt/platform.c
> 
>> +static int __init virt_platform_init(void)
>> +{
>> +       const struct resource goldfish_tty_res[] = {
>> +               DEFINE_RES_MEM(virt_bi_data.tty.mmio, 1),
>> +               DEFINE_RES_IRQ(virt_bi_data.tty.irq),
>> +       };
>> +       /* this is the second gf-rtc, the first one is used by the scheduler */
>> +       const struct resource goldfish_rtc_res[] = {
>> +               DEFINE_RES_MEM(virt_bi_data.rtc.mmio + 0x1000, 0x1000),
>> +               DEFINE_RES_IRQ(virt_bi_data.rtc.irq + 1),
>> +       };
>> +       extern unsigned long min_low_pfn;
> 
> checkpatch keeps on complaining.
> #include <linux/memblock.h> instead?

oh, yes, I didn't see it was defined here. Thank you.

I've updated my patch, the change will be in the next version.

Thanks,
Laurent

Re: [PATCH v8 2/4] rtc: goldfish: introduce goldfish_ioread32()/goldfish_iowrite32()

[Jiaxun Yang]

在2022年1月15日一月 下午7:32，Laurent Vivier写道：
> The goldfish device always uses the same endianness as the architecture
> using it:
> https://android.googlesource.com/platform/external/qemu/+/refs/heads/emu-master-dev/hw/timer/goldfish_timer.c#177
>
> On a big-endian machine, the device is also big-endian, on a
> little-endian machine the device is little-endian.
>
> So we need to use the right accessor to read/write values to the goldfish
> registers: ioread32()/iowrite32() on a little-endian machine,
> ioread32be()/iowrite32be() on a big-endian machine.
>
> This patch introduces goldfish_ioread32()/goldfish_iowrite32() that uses
> the expected accessor according to the machine endianness.
>
> Signed-off-by: Laurent Vivier <laurent@vivier.eu>

