* [PATCH v11 1/2] dt-bindings: mailbox: add binding doc for the ARM SMC/HVC mailbox
2019-12-02 10:14 [PATCH v11 0/2] mailbox: arm: introduce smc triggered mailbox Peng Fan
@ 2019-12-02 10:14 ` Peng Fan
2019-12-02 10:14 ` [PATCH v11 2/2] mailbox: introduce ARM SMC based mailbox Peng Fan
1 sibling, 0 replies; 5+ messages in thread
From: Peng Fan @ 2019-12-02 10:14 UTC (permalink / raw)
To: robh+dt, mark.rutland, jassisinghbrar, sudeep.holla,
andre.przywara, f.fainelli
Cc: devicetree, linux-kernel, linux-arm-kernel, dl-linux-imx, Peng Fan
From: Peng Fan <peng.fan@nxp.com>
The ARM SMC/HVC mailbox binding describes a firmware interface to trigger
actions in software layers running in the EL2 or EL3 exception levels.
The term "ARM" here relates to the SMC instruction as part of the ARM
instruction set, not as a standard endorsed by ARM Ltd.
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
---
.../devicetree/bindings/mailbox/arm-smc.yaml | 96 ++++++++++++++++++++++
1 file changed, 96 insertions(+)
create mode 100644 Documentation/devicetree/bindings/mailbox/arm-smc.yaml
diff --git a/Documentation/devicetree/bindings/mailbox/arm-smc.yaml b/Documentation/devicetree/bindings/mailbox/arm-smc.yaml
new file mode 100644
index 000000000000..c165946a64e4
--- /dev/null
+++ b/Documentation/devicetree/bindings/mailbox/arm-smc.yaml
@@ -0,0 +1,96 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/mailbox/arm-smc.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: ARM SMC Mailbox Interface
+
+maintainers:
+ - Peng Fan <peng.fan@nxp.com>
+
+description: |
+ This mailbox uses the ARM smc (secure monitor call) or hvc (hypervisor
+ call) instruction to trigger a mailbox-connected activity in firmware,
+ executing on the very same core as the caller. The value of r0/w0/x0
+ the firmware returns after the smc call is delivered as a received
+ message to the mailbox framework, so synchronous communication can be
+ established. The exact meaning of the action the mailbox triggers as
+ well as the return value is defined by their users and is not subject
+ to this binding.
+
+ One example use case of this mailbox is the SCMI interface, which uses
+ shared memory to transfer commands and parameters, and a mailbox to
+ trigger a function call. This allows SoCs without a separate management
+ processor (or when such a processor is not available or used) to use
+ this standardized interface anyway.
+
+ This binding describes no hardware, but establishes a firmware interface.
+ Upon receiving an SMC using the described SMC function identifier, the
+ firmware is expected to trigger some mailbox connected functionality.
+ The communication follows the ARM SMC calling convention.
+ Firmware expects an SMC function identifier in r0 or w0. The supported
+ identifier is listed in the the arm,func-id property as described below.
+ The firmware can return one value in the first SMC result register,
+ it is expected to be an error value, which shall be propagated to the
+ mailbox client.
+
+ Any core which supports the SMC or HVC instruction can be used, as long
+ as a firmware component running in EL3 or EL2 is handling these calls.
+
+properties:
+ compatible:
+ oneOf:
+ - description:
+ For implementations using ARM SMC instruction.
+ const: arm,smc-mbox
+
+ - description:
+ For implementations using ARM HVC instruction.
+ const: arm,hvc-mbox
+
+ "#mbox-cells":
+ const: 0
+
+ arm,func-id:
+ description: |
+ An single 32-bit value specifying the function ID used by the mailbox.
+ The function ID follows the ARM SMC calling convention standard.
+ $ref: /schemas/types.yaml#/definitions/uint32
+
+required:
+ - compatible
+ - "#mbox-cells"
+ - arm,func-id
+
+examples:
+ - |
+ sram@93f000 {
+ compatible = "mmio-sram";
+ reg = <0x0 0x93f000 0x0 0x1000>;
+ #address-cells = <1>;
+ #size-cells = <1>;
+ ranges = <0x0 0x93f000 0x1000>;
+
+ cpu_scp_lpri: scp-shmem@0 {
+ compatible = "arm,scmi-shmem";
+ reg = <0x0 0x200>;
+ };
+ };
+
+ smc_tx_mbox: tx_mbox {
+ #mbox-cells = <0>;
+ compatible = "arm,smc-mbox";
+ arm,func-id = <0xc20000fe>;
+ };
+
+ firmware {
+ scmi {
+ compatible = "arm,scmi";
+ mboxes = <&smc_tx_mbox>;
+ mbox-names = "tx";
+ shmem = <&cpu_scp_lpri>;
+ };
+ };
+
+...
