soc/intel/denverton_ns: Use `popcnt()` helper

Use the `popcnt()` helper instead of manually counting the number of set
bits in the first `CONFIG_MAX_CPUS` bits with a loop. Also, use unsigned
types to store the number of active/total cores.

Change-Id: Iae6b16991fcf07c9ad67d2b737e490212b8deedd
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/58912
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>

src/soc/intel/denverton_ns/cpu.c

@@ -15,7 +15,7 @@
 #include <device/device.h>
 #include <device/pci.h>
 #include <intelblocks/cpulib.h>
-
+#include <lib.h>
 #include <soc/msr.h>
 #include <soc/cpu.h>
 #include <soc/iomap.h>
@@ -182,28 +182,19 @@ static unsigned int detect_num_cpus_via_cpuid(void)
 	}
 }
 
-static int detect_num_cpus_via_mch(void)
+/* Assumes that FSP has already programmed the cores disabled register */
+static unsigned int detect_num_cpus_via_mch(void)
 {
-	/* Assumes that FSP has already programmed the cores disabled register
-	 */
-	u32 core_exists_mask, active_cores_mask;
-	u32 core_disable_mask;
-	register int active_cores = 0, total_cores = 0;
-	register int counter = 0;
-
 	/* Get Masks for Total Existing SOC Cores and Core Disable Mask */
-	core_exists_mask = MMIO32(DEFAULT_MCHBAR + MCH_BAR_CORE_EXISTS_MASK);
+	const u32 core_exists_mask = MMIO32(DEFAULT_MCHBAR + MCH_BAR_CORE_EXISTS_MASK);
-	core_disable_mask = MMIO32(DEFAULT_MCHBAR + MCH_BAR_CORE_DISABLE_MASK);
+	const u32 core_disable_mask = MMIO32(DEFAULT_MCHBAR + MCH_BAR_CORE_DISABLE_MASK);
-	active_cores_mask = (~core_disable_mask) & core_exists_mask;
+	const u32 active_cores_mask = ~core_disable_mask & core_exists_mask;
 
 	/* Calculate Number of Active Cores */
-	for (; counter < CONFIG_MAX_CPUS;
+	const unsigned int active_cores = popcnt(active_cores_mask);
-	     counter++, active_cores_mask >>= 1, core_exists_mask >>= 1) {
+	const unsigned int total_cores = popcnt(core_exists_mask);
-		active_cores += (active_cores_mask & CORE_BIT_MSK);
-		total_cores += (core_exists_mask & CORE_BIT_MSK);
-	}
 
-	printk(BIOS_DEBUG, "Number of Active Cores: %d of %d total.\n",
+	printk(BIOS_DEBUG, "Number of Active Cores: %u of %u total.\n",
 	       active_cores, total_cores);
 
 	return active_cores;

src/soc/intel/denverton_ns/include/soc/cpu.h

@@ -11,7 +11,6 @@ int get_cpu_count(void);
 #ifndef __ACPI__
 
 #define MSR_CORE_THREAD_COUNT 0x35
-#define CORE_BIT_MSK 0x1
 #define MCH_BAR_CORE_EXISTS_MASK 0x7164
 #define MCH_BAR_CORE_DISABLE_MASK 0x7168