Create wr-pci-leds example

docs/specs/wr-pci-leds.rst

@@ -0,0 +1,125 @@
+=================
+Wind River PCI LEDs example device
+=================
+-------------------------
+Sharing how to create a barebone QEMU custom device
+-------------------------
+
+Standalone run
+============
+Run
+  ::
+
+    ./qemu-system-x86_64 -device wr-pci-leds
+    >>      <QEMU> Hello this is my-device PCI device
+
+Linux run
+============
+Integrate the example device driver into Kernel image, and during the boot
+  ::
+
+    >>      <DRIVER> Hello, this is your leds QEMU driver
+    >>      <DRIVER> Found device vid: 0xABCD pid: 0x525
+
+On command shell,
+  ::
+
+    # echo 11 > /sys/class/leds/qemu:led0/brightness 
+    >>      <QEMU> Write to 0 with 11 4
+    >>      <QEMU> Read from 0 for 4
+    >>      <DRIVER> leds_qemu regs is 11
+
+Linux, drivers/leds/leds-qemu.c
+============
+.. code:: C
+  :linenos:
+
+  #include <linux/module.h>
+  #include <linux/pci.h>
+  #include <linux/leds.h>
+
+  #define DRV_NAME "leds_qemu"
+  #define PCI_VENDOR_ID_QEMU 0xabcd
+  #define PCI_DEVICE_ID_QEMU 0x0525
+
+  static const struct pci_device_id pci_table[] = {
+          { PCI_DEVICE(PCI_VENDOR_ID_QEMU, PCI_DEVICE_ID_QEMU), },
+          { 0, },
+  };
+  MODULE_DEVICE_TABLE(pci, pci_table);
+
+  struct leds_qemu_priv {
+          uint32_t* regs;
+  	struct led_classdev led0_qemu_cdev;
+  };
+
+  static int leds_qemu_set(struct led_classdev *led_cdev, enum led_brightness value)
+  {
+  	struct leds_qemu_priv* s= container_of(led_cdev, struct leds_qemu_priv, led0_qemu_cdev);
+  	writel((u8)value, s->regs);
+  	int v = readl(s->regs);
+  	printk(KERN_INFO ">>\t<DRIVER> leds_qemu regs is %d\n",v);
+  	return 0;
+  }
+
+  static int leds_qemu_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
+  {
+          int rc = 0;
+          printk(KERN_INFO ">>\t<DRIVER> Hello, this is your leds QEMU driver\n");
+
+          struct leds_qemu_priv* priv = devm_kzalloc(&pdev->dev,sizeof(struct leds_qemu_priv), GFP_KERNEL);
+          pci_set_drvdata(pdev, priv);
+
+          uint16_t vendor, device;
+          pci_read_config_word(pdev, PCI_VENDOR_ID, &vendor);
+          pci_read_config_word(pdev, PCI_DEVICE_ID, &device);
+          printk(KERN_INFO ">>\t<DRIVER> Found device vid: 0x%X pid: 0x%X\n", vendor, device);
+
+          rc = pci_enable_device(pdev);
+          if (rc) return rc;
+          rc = pci_request_regions(pdev,DRV_NAME);
+          if (rc) {
+          	pci_disable_device(pdev);
+  		return rc;
+  	}
+
+          resource_size_t pciaddr = pci_resource_start(pdev,0);
+          uint32_t* regs = ioremap(pciaddr,32);
+          priv->regs = regs;
+          priv->led0_qemu_cdev.name="qemu:led0";
+          priv->led0_qemu_cdev.max_brightness=255;
+          priv->led0_qemu_cdev.brightness_set_blocking=leds_qemu_set;
+          rc = led_classdev_register(&pdev->dev, &priv->led0_qemu_cdev);
+
+          return 0;
+  }
+  static void leds_qemu_remove (struct pci_dev *pdev)
+  {
+  }
+
+  static struct pci_driver leds_qemu_driver = {
+          .name = DRV_NAME,
+          .id_table = pci_table,
+          .probe = leds_qemu_probe,
+          .remove = leds_qemu_remove,
+  };
+
+  module_pci_driver(leds_qemu_driver);
+  MODULE_LICENSE("GPL");
+
+
+Linux, drivers/leds/KConfig
+=================
+.. code::
+
+  config LEDS_QEMU
+        tristate "LED support for my-device in QEMU"
+        depends on LEDS_CLASS
+        depends on PCI
+
+
+Linux, drivers/leds/Makefile
+=================
+.. code::
+
+    obj-$(CONFIG_LEDS_QEMU)                 += leds-qemu.o