Acked-by: Jiaxun Yang <jiaxun.yang@flygoat.com>

> ---
>  drivers/rtc/rtc-goldfish.c | 39 +++++++++++++++++++++++---------------
>  1 file changed, 24 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/rtc/rtc-goldfish.c b/drivers/rtc/rtc-goldfish.c
> index 7ab95d052644..b0cae4729b03 100644
> --- a/drivers/rtc/rtc-goldfish.c
> +++ b/drivers/rtc/rtc-goldfish.c
> @@ -23,6 +23,15 @@
>  #define TIMER_ALARM_STATUS	0x18
>  #define TIMER_CLEAR_INTERRUPT	0x1c
> 
> +/* goldfish endianness depends on CPU endianness */
> +#ifdef CONFIG_CPU_BIG_ENDIAN
> +#define goldfish_ioread32 ioread32be
> +#define goldfish_iowrite32 iowrite32be
> +#else
> +#define goldfish_ioread32 ioread32
> +#define goldfish_iowrite32 iowrite32
> +#endif
> +
>  struct goldfish_rtc {
>  	void __iomem *base;
>  	int irq;
> @@ -41,8 +50,8 @@ static int goldfish_rtc_read_alarm(struct device *dev,
>  	rtcdrv = dev_get_drvdata(dev);
>  	base = rtcdrv->base;
> 
> -	rtc_alarm_low = readl(base + TIMER_ALARM_LOW);
> -	rtc_alarm_high = readl(base + TIMER_ALARM_HIGH);
> +	rtc_alarm_low = goldfish_ioread32(base + TIMER_ALARM_LOW);
> +	rtc_alarm_high = goldfish_ioread32(base + TIMER_ALARM_HIGH);
>  	rtc_alarm = (rtc_alarm_high << 32) | rtc_alarm_low;
> 
>  	do_div(rtc_alarm, NSEC_PER_SEC);
> @@ -50,7 +59,7 @@ static int goldfish_rtc_read_alarm(struct device *dev,
> 
>  	rtc_time64_to_tm(rtc_alarm, &alrm->time);
> 
> -	if (readl(base + TIMER_ALARM_STATUS))
> +	if (goldfish_ioread32(base + TIMER_ALARM_STATUS))
>  		alrm->enabled = 1;
>  	else
>  		alrm->enabled = 0;
> @@ -71,18 +80,18 @@ static int goldfish_rtc_set_alarm(struct device *dev,
> 
>  	if (alrm->enabled) {
>  		rtc_alarm64 = rtc_tm_to_time64(&alrm->time) * NSEC_PER_SEC;
> -		writel((rtc_alarm64 >> 32), base + TIMER_ALARM_HIGH);
> -		writel(rtc_alarm64, base + TIMER_ALARM_LOW);
> -		writel(1, base + TIMER_IRQ_ENABLED);
> +		goldfish_iowrite32((rtc_alarm64 >> 32), base + TIMER_ALARM_HIGH);
> +		goldfish_iowrite32(rtc_alarm64, base + TIMER_ALARM_LOW);
> +		goldfish_iowrite32(1, base + TIMER_IRQ_ENABLED);
>  	} else {
>  		/*
>  		 * if this function was called with enabled=0
>  		 * then it could mean that the application is
>  		 * trying to cancel an ongoing alarm
>  		 */
> -		rtc_status_reg = readl(base + TIMER_ALARM_STATUS);
> +		rtc_status_reg = goldfish_ioread32(base + TIMER_ALARM_STATUS);
>  		if (rtc_status_reg)
> -			writel(1, base + TIMER_CLEAR_ALARM);
> +			goldfish_iowrite32(1, base + TIMER_CLEAR_ALARM);
>  	}
> 
>  	return 0;
> @@ -98,9 +107,9 @@ static int goldfish_rtc_alarm_irq_enable(struct device *dev,
>  	base = rtcdrv->base;
> 
>  	if (enabled)
> -		writel(1, base + TIMER_IRQ_ENABLED);
> +		goldfish_iowrite32(1, base + TIMER_IRQ_ENABLED);
>  	else
> -		writel(0, base + TIMER_IRQ_ENABLED);
> +		goldfish_iowrite32(0, base + TIMER_IRQ_ENABLED);
> 
>  	return 0;
>  }
> @@ -110,7 +119,7 @@ static irqreturn_t goldfish_rtc_interrupt(int irq, 
> void *dev_id)
>  	struct goldfish_rtc *rtcdrv = dev_id;
>  	void __iomem *base = rtcdrv->base;
> 
> -	writel(1, base + TIMER_CLEAR_INTERRUPT);
> +	goldfish_iowrite32(1, base + TIMER_CLEAR_INTERRUPT);
> 
>  	rtc_update_irq(rtcdrv->rtc, 1, RTC_IRQF | RTC_AF);
> 
> @@ -128,8 +137,8 @@ static int goldfish_rtc_read_time(struct device 
> *dev, struct rtc_time *tm)
>  	rtcdrv = dev_get_drvdata(dev);
>  	base = rtcdrv->base;
> 
> -	time_low = readl(base + TIMER_TIME_LOW);
> -	time_high = readl(base + TIMER_TIME_HIGH);
> +	time_low = goldfish_ioread32(base + TIMER_TIME_LOW);
> +	time_high = goldfish_ioread32(base + TIMER_TIME_HIGH);
>  	time = (time_high << 32) | time_low;
> 
>  	do_div(time, NSEC_PER_SEC);
> @@ -149,8 +158,8 @@ static int goldfish_rtc_set_time(struct device 
> *dev, struct rtc_time *tm)
>  	base = rtcdrv->base;
> 
>  	now64 = rtc_tm_to_time64(tm) * NSEC_PER_SEC;
> -	writel((now64 >> 32), base + TIMER_TIME_HIGH);
> -	writel(now64, base + TIMER_TIME_LOW);
> +	goldfish_iowrite32((now64 >> 32), base + TIMER_TIME_HIGH);
> +	goldfish_iowrite32(now64, base + TIMER_TIME_LOW);
> 
>  	return 0;
>  }
> -- 
> 2.34.1

-- 
- Jiaxun

Re: [PATCH v8 3/4] clocksource/drivers: Add a goldfish-timer clocksource

[Arnd Bergmann]

On Sat, Jan 15, 2022 at 8:32 PM Laurent Vivier <laurent@vivier.eu> wrote:

> +
> +/* goldfish endianness depends on CPU endianness */
> +#ifdef CONFIG_CPU_BIG_ENDIAN
> +#define goldfish_ioread32 ioread32be
> +#define goldfish_iowrite32 iowrite32be
> +#else
> +#define goldfish_ioread32 ioread32
> +#define goldfish_iowrite32 iowrite32
> +#endif

This is not what I meant here, as you are breaking big-endian support
for all other
architectures in the process.

On architectures that support both big-endian and little-endian kernels, devices
(including emulated ones) can't know which type of kernel you are running, so
this has to be fixed by architecture. Ideally this macro should be in
an architecture
specific header file, but you can also just make this a check for m68k and  hope
that qemu doesn't duplicate this bug on architectures that gain support for this
driver in the future.

         Arnd

Re: [PATCH v8 3/4] clocksource/drivers: Add a goldfish-timer clocksource

[Laurent Vivier]

Le 16/01/2022 à 11:44, Arnd Bergmann a écrit :
> On Sat, Jan 15, 2022 at 8:32 PM Laurent Vivier <laurent@vivier.eu> wrote:
> 
>> +
>> +/* goldfish endianness depends on CPU endianness */
>> +#ifdef CONFIG_CPU_BIG_ENDIAN
>> +#define goldfish_ioread32 ioread32be
>> +#define goldfish_iowrite32 iowrite32be
>> +#else
>> +#define goldfish_ioread32 ioread32
>> +#define goldfish_iowrite32 iowrite32
>> +#endif
> 
> This is not what I meant here, as you are breaking big-endian support
> for all other
> architectures in the process.
> 
> On architectures that support both big-endian and little-endian kernels, devices
> (including emulated ones) can't know which type of kernel you are running, so
> this has to be fixed by architecture. Ideally this macro should be in
> an architecture
> specific header file, but you can also just make this a check for m68k and  hope
> that qemu doesn't duplicate this bug on architectures that gain support for this
> driver in the future.
> 

Is it OK if I replace "CONFIG_CPU_BIG_ENDIAN" by "CONFIG_M68K" as M68K is the only big-endian 
architecture using goldfish?

Thanks,
Laurent

Re: [PATCH v8 3/4] clocksource/drivers: Add a goldfish-timer clocksource

[Laurent Vivier]

Le 16/01/2022 à 11:44, Arnd Bergmann a écrit :
> On Sat, Jan 15, 2022 at 8:32 PM Laurent Vivier <laurent@vivier.eu> wrote:
> 
>> +
>> +/* goldfish endianness depends on CPU endianness */
>> +#ifdef CONFIG_CPU_BIG_ENDIAN
>> +#define goldfish_ioread32 ioread32be
>> +#define goldfish_iowrite32 iowrite32be
>> +#else
>> +#define goldfish_ioread32 ioread32
>> +#define goldfish_iowrite32 iowrite32
>> +#endif
> 
> This is not what I meant here, as you are breaking big-endian support
> for all other
> architectures in the process.
> 
> On architectures that support both big-endian and little-endian kernels, devices
> (including emulated ones) can't know which type of kernel you are running, so
> this has to be fixed by architecture. Ideally this macro should be in
> an architecture
> specific header file, but you can also just make this a check for m68k and  hope
> that qemu doesn't duplicate this bug on architectures that gain support for this
> driver in the future.

Virtio has exactly the same problem in the past (prio to v1.0), and it uses __LITTLE_ENDIAN in 
virtio_legacy_is_little_endian() to know the endianness of the device.

So the code can become:

#ifdef __LITTLE_ENDIAN
#define goldfish_ioread32 ioread32
#define goldfish_iowrite32 iowrite32
#else
#define goldfish_ioread32 ioread32be
#define goldfish_iowrite32 iowrite32be
#endif

What do you prefer: CONFIG_M68K or __LITTLE_ENDIAN?

Thanks,
Laurent

Re: [PATCH v8 3/4] clocksource/drivers: Add a goldfish-timer clocksource

[Arnd Bergmann]

On Sun, Jan 16, 2022 at 12:54 PM Laurent Vivier <laurent@vivier.eu> wrote:
>
> Virtio has exactly the same problem in the past (prio to v1.0), and it uses __LITTLE_ENDIAN in
> virtio_legacy_is_little_endian() to know the endianness of the device.

Right, that was my point, let's not duplicate the bug from pre-standard virtio.

> So the code can become:
>
> #ifdef __LITTLE_ENDIAN
> #define goldfish_ioread32 ioread32
> #define goldfish_iowrite32 iowrite32
> #else
> #define goldfish_ioread32 ioread32be
> #define goldfish_iowrite32 iowrite32be
> #endif

This is exactly the same as what you had before, it continues to break when
host and guest disagree on the endianess.

> What do you prefer: CONFIG_M68K or __LITTLE_ENDIAN?

Checking for CONFIG_M68K at least has a chance of working, provided
that all existing qemu implementations agree on the semantics here.

       Arnd