Fixed MTP to work with TWRP

arch/arm64/kernel/cpu_errata.c

@@ -0,0 +1,120 @@
+/*
+ * Contains CPU specific errata definitions
+ *
+ * Copyright (C) 2014 ARM Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#define pr_fmt(fmt) "alternative: " fmt
+
+#include <linux/types.h>
+#include <asm/cpu.h>
+#include <asm/cputype.h>
+#include <asm/cpufeature.h>
+
+#define MIDR_CORTEX_A53 MIDR_CPU_PART(ARM_CPU_IMP_ARM, ARM_CPU_PART_CORTEX_A53)
+#define MIDR_CORTEX_A57 MIDR_CPU_PART(ARM_CPU_IMP_ARM, ARM_CPU_PART_CORTEX_A57)
+
+/*
+ * Add a struct or another datatype to the union below if you need
+ * different means to detect an affected CPU.
+ */
+struct arm64_cpu_capabilities {
+	const char *desc;
+	u16 capability;
+	bool (*is_affected)(struct arm64_cpu_capabilities *);
+	union {
+		struct {
+			u32 midr_model;
+			u32 midr_range_min, midr_range_max;
+		};
+	};
+};
+
+#define CPU_MODEL_MASK (MIDR_IMPLEMENTOR_MASK | MIDR_PARTNUM_MASK | \
+			MIDR_ARCHITECTURE_MASK)
+
+static bool __maybe_unused
+is_affected_midr_range(struct arm64_cpu_capabilities *entry)
+{
+	u32 midr = read_cpuid_id();
+
+	if ((midr & CPU_MODEL_MASK) != entry->midr_model)
+		return false;
+
+	midr &= MIDR_REVISION_MASK | MIDR_VARIANT_MASK;
+
+	return (midr >= entry->midr_range_min && midr <= entry->midr_range_max);
+}
+
+#define MIDR_RANGE(model, min, max) \
+	.is_affected = is_affected_midr_range, \
+	.midr_model = model, \
+	.midr_range_min = min, \
+	.midr_range_max = max
+
+struct arm64_cpu_capabilities arm64_errata[] = {
+#if	defined(CONFIG_ARM64_ERRATUM_826319) || \
+	defined(CONFIG_ARM64_ERRATUM_827319) || \
+	defined(CONFIG_ARM64_ERRATUM_824069)
+	{
+	/* Cortex-A53 r0p[012] */
+		.desc = "ARM errata 826319, 827319, 824069",
+		.capability = ARM64_WORKAROUND_CLEAN_CACHE,
+		MIDR_RANGE(MIDR_CORTEX_A53, 0x00, 0x02),
+	},
+#endif
+#ifdef CONFIG_ARM64_ERRATUM_819472
+	{
+	/* Cortex-A53 r0p[01] */
+		.desc = "ARM errata 819472",
+		.capability = ARM64_WORKAROUND_CLEAN_CACHE,
+		MIDR_RANGE(MIDR_CORTEX_A53, 0x00, 0x01),
+	},
+#endif
+#ifdef CONFIG_ARM64_ERRATUM_832075
+	{
+	/* Cortex-A57 r0p0 - r1p2 */
+		.desc = "ARM erratum 832075",
+		.capability = ARM64_WORKAROUND_DEVICE_LOAD_ACQUIRE,
+		MIDR_RANGE(MIDR_CORTEX_A57, 0x00,
+			   (1 << MIDR_VARIANT_SHIFT) | 2),
+	},
+#endif
+#ifdef CONFIG_ARM64_ERRATUM_845719
+	{
+	/* Cortex-A53 r0p[01234] */
+		.desc = "ARM erratum 845719",
+		.capability = ARM64_WORKAROUND_845719,
+		MIDR_RANGE(MIDR_CORTEX_A53, 0x00, 0x04),
+	},
+#endif
+	{
+	}
+};
+
+void check_local_cpu_errata(void)
+{
+	struct arm64_cpu_capabilities *cpus = arm64_errata;
+	int i;
+
+	for (i = 0; cpus[i].desc; i++) {
+		if (!cpus[i].is_affected(&cpus[i]))
+			continue;
+
+		if (!cpus_have_cap(cpus[i].capability))
+			pr_info("enabling workaround for %s\n", cpus[i].desc);
+		cpus_set_cap(cpus[i].capability);
+	}
+}