hw/misc/Kconfig

@@ -213,4 +213,9 @@ config IOSB
 config XLNX_VERSAL_TRNG
     bool
 
+config WR_PCI_LEDS
+    bool
+    default y if PCI_DEVICES
+    depends on PCI
+
 source macio/Kconfig

hw/misc/meson.build

@@ -157,3 +157,6 @@ system_ss.add(when: 'CONFIG_SBSA_REF', if_true: files('sbsa_ec.c'))
 
 # HPPA devices
 system_ss.add(when: 'CONFIG_LASI', if_true: files('lasi.c'))
+
+# WR PCI LEDs example device
+system_ss.add(when: 'CONFIG_WR_PCI_LEDS', if_true: files('wr-pci-leds.c'))

hw/misc/wr-pci-leds.c

@@ -0,0 +1,80 @@
+#include "qemu/osdep.h"
+#include "hw/pci/pci_device.h"
+
+#define TYPE_MY_DEVICE "wr-pci-leds"
+OBJECT_DECLARE_SIMPLE_TYPE(MyDeviceState, MY_DEVICE)
+
+typedef struct MyDeviceState
+{
+    PCIDevice parent_obj;
+    MemoryRegion bar;
+
+    int32_t led0,led1;
+} MyDeviceState;
+static void my_device_write(void *opaque, hwaddr addr, uint64_t data, unsigned size)
+{
+    printf(">>\t<QEMU> Write to %lu with %lu %u\n",addr, data, size);
+    MyDeviceState* s = opaque;
+    switch (addr) {
+        case 0: s->led0=data; break;
+        case 4: s->led1=data; break;
+        default: return;
+    }
+}
+static uint64_t my_device_read(void *opaque, hwaddr addr, unsigned size)
+{
+    printf(">>\t<QEMU> Read from %lu for %u\n",addr, size);
+    MyDeviceState* s = opaque;
+    switch (addr) {
+        case 0: return s->led0;
+        case 4: return s->led1;
+        default: return ~0;
+    }
+}
+static const MemoryRegionOps my_device_ops = {
+        .write = my_device_write,
+        .read = my_device_read,
+};
+static void pci_my_device_realize(PCIDevice *dev, Error **errp)
+{
+    printf(">>\t<QEMU> Hello this is my-device PCI device\n");
+    MyDeviceState *s = MY_DEVICE(dev);
+    memory_region_init_io(&s->bar, OBJECT(s), &my_device_ops, s, "my-device", 32);
+    pci_register_bar(dev, 0 , PCI_BASE_ADDRESS_SPACE_MEMORY, &s->bar);
+
+}
+static void my_device_class_init(ObjectClass *klass, void *data)
+{
+    PCIDeviceClass *k = PCI_DEVICE_CLASS(klass);
+
+    k->vendor_id = 0xabcd;
+    k->device_id = 0x0525;
+    k->realize = pci_my_device_realize;
+    k->class_id = PCI_CLASS_OTHERS;
+}
+static const TypeInfo my_device_info = {
+    .name = TYPE_MY_DEVICE,
+    .parent = TYPE_PCI_DEVICE,
+    .instance_size = sizeof(MyDeviceState),
+    .class_init = my_device_class_init,
+    .interfaces = (InterfaceInfo[]) {
+            { INTERFACE_CONVENTIONAL_PCI_DEVICE },
+            { },
+    },
+};
+static void my_device_register_types(void)
+{
+    type_register_static(&my_device_info);
+}
+type_init(my_device_register_types)
+
+/* Notes:
+ *
+   // Kconfig
+  config MY_DEVICE
+    bool
+    default y
+
+    // mesa.build
+    system_ss.add(when: 'CONFIG_MY_DEVICE', if_true: files('my-device.c'))
+*/