[PATCH 6/9] firmware: arm_ffa: Add initial Arm FFA driver support

Sudeep Holla
2020-08-29T17:11:41Z

This just add a basic driver that sets up the transport(e.g. SMCCC),
checks the FFA version implemented, get the partition ID for self and
sets up the Tx/Rx buffers for communication.

Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
---
drivers/firmware/arm_ffa/Makefile | 3 +-
drivers/firmware/arm_ffa/common.h | 23 +++
drivers/firmware/arm_ffa/driver.c | 288 ++++++++++++++++++++++++++++++
3 files changed, 313 insertions(+), 1 deletion(-)
create mode 100644 drivers/firmware/arm_ffa/common.h
create mode 100644 drivers/firmware/arm_ffa/driver.c

diff --git a/drivers/firmware/arm_ffa/Makefile b/drivers/firmware/arm_ffa/Makefile
index fadb325ee888..1a9bd2bf8752 100644
--- a/drivers/firmware/arm_ffa/Makefile
+++ b/drivers/firmware/arm_ffa/Makefile
@@ -1,3 +1,4 @@
# SPDX-License-Identifier: GPL-2.0-only
-obj-$(CONFIG_ARM_FFA_TRANSPORT) = ffa-bus.o
+obj-$(CONFIG_ARM_FFA_TRANSPORT) = ffa-bus.o ffa-driver.o
ffa-bus-y = bus.o
+ffa-driver-y = driver.o
diff --git a/drivers/firmware/arm_ffa/common.h b/drivers/firmware/arm_ffa/common.h
new file mode 100644
index 000000000000..720c8425dfd6
--- /dev/null
+++ b/drivers/firmware/arm_ffa/common.h
@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2020 ARM Ltd.
+ */
+
+#ifndef _FFA_COMMON_H
+#define _FFA_COMMON_H
+
+#include <linux/arm-smccc.h>
+#include <linux/err.h>
+
+typedef struct arm_smccc_v1_2_res ffa_res_t;
+
+typedef ffa_res_t
+(ffa_fn)(unsigned long, unsigned long, unsigned long, unsigned long,
+ unsigned long, unsigned long, unsigned long, unsigned long);
+
+static inline int __init ffa_transport_init(ffa_fn **invoke_ffa_fn)
+{
+ return -EOPNOTSUPP;
+}
+
+#endif /* _FFA_COMMON_H */
diff --git a/drivers/firmware/arm_ffa/driver.c b/drivers/firmware/arm_ffa/driver.c
new file mode 100644
index 000000000000..3670ba400f89
--- /dev/null
+++ b/drivers/firmware/arm_ffa/driver.c
@@ -0,0 +1,288 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Arm Firmware Framework for ARMv8-A(FFA) interface driver
+ *
+ * The Arm FFA specification[1] describes a software architecture to
+ * leverages the virtualization extension to isolate software images
+ * provided by an ecosystem of vendors from each other and describes
+ * interfaces that standardize communication between the various software
+ * images including communication between images in the Secure world and
+ * Normal world. Any Hypervisor could use the FFA interfaces to enable
+ * communication between VMs it manages.
+ *
+ * The Hypervisor a.k.a Partition managers in FFA terminology can assign
+ * system resources(Memory regions, Devices, CPU cycles) to the partitions
+ * and manage isolation amongst them.
+ *
+ * [1] https://developer.arm.com/docs/den0077/latest
+ *
+ * Copyright (C) 2020 Arm Ltd.
+ */
+
+#define DRIVER_NAME "ARM FF-A"
+#define pr_fmt(fmt) DRIVER_NAME ": " fmt
+
+#include <linux/bitfield.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/arm_ffa.h>
+
+#include "common.h"
+
+#define FFA_SMC(calling_convention, func_num) \
+ ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, (calling_convention), \
+ ARM_SMCCC_OWNER_STANDARD, (func_num))
+
+#define FFA_SMC_32(func_num) FFA_SMC(ARM_SMCCC_SMC_32, (func_num))
+#define FFA_SMC_64(func_num) FFA_SMC(ARM_SMCCC_SMC_64, (func_num))
+
+#define FFA_ERROR FFA_SMC_32(0x60)
+#define FFA_SUCCESS FFA_SMC_32(0x61)
+#define FFA_INTERRUPT FFA_SMC_32(0x62)
+#define FFA_VERSION FFA_SMC_32(0x63)
+#define FFA_FEATURES FFA_SMC_32(0x64)
+#define FFA_RX_RELEASE FFA_SMC_32(0x65)
+#define FFA_RXTX_MAP FFA_SMC_32(0x66)
+#define FFA_RXTX_UNMAP FFA_SMC_32(0x67)
+#define FFA_PARTITION_INFO_GET FFA_SMC_32(0x68)
+#define FFA_ID_GET FFA_SMC_32(0x69)
+#define FFA_MSG_POLL FFA_SMC_32(0x6A)
+#define FFA_MSG_WAIT FFA_SMC_32(0x6B)
+#define FFA_YIELD FFA_SMC_32(0x6C)
+#define FFA_RUN FFA_SMC_32(0x6D)
+#define FFA_MSG_SEND FFA_SMC_32(0x6E)
+#define FFA_MSG_SEND_DIRECT_REQ FFA_SMC_32(0x6F)
+#define FFA_FN64_MSG_SEND_DIRECT_REQ FFA_SMC_64(0x6F)
+#define FFA_MSG_SEND_DIRECT_RESP FFA_SMC_32(0x70)
+#define FFA_FN64_MSG_SEND_DIRECT_RESP FFA_SMC_64(0x70)
+#define FFA_MEM_DONATE FFA_SMC_32(0x71)
+#define FFA_FN64_MEM_DONATE FFA_SMC_32(0x71)
+#define FFA_MEM_LEND FFA_SMC_32(0x72)
+#define FFA_FN64_MEM_LEND FFA_SMC_32(0x72)
+#define FFA_MEM_SHARE FFA_SMC_32(0x73)
+#define FFA_FN64_MEM_SHARE FFA_SMC_64(0x73)
+#define FFA_MEM_RETRIEVE_REQ FFA_SMC_32(0x74)
+#define FFA_FN64_MEM_RETRIEVE_REQ FFA_SMC_64(0x74)
+#define FFA_MEM_RETRIEVE_RESP FFA_SMC_32(0x75)
+#define FFA_MEM_RELINQUISH FFA_SMC_32(0x76)
+#define FFA_MEM_RECLAIM FFA_SMC_32(0x77)
+#define FFA_MEM_OP_PAUSE FFA_SMC_32(0x78)
+#define FFA_MEM_OP_RESUME FFA_SMC_32(0x79)
+#define FFA_MEM_FRAG_RX FFA_SMC_32(0x7A)
+#define FFA_MEM_FRAG_TX FFA_SMC_32(0x7B)
+#define FFA_NORMAL_WORLD_RESUME FFA_SMC_32(0x7C)
+
+/*
+ * For some calls it is necessary to use SMC64 to pass or return 64-bit values.
+ * For such calls FFA_FN_NATIVE(name) will choose the appropriate
+ * (native-width) function ID.
