JSON output mode

README.md

@@ -42,6 +42,12 @@ cd gddr6
 sudo gddr6
 ```
 
+## Running
+```
+sudo gddr6       # for human-readable monitoring
+sudo gddr6 -j    # for one-time JSON output
+```
+
 ## Supported GPUs
 - RTX 4090 (AD102)
 - RTX 4080 Super (AD103)

app/src/app.c

@@ -3,6 +3,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <signal.h>
+#include <string.h>
 
 void register_signal_handlers(void)
 {
@@ -24,12 +25,20 @@ int main(int argc, char **argv)
 
     if (num_devs == 0)
     {
-        printf("No compatible GPU found.\n");
+        fprintf(stderr, "No compatible GPU found.\n");
         return 1;
     }
 
     gddr6_memory_map();
-    gddr6_monitor_temperatures();
+
+    if (argc >= 2 && !strcmp(argv[1], "-j"))
+    {
+        gddr6_print_temperatures_json();
+    }
+    else
+    {
+        gddr6_monitor_temperatures();
+    }
 
     return 0;
 }

lib/include/gddr6.h

@@ -22,12 +22,16 @@ struct gddr6_ctx {
   struct device *devices;
   int num_devices;
   int fd;
+  uint32_t *temperatures;
 };
 
 void gddr6_init(void);
 void gddr6_memory_map(void);
+void gddr6_print_memory_map(void);
 void gddr6_cleanup(int signal);
+void gddr6_get_temperatures(void);
 void gddr6_monitor_temperatures(void);
+void gddr6_print_temperatures_json(void);
 int gddr6_detect_compatible_gpus(void);
 
 #endif // GDDR6_H

lib/src/gddr6.c

@@ -53,7 +53,8 @@ struct device dev_table[] =
 void gddr6_init(void)
 {
     ctx.fd = open("/dev/mem", O_RDONLY);
-    if (ctx.fd == -1) {
+    if (ctx.fd == -1)
+    {
         PRINT_ERROR();
     }
 }
@@ -73,33 +74,38 @@ int gddr6_detect_compatible_gpus(void)
 
     for (pci_dev = pacc->devices; pci_dev != NULL; pci_dev = pci_dev->next) 
     {
-          pci_fill_info(pci_dev, PCI_FILL_IDENT | PCI_FILL_BASES | PCI_FILL_CLASS);
-          for (uint32_t i = 0; i < dev_table_size; ++i) 
-          {
-              if (pci_dev->device_id == dev_table[i].dev_id) 
-              {
-                  struct device *new_devices = realloc(ctx.devices, (ctx.num_devices + 1) * sizeof(struct device));
-                  if (new_devices == NULL)
-                  {
-                      fprintf(stderr, "Memory allocation failed\n");
-                      pci_cleanup(pacc);
-                      free(ctx.devices);
-                      ctx.devices = NULL;
-                      return 0;
-                  }
-                  ctx.devices = new_devices;
-
-                  ctx.devices[ctx.num_devices] = dev_table[i];
-                  ctx.devices[ctx.num_devices].bar0 = (pci_dev->base_addr[0] & 0xffffffff);
-                  ctx.devices[ctx.num_devices].bus = pci_dev->bus;
-                  ctx.devices[ctx.num_devices].dev = pci_dev->dev;
-                  ctx.devices[ctx.num_devices].func = pci_dev->func;
-                  ctx.num_devices++;
-              }
-          }
-      }
+        pci_fill_info(pci_dev, PCI_FILL_IDENT | PCI_FILL_BASES | PCI_FILL_CLASS);
+        for (uint32_t i = 0; i < dev_table_size; ++i) 
+        {
+            if (pci_dev->device_id == dev_table[i].dev_id) 
+            {
+                struct device *new_devices = realloc(ctx.devices, (ctx.num_devices + 1) * sizeof(struct device));
+                if (new_devices == NULL)
+                {
+                    fprintf(stderr, "Memory allocation failed\n");
+                    exit(EXIT_FAILURE);
+                }
+                ctx.devices = new_devices;
+
+                ctx.devices[ctx.num_devices] = dev_table[i];
+                ctx.devices[ctx.num_devices].bar0 = (pci_dev->base_addr[0] & 0xffffffff);
+                ctx.devices[ctx.num_devices].bus = pci_dev->bus;
+                ctx.devices[ctx.num_devices].dev = pci_dev->dev;
