From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751726AbdGBFzy (ORCPT ); Sun, 2 Jul 2017 01:55:54 -0400 Received: from mail-wm0-f66.google.com ([74.125.82.66]:34854 "EHLO mail-wm0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751065AbdGBFzw (ORCPT ); Sun, 2 Jul 2017 01:55:52 -0400 MIME-Version: 1.0 In-Reply-To: <20170630095608.24943-2-andre.przywara@arm.com> References: <20170630095608.24943-1-andre.przywara@arm.com> <20170630095608.24943-2-andre.przywara@arm.com> From: Jassi Brar Date: Sun, 2 Jul 2017 11:25:50 +0530 Message-ID: Subject: Re: [PATCH 1/8] mailbox: introduce ARM SMC based mailbox To: Andre Przywara Cc: Sudeep Holla , "linux-arm-kernel@lists.infradead.org" , Linux Kernel Mailing List , linux-sunxi@googlegroups.com, Maxime Ripard , Chen-Yu Tsai , Icenowy Zheng , Rob Herring , Mark Rutland , Devicetree List Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jun 30, 2017 at 3:26 PM, Andre Przywara wrote: > 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. > > Signed-off-by: Andre Przywara > --- > drivers/mailbox/Kconfig | 8 ++ > drivers/mailbox/Makefile | 2 + > drivers/mailbox/arm-smc-mailbox.c | 172 ++++++++++++++++++++++++++++++++++++++ > 3 files changed, 182 insertions(+) > create mode 100644 drivers/mailbox/arm-smc-mailbox.c > > diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig > index c5731e5..5664b7f 100644 > --- a/drivers/mailbox/Kconfig > +++ b/drivers/mailbox/Kconfig > @@ -170,4 +170,12 @@ config BCM_FLEXRM_MBOX > Mailbox implementation of the Broadcom FlexRM ring manager, > which provides access to various offload engines on Broadcom > SoCs. Say Y here if you want to use the Broadcom FlexRM. > + > +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. > + > endif > diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile > index d54e412..8ec6869 100644 > --- a/drivers/mailbox/Makefile > +++ b/drivers/mailbox/Makefile > @@ -35,3 +35,5 @@ obj-$(CONFIG_BCM_FLEXRM_MBOX) += bcm-flexrm-mailbox.o > obj-$(CONFIG_QCOM_APCS_IPC) += qcom-apcs-ipc-mailbox.o > > obj-$(CONFIG_TEGRA_HSP_MBOX) += tegra-hsp.o > + > +obj-$(CONFIG_ARM_SMC_MBOX) += arm-smc-mailbox.o > diff --git a/drivers/mailbox/arm-smc-mailbox.c b/drivers/mailbox/arm-smc-mailbox.c > new file mode 100644 > index 0000000..578aed2 > --- /dev/null > +++ b/drivers/mailbox/arm-smc-mailbox.c > @@ -0,0 +1,172 @@ > +/* > + * Copyright (C) 2016,2017 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 device provides a mechanism for emulating a mailbox by using > + * smc calls, allowing a "mailbox" consumer to sit in firmware running > + * on the same core. > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + Please have relook at what headers are really needed. > +#define ARM_SMC_MBOX_SMC (0 << 0) > +#define ARM_SMC_MBOX_HVC (1 << 0) > +#define ARM_SMC_MBOX_METHOD_MASK (1 << 0) > + Maybe have only #define ARM_SMC_MBOX_HVC BIT(0) > +struct arm_smc_chan_data { > + u32 function_id; > + u32 flags; > +}; > + > +static int arm_smc_send_data(struct mbox_chan *link, void *data) > +{ > + struct arm_smc_chan_data *chan_data = link->con_priv; > + u32 function_id = chan_data->function_id; > + struct arm_smccc_res res; > + u32 msg = *(u32 *)data; > + > + if ((chan_data->flags & ARM_SMC_MBOX_METHOD_MASK) == ARM_SMC_MBOX_SMC) > + arm_smccc_smc(function_id, msg, 0, 0, 0, 0, 0, 0, &res); > + else > + arm_smccc_hvc(function_id, msg, 0, 0, 0, 0, 0, 0, &res); > + if (chan_data->flags & ARM_SMC_MBOX_HVC) arm_smccc_hvc(function_id, msg, 0, 0, 0, 0, 0, 0, &res); else arm_smccc_smc(function_id, msg, 0, 0, 0, 0, 0, 0, &res); is simpler. > + mbox_chan_received_data(link, (void *)res.a0); > + Or you can update the 'data' with value from 'a0' ? > + return 0; > +} > + > +static int arm_smc_startup(struct mbox_chan *link) > +{ > + return 0; > +} > + > +static void arm_smc_shutdown(struct mbox_chan *link) > +{ > +} > + startup and shutdown can be omitted now. > +/* This mailbox is synchronous, so we are always done. */ > +static bool arm_smc_last_tx_done(struct mbox_chan *link) > +{ > + return true; > +} > + > +static const struct mbox_chan_ops arm_smc_mbox_chan_ops = { > + .send_data = arm_smc_send_data, > + .startup = arm_smc_startup, > + .shutdown = arm_smc_shutdown, > + .last_tx_done = arm_smc_last_tx_done > +}; > + > +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; > + const char *method; > + bool use_hvc = false; > + int ret = 0, i; > + No need to initialise 'ret' > + ret = of_property_count_elems_of_size(dev->of_node, "arm,smc-func-ids", > + sizeof(u32)); > + if (ret < 0) > + return ret; > + > + if (!of_property_read_string(dev->of_node, "method", &method)) { > + if (!strcmp("hvc", method)) { > + use_hvc = true; > + } else if (!strcmp("smc", method)) { > + use_hvc = false; > + } else { > + dev_warn(dev, "invalid \"method\" property: %s\n", > + method); > + > + return -EINVAL; > + } > + } > + > + mbox = devm_kzalloc(dev, sizeof(*mbox), GFP_KERNEL); > + if (!mbox) > + return -ENOMEM; > + > + mbox->num_chans = ret; > + mbox->chans = devm_kcalloc(dev, mbox->num_chans, sizeof(*mbox->chans), > + GFP_KERNEL); > + if (!mbox->chans) > + return -ENOMEM; > + > + chan_data = devm_kcalloc(dev, mbox->num_chans, sizeof(*chan_data), > + GFP_KERNEL); > + if (!chan_data) > + return -ENOMEM; > + > + for (i = 0; i < mbox->num_chans; i++) { > + u32 function_id; > + > + ret = of_property_read_u32_index(dev->of_node, > + "arm,smc-func-ids", i, > + &function_id); > + if (ret) > + return ret; > + > + chan_data[i].function_id = function_id; > + if (use_hvc) > + chan_data[i].flags |= ARM_SMC_MBOX_HVC; > + mbox->chans[i].con_priv = &chan_data[i]; > + } > + > + mbox->txdone_poll = true; > + mbox->txdone_irq = false; > + mbox->txpoll_period = 1; > + mbox->ops = &arm_smc_mbox_chan_ops; > + mbox->dev = dev; > + > + ret = mbox_controller_register(mbox); > + if (ret) > + return ret; > + > + platform_set_drvdata(pdev, mbox); > + dev_info(dev, "ARM SMC mailbox enabled with %d chan%s.\n", > + mbox->num_chans, mbox->num_chans == 1 ? "" : "s"); > + > + 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", }, > + {}, > +}; > +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("Andre Przywara "); > +MODULE_DESCRIPTION("Generic ARM smc mailbox driver"); > +MODULE_LICENSE("GPL v2"); > -- > 2.9.0 >