+ */
+#ifdef CONFIG_64BIT
+#define FFA_FN_NATIVE(name) FFA_FN64_##name
+#else
+#define FFA_FN_NATIVE(name) FFA_##name
+#endif
+
+/* FFA error codes. */
+#define FFA_RET_SUCCESS (0)
+#define FFA_RET_NOT_SUPPORTED (-1)
+#define FFA_RET_INVALID_PARAMETERS (-2)
+#define FFA_RET_NO_MEMORY (-3)
+#define FFA_RET_BUSY (-4)
+#define FFA_RET_INTERRUPTED (-5)
+#define FFA_RET_DENIED (-6)
+#define FFA_RET_RETRY (-7)
+#define FFA_RET_ABORTED (-8)
+
+#define MAJOR_VERSION_MASK GENMASK(30, 16)
+#define MINOR_VERSION_MASK GENMASK(15, 0)
+#define MAJOR_VERSION(x) (u16)(FIELD_GET(MAJOR_VERSION_MASK, (x)))
+#define MINOR_VERSION(x) (u16)(FIELD_GET(MINOR_VERSION_MASK, (x)))
+#define PACK_VERSION_INFO(major, minor) \
+ (FIELD_PREP(MAJOR_VERSION_MASK, (major)) | \
+ FIELD_PREP(MINOR_VERSION_MASK, (minor)))
+#define FFA_VERSION_1_0 PACK_VERSION_INFO(1, 0)
+#define FFA_MIN_VERSION FFA_VERSION_1_0
+#define FFA_DRIVER_VERSION FFA_VERSION_1_0
+
+#define SENDER_ID_MASK GENMASK(31, 16)
+#define RECEIVER_ID_MASK GENMASK(15, 0)
+#define SENDER_ID(x) (u16)(FIELD_GET(SENDER_ID_MASK, (x)))
+#define RECEIVER_ID(x) (u16)(FIELD_GET(RECEIVER_ID_MASK, (x)))
+#define PACK_TARGET_INFO(s, r) \
+ (FIELD_PREP(SENDER_ID_MASK, (s)) | FIELD_PREP(RECEIVER_ID_MASK, (r)))
+
+/**
+ * FF-A specification mentions explicitly about '4K pages'. This should
+ * not be confused with the kernel PAGE_SIZE, which is the translation
+ * granule kernel is configured and may be one among 4K, 16K and 64K.
+ */
+#define FFA_PAGE_SIZE SZ_4K
+/* Keeping RX TX buffer size as 64K for now */
+#define RXTX_BUFFER_SIZE SZ_64K
+
+static ffa_fn *invoke_ffa_fn;
+
+static const int ffa_linux_errmap[] = {
+ /* better than switch case as long as return value is continuous */
+ 0, /* FFA_RET_SUCCESS */
+ -EOPNOTSUPP, /* FFA_RET_NOT_SUPPORTED */
+ -EINVAL, /* FFA_RET_INVALID_PARAMETERS */
+ -ENOMEM, /* FFA_RET_NO_MEMORY */
+ -EBUSY, /* FFA_RET_BUSY */
+ -EINTR, /* FFA_RET_INTERRUPTED */
+ -EACCES, /* FFA_RET_DENIED */
+ -EAGAIN, /* FFA_RET_RETRY */
+ -ECANCELED, /* FFA_RET_ABORTED */
+};
+
+static inline int ffa_to_linux_errno(int errno)
+{
+ if (errno < FFA_RET_SUCCESS && errno >= FFA_RET_ABORTED)
+ return ffa_linux_errmap[-errno];
+ return -EINVAL;
+}
+
+struct ffa_drv_info {
+ u32 version;
+ u16 vm_id;
+ struct mutex rx_lock; /* lock to protect Rx buffer */
+ struct mutex tx_lock; /* lock to protect Tx buffer */
+ void *rx_buffer;
+ void *tx_buffer;
+};
+
+static struct ffa_drv_info *drv_info;
+
+static int ffa_version_check(u32 *version)
+{
+ ffa_res_t ver;
+
+ ver = invoke_ffa_fn(FFA_VERSION, FFA_DRIVER_VERSION, 0, 0, 0, 0, 0, 0);
+
+ if (ver.a0 == FFA_RET_NOT_SUPPORTED) {
+ pr_info("FFA_VERSION returned not supported\n");
+ return -EOPNOTSUPP;
+ }
