hw/i2c/allwinner-i2c: Fix subclassing of TYPE_AW_I2C_SUN6I

In commit 8461bfdca9c we added the TYPE_AW_I2C_SUN6I, which is a
minor variant of the TYPE_AW_I2C device. However, we didn't quite
get the

hw/i2c/allwinner-i2c: Fix subclassing of TYPE_AW_I2C_SUN6I

In commit 8461bfdca9c we added the TYPE_AW_I2C_SUN6I, which is a
minor variant of the TYPE_AW_I2C device. However, we didn't quite
get the class hierarchy right. We made the new TYPE_AW_I2C_SUN6I a
subclass of TYPE_SYS_BUS_DEVICE, which means that you can't validly
use a pointer to this object via the AW_I2C() cast macro, which
insists on having something that is an instance of TYPE_AW_I2C or
some subclass of that type.

This only causes a problem if QOM cast macro debugging is enabled;
that is supposed to be on by default, but a mistake in the meson
conversion in commit c55cf6ab03f4c meant that it ended up disabled by
default, and we didn't catch this bug.

Fix the problem by arranging the classes in the same way we do for
TYPE_PL011 and TYPE_PL011_LUMINARY in hw/char/pl011.c -- make the
variant class be a subclass of the "normal" version of the device.

This was reported in
https://gitlab.com/qemu-project/qemu/-/issues/1586 but this fix alone
isn't sufficient, as there is a separate cast-related issue in the
CXL code in pci_expander_bridge.c.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Corey Minyard <cminyard@mvista.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>

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hw: allwinner-i2c: Fix TWI_CNTR_INT_FLAG on SUN6i SoCs

TWI_CNTR_INT_FLAG is W1C(write 1 to clear and write 0 has non-effect)
register on SUN6i based SoCs, we should lower interrupt when the guest
se

hw: allwinner-i2c: Fix TWI_CNTR_INT_FLAG on SUN6i SoCs

TWI_CNTR_INT_FLAG is W1C(write 1 to clear and write 0 has non-effect)
register on SUN6i based SoCs, we should lower interrupt when the guest
set this bit.

The linux kernel will hang in irq handler(mv64xxx_i2c_intr) if no
device connected on the i2c bus, next is the trace log:

allwinner_i2c_write write CNTR(0x0c): 0xc4 A_ACK BUS_EN INT_EN
allwinner_i2c_write write CNTR(0x0c): 0xcc A_ACK INT_FLAG BUS_EN INT_EN
allwinner_i2c_read read CNTR(0x0c): 0xcc A_ACK INT_FLAG BUS_EN INT_EN
allwinner_i2c_read read STAT(0x10): 0x20 STAT_M_ADDR_WR_NACK
allwinner_i2c_write write CNTR(0x0c): 0x54 A_ACK M_STP BUS_EN
allwinner_i2c_write write CNTR(0x0c): 0x4c A_ACK INT_FLAG BUS_EN
allwinner_i2c_read read CNTR(0x0c): 0x4c A_ACK INT_FLAG BUS_EN
allwinner_i2c_read read STAT(0x10): 0xf8 STAT_IDLE
allwinner_i2c_write write CNTR(0x0c): 0x54 A_ACK M_STP BUS_EN
allwinner_i2c_write write CNTR(0x0c): 0x4c A_ACK INT_FLAG BUS_EN
allwinner_i2c_read read CNTR(0x0c): 0x4c A_ACK INT_FLAG BUS_EN
allwinner_i2c_read read STAT(0x10): 0xf8 STAT_IDLE
...

Fix it.

Signed-off-by: qianfan Zhao <qianfanguijin@163.com>
Reviewed-by: Strahinja Jankovic <strahinja.p.jankovic@gmail.com>
Tested-by: Strahinja Jankovic <strahinja.p.jankovic@gmail.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

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{hw/i2c,docs/system/arm}: Allwinner TWI/I2C Emulation

This patch implements Allwinner TWI/I2C controller emulation. Only
master-mode functionality is implemented.

The SPL boot for Cubieboard expect

{hw/i2c,docs/system/arm}: Allwinner TWI/I2C Emulation

This patch implements Allwinner TWI/I2C controller emulation. Only
master-mode functionality is implemented.

The SPL boot for Cubieboard expects AXP209 PMIC on TWI0/I2C0 bus, so this is
first part enabling the TWI/I2C bus operation.

Since both Allwinner A10 and H3 use the same module, it is added for
both boards.

Docs are also updated for Cubieboard and Orangepi-PC board to indicate
I2C availability.

Signed-off-by: Strahinja Jankovic <strahinja.p.jankovic@gmail.com>
Reviewed-by: Niek Linnenbank <nieklinnenbank@gmail.com>
Message-id: 20221226220303.14420-4-strahinja.p.jankovic@gmail.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

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