hw/misc: Add a PWM module for NPCM7XX

The PWM module is part of NPCM7XX module. Each NPCM7XX module has two
identical PWM modules. Each module contains 4 PWM entries. Each PWM has
two outputs: frequency and duty_cycle. Both are computed using inputs
from software side.

This module does not model detail pulse signals since it is expensive.
It also does not model interrupts and watchdogs that are dependant on
the detail models. The interfaces for these are left in the module so
that anyone in need for these functionalities can implement on their
own.

The user can read the duty cycle and frequency using qom-get command.

Reviewed-by: Havard Skinnemoen <[email protected]>
Reviewed-by: Tyrone Ting <[email protected]>
Signed-off-by: Hao Wu <[email protected]>
Message-id: [email protected]
Reviewed-by: Peter Maydell <[email protected]>
Signed-off-by: Peter Maydell <[email protected]>

docs/system/arm/nuvoton.rst

@@ -42,6 +42,7 @@ Supported devices
  * USB host (USBH)
  * GPIO controller
  * Analog to Digital Converter (ADC)
+ * Pulse Width Modulation (PWM)
 
 Missing devices
 ---------------
@@ -61,7 +62,6 @@ Missing devices
  * Peripheral SPI controller (PSPI)
  * SD/MMC host
  * PECI interface
- * Pulse Width Modulation (PWM)
  * Tachometer
  * PCI and PCIe root complex and bridges
  * VDM and MCTP support

hw/arm/npcm7xx.c

@@ -102,6 +102,8 @@ enum NPCM7xxInterrupt {
     NPCM7XX_WDG2_IRQ,                   /* Timer Module 2 Watchdog */
     NPCM7XX_EHCI_IRQ            = 61,
     NPCM7XX_OHCI_IRQ            = 62,
+    NPCM7XX_PWM0_IRQ            = 93,   /* PWM module 0 */
+    NPCM7XX_PWM1_IRQ,                   /* PWM module 1 */
     NPCM7XX_GPIO0_IRQ           = 116,
     NPCM7XX_GPIO1_IRQ,
     NPCM7XX_GPIO2_IRQ,
@@ -144,6 +146,12 @@ static const hwaddr npcm7xx_fiu3_flash_addr[] = {
     0xb8000000, /* CS3 */
 };
 
+/* Register base address for each PWM Module */
+static const hwaddr npcm7xx_pwm_addr[] = {
+    0xf0103000,
+    0xf0104000,
+};
+
 static const struct {
     hwaddr regs_addr;
     uint32_t unconnected_pins;
@@ -353,6 +361,10 @@ static void npcm7xx_init(Object *obj)
         object_initialize_child(obj, npcm7xx_fiu[i].name, &s->fiu[i],
                                 TYPE_NPCM7XX_FIU);
     }
+
+    for (i = 0; i < ARRAY_SIZE(s->pwm); i++) {
+        object_initialize_child(obj, "pwm[*]", &s->pwm[i], TYPE_NPCM7XX_PWM);
+    }
 }
 
 static void npcm7xx_realize(DeviceState *dev, Error **errp)
@@ -513,6 +525,18 @@ static void npcm7xx_realize(DeviceState *dev, Error **errp)
     sysbus_connect_irq(SYS_BUS_DEVICE(&s->ohci), 0,
                        npcm7xx_irq(s, NPCM7XX_OHCI_IRQ));
 
+    /* PWM Modules. Cannot fail. */
+    QEMU_BUILD_BUG_ON(ARRAY_SIZE(npcm7xx_pwm_addr) != ARRAY_SIZE(s->pwm));
+    for (i = 0; i < ARRAY_SIZE(s->pwm); i++) {
+        SysBusDevice *sbd = SYS_BUS_DEVICE(&s->pwm[i]);
+
+        qdev_connect_clock_in(DEVICE(&s->pwm[i]), "clock", qdev_get_clock_out(
+                    DEVICE(&s->clk), "apb3-clock"));
+        sysbus_realize(sbd, &error_abort);
+        sysbus_mmio_map(sbd, 0, npcm7xx_pwm_addr[i]);
+        sysbus_connect_irq(sbd, i, npcm7xx_irq(s, NPCM7XX_PWM0_IRQ + i));
+    }
+
     /*
      * Flash Interface Unit (FIU). Can fail if incorrect number of chip selects
      * specified, but this is a programming error.
@@ -580,8 +604,6 @@ static void npcm7xx_realize(DeviceState *dev, Error **errp)
     create_unimplemented_device("npcm7xx.peci",         0xf0100000,   4 * KiB);
     create_unimplemented_device("npcm7xx.siox[1]",      0xf0101000,   4 * KiB);
     create_unimplemented_device("npcm7xx.siox[2]",      0xf0102000,   4 * KiB);
-    create_unimplemented_device("npcm7xx.pwm[0]",       0xf0103000,   4 * KiB);
-    create_unimplemented_device("npcm7xx.pwm[1]",       0xf0104000,   4 * KiB);
     create_unimplemented_device("npcm7xx.mft[0]",       0xf0180000,   4 * KiB);
     create_unimplemented_device("npcm7xx.mft[1]",       0xf0181000,   4 * KiB);
     create_unimplemented_device("npcm7xx.mft[2]",       0xf0182000,   4 * KiB);

hw/misc/meson.build

@@ -64,6 +64,7 @@ softmmu_ss.add(when: 'CONFIG_MAINSTONE', if_true: files('mst_fpga.c'))
 softmmu_ss.add(when: 'CONFIG_NPCM7XX', if_true: files(
   'npcm7xx_clk.c',
   'npcm7xx_gcr.c',
+  'npcm7xx_pwm.c',
   'npcm7xx_rng.c',
 ))
 softmmu_ss.add(when: 'CONFIG_OMAP', if_true: files(