FFH Operation Region space can be used to trigger SMC or HVC calls,
using the Arm SMC Calling Convention (SMCCC). The choice of conduit
(SMC or HVC) is based on what the kernel choose based on PSCI as with
any other users of SMCCC within the kernel.
Function identifiers only the SMCCC SiP Service, OEM Service and FF-A
specific call range.
Offset can be either 0(32 bit calling convention) or 1(64 bit calling
convention). The length must be set with the range applicable based
on the value of the offset.
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Signed-off-by: Sudeep Holla <sudeep.holla@xxxxxxx>
---
arch/arm64/kernel/acpi.c | 104 +++++++++++++++++++++++++++++++++++++++
1 file changed, 104 insertions(+)
diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
index e4dea8db6924..3eb64d443ab0 100644
--- a/arch/arm64/kernel/acpi.c
+++ b/arch/arm64/kernel/acpi.c
@@ -13,6 +13,7 @@
#define pr_fmt(fmt) "ACPI: " fmt
#include <linux/acpi.h>
+#include <linux/arm-smccc.h>
#include <linux/cpumask.h>
#include <linux/efi.h>
#include <linux/efi-bgrt.h>
@@ -411,3 +412,106 @@ void arch_reserve_mem_area(acpi_physical_address addr, size_t size)
{
memblock_mark_nomap(addr, size);
}
+
+#ifdef CONFIG_ACPI_FFH
+/*
+ * 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, unsigned long, unsigned long,
+ unsigned long, unsigned long, unsigned long,
+ unsigned long, unsigned long,
+ struct arm_smccc_res *, struct arm_smccc_quirk *);
+ void (*invoke_ffh64_fn)(const struct arm_smccc_1_2_regs *,
+ struct arm_smccc_1_2_regs *);
+};
+
+int acpi_ffh_address_space_arch_setup(void *handler_ctxt, void **region_ctxt)
+{
+ enum arm_smccc_conduit conduit;
+ struct acpi_ffh_data *ffh_ctxt;
+
+ ffh_ctxt = kzalloc(sizeof(*ffh_ctxt), GFP_KERNEL);
+ if (!ffh_ctxt)
+ return -ENOMEM;
+
+ 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;
+ }
+
+ 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;
+}
+#endif /* CONFIG_ACPI_FFH */
--
2.36.1