--
2.16.4
^ permalink raw reply related [flat|nested] 5+ messages in thread* [PATCH v11 2/2] mailbox: introduce ARM SMC based mailbox
2019-12-02 10:14 [PATCH v11 0/2] mailbox: arm: introduce smc triggered mailbox Peng Fan
2019-12-02 10:14 ` [PATCH v11 1/2] dt-bindings: mailbox: add binding doc for the ARM SMC/HVC mailbox Peng Fan
@ 2019-12-02 10:14 ` Peng Fan
2019-12-03 11:46 ` Sudeep Holla
1 sibling, 1 reply; 5+ messages in thread
From: Peng Fan @ 2019-12-02 10:14 UTC (permalink / raw)
To: robh+dt, mark.rutland, jassisinghbrar, sudeep.holla,
andre.przywara, f.fainelli
Cc: devicetree, linux-kernel, linux-arm-kernel, dl-linux-imx, Peng Fan
From: Peng Fan <peng.fan@nxp.com>
This mailbox driver implements a mailbox which signals transmitted data
via an ARM smc (secure monitor call) instruction. The mailbox receiver
is implemented in firmware and can synchronously return data when it
returns execution to the non-secure world again.
An asynchronous receive path is not implemented.
This allows the usage of a mailbox to trigger firmware actions on SoCs
which either don't have a separate management processor or on which such
a core is not available. A user of this mailbox could be the SCP
interface.
Modified from Andre Przywara's v2 patch
https://lore.kernel.org/patchwork/patch/812999/
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
---
drivers/mailbox/Kconfig | 7 ++
drivers/mailbox/Makefile | 2 +
drivers/mailbox/arm-smc-mailbox.c | 156 +++++++++++++++++++++++++++++++++
include/linux/mailbox/arm-smccc-mbox.h | 17 ++++
4 files changed, 182 insertions(+)
create mode 100644 drivers/mailbox/arm-smc-mailbox.c
create mode 100644 include/linux/mailbox/arm-smccc-mbox.h
diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig
index ab4eb750bbdd..7707ee26251a 100644
--- a/drivers/mailbox/Kconfig
+++ b/drivers/mailbox/Kconfig
@@ -16,6 +16,13 @@ config ARM_MHU
The controller has 3 mailbox channels, the last of which can be
used in Secure mode only.
+config ARM_SMC_MBOX
+ tristate "Generic ARM smc mailbox"
+ depends on OF && HAVE_ARM_SMCCC
+ help
+ Generic mailbox driver which uses ARM smc calls to call into
+ firmware for triggering mailboxes.
+
config IMX_MBOX
tristate "i.MX Mailbox"
depends on ARCH_MXC || COMPILE_TEST
diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile
index c22fad6f696b..93918a84c91b 100644
--- a/drivers/mailbox/Makefile
+++ b/drivers/mailbox/Makefile
@@ -7,6 +7,8 @@ obj-$(CONFIG_MAILBOX_TEST) += mailbox-test.o
obj-$(CONFIG_ARM_MHU) += arm_mhu.o
+obj-$(CONFIG_ARM_SMC_MBOX) += arm-smc-mailbox.o
+
obj-$(CONFIG_IMX_MBOX) += imx-mailbox.o
obj-$(CONFIG_ARMADA_37XX_RWTM_MBOX) += armada-37xx-rwtm-mailbox.o
diff --git a/drivers/mailbox/arm-smc-mailbox.c b/drivers/mailbox/arm-smc-mailbox.c
new file mode 100644
index 000000000000..223d46fe6513
--- /dev/null
+++ b/drivers/mailbox/arm-smc-mailbox.c
@@ -0,0 +1,156 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2016,2017 ARM Ltd.
