[v1.06][ARM] Implement automatic SoC inferring from device tree

This is a major change in the SoC detection methodology.

Previous to this commit, the SoC (model, vendor and manufacturing
process) would only appear if the exact model was found in the LUT.
In other words, every supported SoC must be added manually to the LUT.
This would allow to show the precise SoC model and the manufacturing
process, which can only be hardcoded (i.e., it cannot be dynamically
determined).

This commit introduces guess_raw_soc_from_devtree, a new way of
inferring the SoC. This simply reads from the compatible file in the
device tree and tries to find a matching vendor to that string. If
there is a match, then we simply copy the model also from the
compatible string and show it directly.

This new implementation will show a less "precise" SoC name and
no manufacturing process because there would be no hardcoded value for
that SoC. However, it improves the scalability of the SoC detection
significantly because there is no longer a need to hardcode every
single SoC.

Lastly, there are some SoC vendors intentionally left outside the
scope of this function: For now I prefer to keep updating manually
the LUT for those to ensure the highest quality detection (e.g.,
showing precise SoC name and manufacturing process).

src/arm/soc.c

@@ -1044,6 +1044,64 @@ struct system_on_chip* guess_soc_from_devtree(struct system_on_chip* soc) {
   DT_END(dt, len)
 }
 
+// This function is different from the rest guess_soc_from_xxx, which try infering
+// the exact SoC model by matching some string against a list of known values.
+// On the other hand, this function will just try to infer the SoC vendor first by
+// matching the device tree vendor name (i.e., the first value, before the comma).
+// If that is successfull, then it also fills in the SoC name using the string from
+// the device tree.
+// The critical difference is that this function does not need a LUT to fill in the
+// SoC, it just needs to find a known vendor. On the other hand, the detection is
+// less powerful since we cannot get the manufacturing process, and the SoC name will
+// come directly from the device tree, meaning that it will likely be less precise.
+struct system_on_chip* guess_raw_soc_from_devtree(struct system_on_chip* soc) {
+  int num_vendors;
+  struct devtree** dt_vendors = get_devtree_compatible_struct(&num_vendors);
+  if (dt_vendors == NULL) {
+    return soc;
+  }
+
+  typedef struct {
+    char* compatible;
+    VENDOR soc_vendor;
+  } devtreeToVendor;
+
+  // https://elixir.bootlin.com/linux/v6.10.6/source/arch/arm64/boot/dts
+  // grep -oR --color -E 'compatible = ".*"' <soc_vendor> | cut -d '=' -f2 | cut -d ',' -f1 | tr -d '"' | sort | uniq -c | sort
+  // - The following vendors are not included because they dont seem to be present in dts:
+  // SOC_VENDOR_(KIRIN, KUNPENG, GOOGLE, AMPERE).
+  // - The commented vendors are not included intentionally, because I prefer updating its LUT manually.
+  devtreeToVendor socFromDevtree[] = {
+    // {"qcom",       SOC_VENDOR_SNAPDRAGON},
+    // {"samsung",    SOC_VENDOR_EXYNOS},
+    // {"brcm",       SOC_VENDOR_BROADCOM},
+    // {"apple",      SOC_VENDOR_APPLE},
+    // {"rockchip",   SOC_VENDOR_ROCKCHIP},
+    // {"nvidia",     SOC_VENDOR_NVIDIA},
+    {"mediatek",   SOC_VENDOR_MEDIATEK},
+    {"fsl",        SOC_VENDOR_NXP     },
+    {"nxp",        SOC_VENDOR_NXP     },
+    {"amlogic",    SOC_VENDOR_AMLOGIC },
+    {"marvell",    SOC_VENDOR_MARVELL },
+    {NULL,         SOC_VENDOR_UNKNOWN }
+  };
+
+  int index = 0;
+  while (socFromDevtree[index].compatible != 0x0) {
+    for (int i=0; i < num_vendors; i++) {
+      if (strcmp(socFromDevtree[index].compatible, dt_vendors[i]->vendor) == 0) {
+        fill_soc_raw(soc, dt_vendors[i]->model, socFromDevtree[index].soc_vendor);
+        printWarn("Your SoC is unsupported by cpufetch but could still be detected successfully. If you want to help improve the project, please paste the output of 'cpufetch --verbose' on https://github.com/Dr-Noob/cpufetch/issues");
+        return soc;
+      }
+    }
+    index++;
+  }
+
+  printWarn("guess_raw_soc_from_devtree: No device matched the list");
+  return soc;
+}
+
 struct system_on_chip* guess_soc_from_pci(struct system_on_chip* soc, struct cpuInfo* cpu) {
   struct pci_devices * pci = get_pci_devices();
   if (pci == NULL) {
@@ -1270,6 +1328,11 @@ struct system_on_chip* get_soc(struct cpuInfo* cpu) {
     if(soc->vendor == SOC_VENDOR_UNKNOWN) {
       soc = guess_soc_from_pci(soc, cpu);
     }
+    if (soc->vendor == SOC_VENDOR_UNKNOWN) {
+      // If we fall here it means all previous functions failed to detect the SoC.
+      // In such case, try with our last resort. If it also fails, we will just give up
+      soc = guess_raw_soc_from_devtree(soc);
+    }
   }
 #elif defined __APPLE__ || __MACH__
   soc = guess_soc_apple(soc);
@@ -1295,16 +1358,13 @@ struct system_on_chip* get_soc(struct cpuInfo* cpu) {
   soc->vendor = try_match_soc_vendor_name(processor_name_string);
   soc->model = SOC_MODEL_UNKNOWN;
   soc->process = UNKNOWN;
-
 #else
-
-  if(soc->model == SOC_MODEL_UNKNOWN) {
-    // raw_name might not be NULL, but if we were unable to find
-    // the exact SoC, just print "Unkwnown"
+  if(soc->raw_name == NULL) {
+    // We were unable to find the SoC, so just initialize raw_name
+    // with the unknown string
     soc->raw_name = emalloc(sizeof(char) * (strlen(STRING_UNKNOWN)+1));
     snprintf(soc->raw_name, strlen(STRING_UNKNOWN)+1, STRING_UNKNOWN);
   }
-
 #endif 
 
   return soc;