hw/misc: Introduce AMD/Xilix Versal TRNG device

This adds a non-cryptographic grade implementation of the
model for the True Random Number Generator (TRNG) component
in AMD/Xilinx Versal device family.

This implements all 3 modes defined by the actual hardware
specs, all of which selectable by guest software at will
at anytime:
1) PRNG mode, in which the generated sequence is required to
   be reproducible after reseeded by the same 384-bit value
   as supplied by guest software.
2) Test mode, in which the generated sequence is required to
   be reproducible ater reseeded by the same 128-bit test
   seed supplied by guest software.
3) TRNG mode, in which non-reproducible sequence is generated
   based on periodic reseed by a suitable entropy source.

This model is only intended for non-real world testing of
guest software, where cryptographically strong PRNG or TRNG
is not needed.

This model supports versions 1 & 2 of the device, with
default to be version 2; the 'hw-version' uint32 property
can be set to 0x0100 to override the default.

Other implemented properties:
- 'forced-prng', uint64
  When set to non-zero, mode 3's entropy source is implemented
  as a deterministic sequence based on the given value and other
  deterministic parameters.
  This option allows the emulation to test guest software using
  mode 3 and to reproduce data-dependent defects.

- 'fips-fault-events', uint32, bit-mask
  bit 3: Triggers the SP800-90B entropy health test fault irq
  bit 1: Triggers the FIPS 140-2 continuous test fault irq

Signed-off-by: Tong Ho <tong.ho@amd.com>
Message-id: 20231031184611.3029156-2-tong.ho@amd.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

hw/misc/Kconfig

@@ -197,4 +197,7 @@ config DJMEMC
 config IOSB
     bool
 
+config XLNX_VERSAL_TRNG
+    bool
+
 source macio/Kconfig

hw/misc/meson.build

@@ -104,6 +104,9 @@ system_ss.add(when: 'CONFIG_XLNX_VERSAL', if_true: files(
   'xlnx-cfi-if.c',
   'xlnx-versal-cframe-reg.c',
 ))
+system_ss.add(when: 'CONFIG_XLNX_VERSAL_TRNG', if_true: files(
+  'xlnx-versal-trng.c',
+))
 system_ss.add(when: 'CONFIG_STM32F2XX_SYSCFG', if_true: files('stm32f2xx_syscfg.c'))
 system_ss.add(when: 'CONFIG_STM32F4XX_SYSCFG', if_true: files('stm32f4xx_syscfg.c'))
 system_ss.add(when: 'CONFIG_STM32F4XX_EXTI', if_true: files('stm32f4xx_exti.c'))