+ * Copyright 2019 NXP
+ */
+
+#include <linux/arm-smccc.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/mailbox_controller.h>
+#include <linux/mailbox/arm-smccc-mbox.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+typedef unsigned long (smc_mbox_fn)(unsigned int, unsigned long,
+ unsigned long, unsigned long,
+ unsigned long, unsigned long,
+ unsigned long);
+
+struct arm_smc_chan_data {
+ unsigned int function_id;
+ smc_mbox_fn *invoke_smc_mbox_fn;
+};
+
+static int arm_smc_send_data(struct mbox_chan *link, void *data)
+{
+ struct arm_smc_chan_data *chan_data = link->con_priv;
+ struct arm_smccc_mbox_cmd *cmd = data;
+ unsigned long ret;
+
+ ret = chan_data->invoke_smc_mbox_fn(chan_data->function_id,
+ cmd->args_smccc[0],
+ cmd->args_smccc[1],
+ cmd->args_smccc[2],
+ cmd->args_smccc[3],
+ cmd->args_smccc[4],
+ cmd->args_smccc[5]);
+
+ mbox_chan_received_data(link, (void *)ret);
+
+ return 0;
+}
+
+static unsigned long __invoke_fn_hvc(unsigned int function_id,
+ unsigned long arg0, unsigned long arg1,
+ unsigned long arg2, unsigned long arg3,
+ unsigned long arg4, unsigned long arg5)
+{
+ struct arm_smccc_res res;
+
+ arm_smccc_hvc(function_id, arg0, arg1, arg2, arg3, arg4,
+ arg5, 0, &res);
+ return res.a0;
+}
+
+static unsigned long __invoke_fn_smc(unsigned int function_id,
+ unsigned long arg0, unsigned long arg1,
+ unsigned long arg2, unsigned long arg3,
+ unsigned long arg4, unsigned long arg5)
+{
+ struct arm_smccc_res res;
+
+ arm_smccc_smc(function_id, arg0, arg1, arg2, arg3, arg4,
+ arg5, 0, &res);
+ return res.a0;
+}
+
+static const struct mbox_chan_ops arm_smc_mbox_chan_ops = {
+ .send_data = arm_smc_send_data,
+};
+
+static struct mbox_chan *
+arm_smc_mbox_of_xlate(struct mbox_controller *mbox,
+ const struct of_phandle_args *sp)
+{
+ return mbox->chans;
+}
+
+static int arm_smc_mbox_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct mbox_controller *mbox;
+ struct arm_smc_chan_data *chan_data;
+ int ret;
+
+ mbox = devm_kzalloc(dev, sizeof(*mbox), GFP_KERNEL);
+ if (!mbox)
+ return -ENOMEM;
+
+ mbox->of_xlate = arm_smc_mbox_of_xlate;
+ mbox->num_chans = 1;
+ mbox->chans = devm_kzalloc(dev, sizeof(*mbox->chans), GFP_KERNEL);
+ if (!mbox->chans)
+ return -ENOMEM;
+
+ chan_data = devm_kzalloc(dev, sizeof(*chan_data), GFP_KERNEL);
+ if (!chan_data)
+ return -ENOMEM;
+
+ ret = of_property_read_u32(dev->of_node, "arm,func-id",
+ &chan_data->function_id);
+ if (ret)
+ return ret;
+
+ if (of_device_is_compatible(dev->of_node, "arm,smc-mbox"))
+ chan_data->invoke_smc_mbox_fn = __invoke_fn_smc;
+ else
+ chan_data->invoke_smc_mbox_fn = __invoke_fn_hvc;
+
+
+ mbox->chans->con_priv = chan_data;
+
+ mbox->txdone_poll = false;
+ mbox->txdone_irq = false;
+ mbox->ops = &arm_smc_mbox_chan_ops;
+ mbox->dev = dev;
+
+ platform_set_drvdata(pdev, mbox);
+
+ ret = devm_mbox_controller_register(dev, mbox);
+ if (ret)
+ return ret;
+
+ dev_info(dev, "ARM SMC mailbox enabled.\n");
+
+ return ret;
+}
+
+static int arm_smc_mbox_remove(struct platform_device *pdev)
+{
+ struct mbox_controller *mbox = platform_get_drvdata(pdev);
+
+ mbox_controller_unregister(mbox);
+ return 0;
+}
+
+static const struct of_device_id arm_smc_mbox_of_match[] = {
+ { .compatible = "arm,smc-mbox", },
+ { .compatible = "arm,hvc-mbox", },
+ {},
+};
+MODULE_DEVICE_TABLE(of, arm_smc_mbox_of_match);
+
+static struct platform_driver arm_smc_mbox_driver = {
+ .driver = {
+ .name = "arm-smc-mbox",
+ .of_match_table = arm_smc_mbox_of_match,
+ },
+ .probe = arm_smc_mbox_probe,
+ .remove = arm_smc_mbox_remove,
+};
+module_platform_driver(arm_smc_mbox_driver);
+
+MODULE_AUTHOR("Peng Fan <peng.fan@nxp.com>");
+MODULE_DESCRIPTION("Generic ARM smc mailbox driver");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/mailbox/arm-smccc-mbox.h b/include/linux/mailbox/arm-smccc-mbox.h
new file mode 100644
index 000000000000..244e09598c10
--- /dev/null
+++ b/include/linux/mailbox/arm-smccc-mbox.h
@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef _LINUX_ARM_SMCCC_MBOX_H_
+#define _LINUX_ARM_SMCCC_MBOX_H_
+
+#include <linux/types.h>
+
+/**
+ * struct arm_smccc_mbox_cmd - ARM SMCCC message structure
+ * @args_smccc: actual usage of registers is up to the protocol
+ * (within the SMCCC limits)
+ */
+struct arm_smccc_mbox_cmd {
+ unsigned long args_smccc[6];
+};
+
+#endif /* _LINUX_ARM_SMCCC_MBOX_H_ */
--
2.16.4
^ permalink raw reply related [flat|nested] 5+ messages in thread