+
+ if (ver.a0 < FFA_MIN_VERSION || ver.a0 > FFA_DRIVER_VERSION) {
+ pr_err("Incompatible version %d.%d found\n",
+ MAJOR_VERSION(ver.a0), MINOR_VERSION(ver.a0));
+ return -EINVAL;
+ }
+
+ *version = ver.a0;
+ pr_info("Version %d.%d found\n", MAJOR_VERSION(ver.a0),
+ MINOR_VERSION(ver.a0));
+ return 0;
+}
+
+static int ffa_rxtx_map(phys_addr_t tx_buf, phys_addr_t rx_buf, u32 pg_cnt)
+{
+ ffa_res_t ret;
+
+ ret = invoke_ffa_fn(FFA_RXTX_MAP, tx_buf, rx_buf, pg_cnt, 0, 0, 0, 0);
+
+ if (ret.a0 == FFA_ERROR)
+ return ffa_to_linux_errno((int)ret.a2);
+
+ return 0;
+}
+
+static int ffa_rxtx_unmap(u16 vm_id)
+{
+ ffa_res_t ret;
+
+ ret = invoke_ffa_fn(FFA_RXTX_UNMAP, vm_id, 0, 0, 0, 0, 0, 0);
+
+ if (ret.a0 == FFA_ERROR)
+ return ffa_to_linux_errno((int)ret.a2);
+
+ return 0;
+}
+
+#define VM_ID_MASK GENMASK(15, 0)
+static int ffa_id_get(u16 *vm_id)
+{
+ ffa_res_t id;
+
+ id = invoke_ffa_fn(FFA_ID_GET, 0, 0, 0, 0, 0, 0, 0);
+
+ if (id.a0 == FFA_ERROR)
+ return ffa_to_linux_errno((int)id.a2);
+
+ *vm_id = FIELD_GET(VM_ID_MASK, (id.a2));
+
+ return 0;
+}
+
+static int __init ffa_init(void)
+{
+ int ret;
+
+ ret = ffa_transport_init(&invoke_ffa_fn);
+ if (ret)
+ return ret;
+
+ drv_info = kzalloc(sizeof(*drv_info), GFP_KERNEL);
+ if (!drv_info)
+ return -ENOMEM;
+
+ ret = ffa_version_check(&drv_info->version);
+ if (ret)
+ goto free_drv_info;
+
+ if (ffa_id_get(&drv_info->vm_id)) {
+ pr_err("failed to obtain VM id for self\n");
+ ret = -ENODEV;
+ goto free_drv_info;
+ }
+
+ drv_info->rx_buffer = alloc_pages_exact(RXTX_BUFFER_SIZE, GFP_KERNEL);
+ if (!drv_info->rx_buffer) {
+ ret = -ENOMEM;
+ goto free_pages;
+ }
+
+ drv_info->tx_buffer = alloc_pages_exact(RXTX_BUFFER_SIZE, GFP_KERNEL);
+ if (!drv_info->tx_buffer) {
+ ret = -ENOMEM;
+ goto free_pages;
+ }
+
+ ret = ffa_rxtx_map(virt_to_phys(drv_info->tx_buffer),
+ virt_to_phys(drv_info->rx_buffer),
+ RXTX_BUFFER_SIZE / FFA_PAGE_SIZE);
+ if (ret) {
+ pr_err("failed to register FFA RxTx buffers\n");
+ goto free_pages;
+ }
+
+ mutex_init(&drv_info->rx_lock);
+ mutex_init(&drv_info->tx_lock);
+
+ return 0;
+free_pages:
+ if (drv_info->tx_buffer)
+ free_pages_exact(drv_info->tx_buffer, RXTX_BUFFER_SIZE);
+ free_pages_exact(drv_info->rx_buffer, RXTX_BUFFER_SIZE);
+free_drv_info:
+ kfree(drv_info);
+ return ret;
+}
+module_init(ffa_init);
+
+static void __exit ffa_exit(void)
+{
+ ffa_rxtx_unmap(drv_info->vm_id);
+ free_pages_exact(drv_info->tx_buffer, RXTX_BUFFER_SIZE);
+ free_pages_exact(drv_info->rx_buffer, RXTX_BUFFER_SIZE);
+ kfree(drv_info);
+}
+module_exit(ffa_exit);
+
+MODULE_ALIAS("arm-ffa");
+MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
+MODULE_DESCRIPTION("Arm FF-A interface driver");
+MODULE_LICENSE("GPL v2");
--
2.17.1