+                ctx.devices[ctx.num_devices].func = pci_dev->func;
+                ctx.num_devices++;
+            }
+        }
+    }
 
     pci_cleanup(pacc);
+
+    ctx.temperatures = malloc(ctx.num_devices * sizeof(uint32_t));
+    if (ctx.temperatures == NULL)
+    {
+        fprintf(stderr, "Memory allocation failed\n");
+        exit(EXIT_FAILURE);
+    }
+
     return ctx.num_devices;
 }
 
@@ -114,36 +120,82 @@ void gddr6_memory_map(void)
         if (ctx.devices[i].mapped_addr == MAP_FAILED)
         {
             ctx.devices[i].mapped_addr = NULL;
-            fprintf(stderr, "Memory mapping failed for pci=%x:%x:%x\n", ctx.devices[i].bus, ctx.devices[i].dev, ctx.devices[i].func);
+            fprintf(stderr, "Memory mapping failed for pci=%02X:%02X.%X\n", ctx.devices[i].bus, ctx.devices[i].dev, ctx.devices[i].func);
             fprintf(stderr, "Did you enable iomem=relaxed? Are you r00t?\n");
             exit(EXIT_FAILURE);
-        } else {
-            printf("Device: %s %s (%s / 0x%04x) pci=%x:%x:%x\n", ctx.devices[i].name, ctx.devices[i].vram,
-            ctx.devices[i].arch, ctx.devices[i].dev_id, ctx.devices[i].bus, ctx.devices[i].dev, ctx.devices[i].func);
         }
     }
 }
 
-void gddr6_monitor_temperatures(void)
+void gddr6_print_memory_map(void)
 {
-   while (1) {
-        printf("\rVRAM Temps: |");
-        for (uint32_t i = 0; i < ctx.num_devices; i++)
-        {
-            if (ctx.devices[i].mapped_addr == NULL || ctx.devices[i].mapped_addr == MAP_FAILED)
-            {
-                continue;
-            }
+    for (uint32_t i = 0; i < ctx.num_devices; i++)
+    {
+        if (ctx.devices[i].mapped_addr == NULL || ctx.devices[i].mapped_addr == MAP_FAILED) {
+            continue;
+        }
 
+        printf("Device: %s %s (%s / 0x%04x) pci=%02X:%02X.%X\n", ctx.devices[i].name, ctx.devices[i].vram,
+            ctx.devices[i].arch, ctx.devices[i].dev_id, ctx.devices[i].bus, ctx.devices[i].dev, ctx.devices[i].func);
+    }
+}
+
+void gddr6_get_temperatures(void)
+{
+    for (uint32_t i = 0; i < ctx.num_devices; i++)
+    {
+        if (ctx.devices[i].mapped_addr == NULL || ctx.devices[i].mapped_addr == MAP_FAILED)
+        {
+            ctx.temperatures[i] = 0;
+        }
+        else
+        {
             void *virt_addr = (uint8_t *) ctx.devices[i].mapped_addr + (ctx.devices[i].phys_addr  - ctx.devices[i].base_offset);
             uint32_t read_result = *((uint32_t *)virt_addr);
             uint32_t temp = ((read_result & 0x00000fff) / 0x20);
+            ctx.temperatures[i] = temp;
+        }
+    }
+}
 
-            printf(" %3u°C |", temp);
+void gddr6_monitor_temperatures(void)
+{
+    gddr6_print_memory_map();
+
+    while (1)
+    {
+        gddr6_get_temperatures();
+        printf("\rVRAM Temps: |");
+        for (uint32_t i = 0; i < ctx.num_devices; i++)
+        {
+            printf(" %3u°C |", ctx.temperatures[i]);
         }
         fflush(stdout);
         sleep(1);
-   }
+    }
+}
+
+void gddr6_print_temperatures_json(void)
+{
+    if (ctx.num_devices == 0)
+    {
+        printf("[]\n");
+        return;
+    }
+
+    gddr6_get_temperatures();
+
+    printf("[\n");
+    for (uint32_t i = 0; i < ctx.num_devices; i++)
+    {
+        char *delimiter = i < ctx.num_devices - 1 ? "," : "";
+        printf(
+            "  {\"name\": \"%s\", \"vram\": \"%s\", \"arch\": \"%s\", \"dev_id\": \"0x%04x\", \"pci_id\": \"%02X:%02X.%X\", \"temp\": %d}%s\n",
+            ctx.devices[i].name, ctx.devices[i].vram, ctx.devices[i].arch, ctx.devices[i].dev_id, ctx.devices[i].bus, ctx.devices[i].dev,
+            ctx.devices[i].func, ctx.temperatures[i], delimiter
+        );
+    }
+    printf("]\n");
 }
 
 void gddr6_cleanup(int signal)