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[2a01:cb05:8702:ff00:2dd4:25d:621b:504]) by smtp.gmail.com with ESMTPSA id c83sm20122796wmd.23.2020.04.15.03.59.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 15 Apr 2020 03:59:34 -0700 (PDT) Message-ID: <5e96e916.1c69fb81.14365.050b@mx.google.com> X-Google-Original-Message-ID: <1583673879-20714-3-git-send-email-peng.fan@nxp.com> (raw) From: Etienne Carriere To: peng.fan@nxp.com Cc: devicetree@vger.kernel.org, f.fainelli@gmail.com, linux-arm-kernel@lists.infradead.org, linux-imx@nxp.com, linux-kernel@vger.kernel.org, robh+dt@kernel.org, sudeep.holla@arm.com, viresh.kumar@linaro.org Subject: [PATCH V5 2/2] firmware: arm_scmi: add smc/hvc transport Date: Wed, 15 Apr 2020 12:58:58 +0200 X-Mailer: git-send-email 2.17.1 In-Reply-To: <1583673879-20714-3-git-send-email-peng.fan@nxp.com> References: <1583673879-20714-3-git-send-email-peng.fan@nxp.com> In-Reply-To: <1583673879-20714-1-git-send-email-peng.fan@nxp.com> Sender: devicetree-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org Hello Peng, I have 2 comments on this change. The main is about using arm_smccc_1_1_invoke(). Below some details and I added comments inside you patch. The second of on SMC return value, see my comment in your patch below. About arm_smccc_1_1_invoke(), this functon currently relies on PSCI driver to define a conduit method but SCMI agent driver does not mandate CONFIG_PSCI to be enable. Could you add an optional "method" property for "arm,scmi-smc" for platforms willing to not rely on PSCI Linux driver? If no property "method" is defined in the FDT, invocation relies on arm_smccc_1_1_invoke(). "method" naming mimics what is done in the OP-TEE driver (drivers/tee/optee/). Here is a proposal for the documenting property "method" in Documentation/arm,scmi.txt: - method : "smc" or "hvc" Optional property defining the conduit method for to be used for invoking the SCMI server in secure world. "smc" states instruction SMC #0 is used whereas "hvc" states instruction HVC #0 is used. Regards, Etienne > From: Peng Fan > > Take arm,smc-id as the 1st arg, leave the other args as zero for now. > There is no Rx, only Tx because of smc/hvc not support Rx. > > Signed-off-by: Peng Fan > > (...) > > diff --git a/drivers/firmware/arm_scmi/smc.c b/drivers/firmware/arm_scmi/smc.c > new file mode 100644 > index 000000000000..336168e40f49 > --- /dev/null > +++ b/drivers/firmware/arm_scmi/smc.c > @@ -0,0 +1,152 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * System Control and Management Interface (SCMI) Message SMC/HVC > + * Transport driver > + * > + * Copyright 2020 NXP > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +#include "common.h" > + > +/** > + * struct scmi_smc - Structure representing a SCMI smc transport > + * > + * @cinfo: SCMI channel info > + * @shmem: Transmit/Receive shared memory area > + * @func_id: smc/hvc call function id > + */ > + > +struct scmi_smc { > + struct scmi_chan_info *cinfo; > + struct scmi_shared_mem __iomem *shmem; > + u32 func_id; > +}; Add here a field for the secure world invocation function handler: scmi_arm_smccc_invoke_fn *invoke_fn; With function proto type defined: typedef void (scmi_arm_smccc_invoke_fn)(unsigned long, struct arm_smccc_res *); And materials to set the invocation hanlder: /* Simple wrapper functions to be able to use a function pointer */ static void _smccc_smc(unsigned long func_id, struct arm_smccc_res *res) { arm_smccc_smc(func_id, 0, 0, 0, 0, 0, 0, 0, res); } static void _smccc_hvc(unsigned long func_id, struct arm_smccc_res *res) { arm_smccc_hvc(func_id, 0, 0, 0, 0, 0, 0, 0, res); } static void _smccc_1_1(unsigned long func_id, struct arm_smccc_res *res) { arm_smccc_1_1_invoke(func_id, 0, 0, 0, 0, 0, 0, 0, res); } static scmi_arm_smccc_invoke_fn *get_invoke_function(struct device *dev) { const char *method; if (device_property_read_string(dev, "method", &method)) return _smccc_1_1; if (!strcmp("hvc", method)) return _smccc_hvc; if (!strcmp("smc", method)) return _smccc_smc; dev_err(dev, "Invalid \"method\" property: %s\n", method); return ERR_PTR(-EINVAL); } > + > +static DEFINE_MUTEX(smc_mutex); > + > +static bool smc_chan_available(struct device *dev, int idx) > +{ > + return true; > +} > + > +static int smc_chan_setup(struct scmi_chan_info *cinfo, struct device *dev, > + bool tx) > +{ > + struct device *cdev = cinfo->dev; > + struct scmi_smc *scmi_info; > + resource_size_t size; > + struct resource res; > + struct device_node *np; > + u32 func_id; > + int ret; > + > + if (!tx) > + return -ENODEV; > + > + scmi_info = devm_kzalloc(dev, sizeof(*scmi_info), GFP_KERNEL); > + if (!scmi_info) > + return -ENOMEM; > + > + np = of_parse_phandle(cdev->of_node, "shmem", 0> ); > + if (!np) > + np = of_parse_phandle(dev->of_node, "shmem", 0); > + ret = of_address_to_resource(np, 0, &res); > + of_node_put(np); > + if (ret) { > + dev_err(cdev, "failed to get SCMI Tx shared memory\n"); > + return ret; > + } > + > + size = resource_size(&res); > + scmi_info->shmem = devm_ioremap(dev, res.start, size); > + if (!scmi_info->shmem) { > + dev_err(dev, "failed to ioremap SCMI Tx shared memory\n"); > + return -EADDRNOTAVAIL; > + } > + > + ret = of_property_read_u32(dev->of_node, "arm,smc-id", &func_id); > + if (ret < 0) > + return ret; Here to get the handler for the invocation method: scmi_info->invoke_fn = get_invoke_function(dev); if (IS_ERR(scmi_info->invoke_fn)) return PTR_ERR(scmi_info->invoke_fn); > + > + scmi_info->func_id = func_id; > + scmi_info->cinfo = cinfo; > + cinfo->transport_info = scmi_info; > + > + return 0; > +} > + > +static int smc_chan_free(int id, void *p, void *data) > +{ > + struct scmi_chan_info *cinfo = p; > + struct scmi_smc *scmi_info = cinfo->transport_info; > + > + cinfo->transport_info = NULL; > + scmi_info->cinfo = NULL; > + > + scmi_free_channel(cinfo, data, id); > + > + return 0; > +} > + > +static int smc_send_message(struct scmi_chan_info *cinfo, > + struct scmi_xfer *xfer) > +{ > + struct scmi_smc *scmi_info = cinfo->transport_info; > + struct arm_smccc_res res; > + > + mutex_lock(&smc_mutex); > + > + shmem_tx_prepare(scmi_info->shmem, xfer); > + > + arm_smccc_1_1_invoke(scmi_info->func_id, 0, 0, 0, 0, 0, 0, 0, &res); Last, here would rahter call the registered handler instead: scmi_info->invoke_fn(scmi_info->func_id, &res); > + scmi_rx_callback(scmi_info->cinfo, shmem_read_header(scmi_info->shmem)); > + > + mutex_unlock(&smc_mutex); > + > + return res.a0; The SCMI server is likely not to return a errno compliant value. SMCCC specification states that unsupported function IDs should return signed extended -1. I suggest to change the return above with: return res.a0 == ~0 ? -EINVAL : 0; Regards, Etienne > +} > + > +static void smc_mark_txdone(struct scmi_chan_info *cinfo, int ret) > +{ > +} > + > +static void smc_fetch_response(struct scmi_chan_info *cinfo, > + struct scmi_xfer *xfer) > +{ > + struct scmi_smc *scmi_info = cinfo->transport_info; > + > + shmem_fetch_response(scmi_info->shmem, xfer); > +} > + > +static bool > +smc_poll_done(struct scmi_chan_info *cinfo, struct scmi_xfer *xfer) > +{ > + struct scmi_smc *scmi_info = cinfo->transport_info; > + > + return shmem_poll_done(scmi_info->shmem, xfer); > +} > + > +static struct scmi_transport_ops scmi_smc_ops = { > + .chan_available = smc_chan_available, > + .chan_setup = smc_chan_setup, > + .chan_free = smc_chan_free, > + .send_message = smc_send_message, > + .mark_txdone = smc_mark_txdone, > + .fetch_response = smc_fetch_response, > + .poll_done = smc_poll_done, > +}; > + > +const struct scmi_desc scmi_smc_desc = { > + .ops = &scmi_smc_ops, > + .max_rx_timeout_ms = 30, > + .max_msg = 1, > + .max_msg_size = 128, > +}; > -- > 2.16.4 > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel