arm64: FFH: Move ACPI specific code into drivers/acpi/arm64/

The ACPI FFH Opregion code can be moved out of arm64 arch code as
it just uses SMCCC. Move all the ACPI FFH Opregion code into
drivers/acpi/arm64/ffh.c

Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Hanjun Guo <guohanjun@huawei.com>
Link: https://lore.kernel.org/r/20240605131458.3341095-4-sudeep.holla@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

2 files changed, 108 insertions, 0 deletions

diff --git a/drivers/acpi/arm64/Makefile b/drivers/acpi/arm64/Makefile
index 2efee23f00b4..05ecde9eaabe 100644
--- a/drivers/acpi/arm64/Makefile
+++ b/drivers/acpi/arm64/Makefile
@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0-only
 obj-$(CONFIG_ACPI_AGDI) 	+= agdi.o
 obj-$(CONFIG_ACPI_APMT) 	+= apmt.o
+obj-$(CONFIG_ACPI_FFH)		+= ffh.o
 obj-$(CONFIG_ACPI_GTDT) 	+= gtdt.o
 obj-$(CONFIG_ACPI_IORT) 	+= iort.o
 obj-$(CONFIG_ACPI_PROCESSOR_IDLE) += cpuidle.o
diff --git a/drivers/acpi/arm64/ffh.c b/drivers/acpi/arm64/ffh.c
new file mode 100644
index 000000000000..877edc6557e9
--- /dev/null
+++ b/drivers/acpi/arm64/ffh.c
@@ -0,0 +1,107 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/acpi.h>
+#include <linux/arm-smccc.h>
+#include <linux/slab.h>
+
+/*
+ * Implements ARM64 specific callbacks to support ACPI FFH Operation Region as
+ * specified in https://developer.arm.com/docs/den0048/latest
+ */
+struct acpi_ffh_data {
+	struct acpi_ffh_info info;
+	void (*invoke_ffh_fn)(unsigned long a0, unsigned long a1,
+			      unsigned long a2, unsigned long a3,
+			      unsigned long a4, unsigned long a5,
+			      unsigned long a6, unsigned long a7,
+			      struct arm_smccc_res *args,
+			      struct arm_smccc_quirk *res);
+	void (*invoke_ffh64_fn)(const struct arm_smccc_1_2_regs *args,
+				struct arm_smccc_1_2_regs *res);
+};
+
+int acpi_ffh_address_space_arch_setup(void *handler_ctxt, void **region_ctxt)
+{
+	enum arm_smccc_conduit conduit;
+	struct acpi_ffh_data *ffh_ctxt;
+
+	if (arm_smccc_get_version() < ARM_SMCCC_VERSION_1_2)
+		return -EOPNOTSUPP;
+
+	conduit = arm_smccc_1_1_get_conduit();
+	if (conduit == SMCCC_CONDUIT_NONE) {
+		pr_err("%s: invalid SMCCC conduit\n", __func__);
+		return -EOPNOTSUPP;
+	}
+
+	ffh_ctxt = kzalloc(sizeof(*ffh_ctxt), GFP_KERNEL);
+	if (!ffh_ctxt)
+		return -ENOMEM;
+
+	if (conduit == SMCCC_CONDUIT_SMC) {
+		ffh_ctxt->invoke_ffh_fn = __arm_smccc_smc;
+		ffh_ctxt->invoke_ffh64_fn = arm_smccc_1_2_smc;
+	} else {
+		ffh_ctxt->invoke_ffh_fn = __arm_smccc_hvc;
+		ffh_ctxt->invoke_ffh64_fn = arm_smccc_1_2_hvc;
+	}
+
+	memcpy(ffh_ctxt, handler_ctxt, sizeof(ffh_ctxt->info));
+
+	*region_ctxt = ffh_ctxt;
+	return AE_OK;
+}
+
+static bool acpi_ffh_smccc_owner_allowed(u32 fid)
+{
+	int owner = ARM_SMCCC_OWNER_NUM(fid);
+
+	if (owner == ARM_SMCCC_OWNER_STANDARD ||
+	    owner == ARM_SMCCC_OWNER_SIP || owner == ARM_SMCCC_OWNER_OEM)
+		return true;
+
+	return false;
+}
+
+int acpi_ffh_address_space_arch_handler(acpi_integer *value, void *region_context)
+{
+	int ret = 0;
+	struct acpi_ffh_data *ffh_ctxt = region_context;
+
+	if (ffh_ctxt->info.offset == 0) {
+		/* SMC/HVC 32bit call */
+		struct arm_smccc_res res;
+		u32 a[8] = { 0 }, *ptr = (u32 *)value;
+
+		if (!ARM_SMCCC_IS_FAST_CALL(*ptr) || ARM_SMCCC_IS_64(*ptr) ||
+		    !acpi_ffh_smccc_owner_allowed(*ptr) ||
+		    ffh_ctxt->info.length > 32) {
+			ret = AE_ERROR;
+		} else {
+			int idx, len = ffh_ctxt->info.length >> 2;
+
+			for (idx = 0; idx < len; idx++)
+				a[idx] = *(ptr + idx);
+
+			ffh_ctxt->invoke_ffh_fn(a[0], a[1], a[2], a[3], a[4],
+						a[5], a[6], a[7], &res, NULL);
+			memcpy(value, &res, sizeof(res));
+		}
+
+	} else if (ffh_ctxt->info.offset == 1) {
+		/* SMC/HVC 64bit call */
+		struct arm_smccc_1_2_regs *r = (struct arm_smccc_1_2_regs *)value;
+
+		if (!ARM_SMCCC_IS_FAST_CALL(r->a0) || !ARM_SMCCC_IS_64(r->a0) ||
+		    !acpi_ffh_smccc_owner_allowed(r->a0) ||
+		    ffh_ctxt->info.length > sizeof(*r)) {
+			ret = AE_ERROR;
+		} else {
+			ffh_ctxt->invoke_ffh64_fn(r, r);
+			memcpy(value, r, ffh_ctxt->info.length);
+		}
+	} else {
+		ret = AE_ERROR;
+	}
+
+	return ret;
+}