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[104.188.17.28]) by smtp.gmail.com with ESMTPSA id y12sm13213948pgq.64.2019.03.25.14.09.26 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 25 Mar 2019 14:09:41 -0700 (PDT) Date: Mon, 25 Mar 2019 14:09:25 -0700 From: Bjorn Andersson To: Vivek Gautam Subject: Re: [PATCH v2 1/4] firmware: qcom_scm-64: Add atomic version of qcom_scm_call Message-ID: <20190325210925.GA2899@builder> References: <20180910062551.28175-1-vivek.gautam@codeaurora.org> <20180910062551.28175-2-vivek.gautam@codeaurora.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20180910062551.28175-2-vivek.gautam@codeaurora.org> User-Agent: Mutt/1.10.0 (2018-05-17) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190325_140950_155026_3F0C7FF9 X-CRM114-Status: GOOD ( 21.45 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: robdclark@gmail.com, joro@8bytes.org, will.deacon@arm.com, linux-kernel@vger.kernel.org, tfiga@chromium.org, david.brown@linaro.org, iommu@lists.linux-foundation.org, andy.gross@linaro.org, swboyd@chromium.org, robin.murphy@arm.com, linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Sun 09 Sep 23:25 PDT 2018, Vivek Gautam wrote: > There are scnenarios where drivers are required to make a > scm call in atomic context, such as in one of the qcom's > arm-smmu-500 errata [1]. > > [1] ("https://source.codeaurora.org/quic/la/kernel/msm-4.9/ > tree/drivers/iommu/arm-smmu.c?h=msm-4.9#n4842") > > Signed-off-by: Vivek Gautam Reviewed-by: Bjorn Andersson Regards, Bjorn > --- > drivers/firmware/qcom_scm-64.c | 136 ++++++++++++++++++++++++++++------------- > 1 file changed, 92 insertions(+), 44 deletions(-) > > diff --git a/drivers/firmware/qcom_scm-64.c b/drivers/firmware/qcom_scm-64.c > index 688525dd4aee..3a8c867cdf51 100644 > --- a/drivers/firmware/qcom_scm-64.c > +++ b/drivers/firmware/qcom_scm-64.c > @@ -70,32 +70,71 @@ static DEFINE_MUTEX(qcom_scm_lock); > #define FIRST_EXT_ARG_IDX 3 > #define N_REGISTER_ARGS (MAX_QCOM_SCM_ARGS - N_EXT_QCOM_SCM_ARGS + 1) > > -/** > - * qcom_scm_call() - Invoke a syscall in the secure world > - * @dev: device > - * @svc_id: service identifier > - * @cmd_id: command identifier > - * @desc: Descriptor structure containing arguments and return values > - * > - * Sends a command to the SCM and waits for the command to finish processing. > - * This should *only* be called in pre-emptible context. > -*/ > -static int qcom_scm_call(struct device *dev, u32 svc_id, u32 cmd_id, > - const struct qcom_scm_desc *desc, > - struct arm_smccc_res *res) > +static void __qcom_scm_call_do(const struct qcom_scm_desc *desc, > + struct arm_smccc_res *res, u32 fn_id, > + u64 x5, u32 type) > +{ > + u64 cmd; > + struct arm_smccc_quirk quirk = {.id = ARM_SMCCC_QUIRK_QCOM_A6}; > + > + cmd = ARM_SMCCC_CALL_VAL(type, qcom_smccc_convention, > + ARM_SMCCC_OWNER_SIP, fn_id); > + > + quirk.state.a6 = 0; > + > + do { > + arm_smccc_smc_quirk(cmd, desc->arginfo, desc->args[0], > + desc->args[1], desc->args[2], x5, > + quirk.state.a6, 0, res, &quirk); > + > + if (res->a0 == QCOM_SCM_INTERRUPTED) > + cmd = res->a0; > + > + } while (res->a0 == QCOM_SCM_INTERRUPTED); > +} > + > +static void qcom_scm_call_do(const struct qcom_scm_desc *desc, > + struct arm_smccc_res *res, u32 fn_id, > + u64 x5, bool atomic) > +{ > + int retry_count = 0; > + > + if (!atomic) { > + do { > + mutex_lock(&qcom_scm_lock); > + > + __qcom_scm_call_do(desc, res, fn_id, x5, > + ARM_SMCCC_STD_CALL); > + > + mutex_unlock(&qcom_scm_lock); > + > + if (res->a0 == QCOM_SCM_V2_EBUSY) { > + if (retry_count++ > QCOM_SCM_EBUSY_MAX_RETRY) > + break; > + msleep(QCOM_SCM_EBUSY_WAIT_MS); > + } > + } while (res->a0 == QCOM_SCM_V2_EBUSY); > + } else { > + __qcom_scm_call_do(desc, res, fn_id, x5, ARM_SMCCC_FAST_CALL); > + } > +} > + > +static int ___qcom_scm_call(struct device *dev, u32 svc_id, u32 cmd_id, > + const struct qcom_scm_desc *desc, > + struct arm_smccc_res *res, bool atomic) > { > int arglen = desc->arginfo & 0xf; > - int retry_count = 0, i; > + int i; > u32 fn_id = QCOM_SCM_FNID(svc_id, cmd_id); > - u64 cmd, x5 = desc->args[FIRST_EXT_ARG_IDX]; > + u64 x5 = desc->args[FIRST_EXT_ARG_IDX]; > dma_addr_t args_phys = 0; > void *args_virt = NULL; > size_t alloc_len; > - struct arm_smccc_quirk quirk = {.id = ARM_SMCCC_QUIRK_QCOM_A6}; > + gfp_t flag = atomic ? GFP_ATOMIC : GFP_KERNEL; > > if (unlikely(arglen > N_REGISTER_ARGS)) { > alloc_len = N_EXT_QCOM_SCM_ARGS * sizeof(u64); > - args_virt = kzalloc(PAGE_ALIGN(alloc_len), GFP_KERNEL); > + args_virt = kzalloc(PAGE_ALIGN(alloc_len), flag); > > if (!args_virt) > return -ENOMEM; > @@ -125,33 +164,7 @@ static int qcom_scm_call(struct device *dev, u32 svc_id, u32 cmd_id, > x5 = args_phys; > } > > - do { > - mutex_lock(&qcom_scm_lock); > - > - cmd = ARM_SMCCC_CALL_VAL(ARM_SMCCC_STD_CALL, > - qcom_smccc_convention, > - ARM_SMCCC_OWNER_SIP, fn_id); > - > - quirk.state.a6 = 0; > - > - do { > - arm_smccc_smc_quirk(cmd, desc->arginfo, desc->args[0], > - desc->args[1], desc->args[2], x5, > - quirk.state.a6, 0, res, &quirk); > - > - if (res->a0 == QCOM_SCM_INTERRUPTED) > - cmd = res->a0; > - > - } while (res->a0 == QCOM_SCM_INTERRUPTED); > - > - mutex_unlock(&qcom_scm_lock); > - > - if (res->a0 == QCOM_SCM_V2_EBUSY) { > - if (retry_count++ > QCOM_SCM_EBUSY_MAX_RETRY) > - break; > - msleep(QCOM_SCM_EBUSY_WAIT_MS); > - } > - } while (res->a0 == QCOM_SCM_V2_EBUSY); > + qcom_scm_call_do(desc, res, fn_id, x5, atomic); > > if (args_virt) { > dma_unmap_single(dev, args_phys, alloc_len, DMA_TO_DEVICE); > @@ -164,6 +177,41 @@ static int qcom_scm_call(struct device *dev, u32 svc_id, u32 cmd_id, > return 0; > } > > +/** > + * qcom_scm_call() - Invoke a syscall in the secure world > + * @dev: device > + * @svc_id: service identifier > + * @cmd_id: command identifier > + * @desc: Descriptor structure containing arguments and return values > + * > + * Sends a command to the SCM and waits for the command to finish processing. > + * This should *only* be called in pre-emptible context. > + */ > +static int qcom_scm_call(struct device *dev, u32 svc_id, u32 cmd_id, > + const struct qcom_scm_desc *desc, > + struct arm_smccc_res *res) > +{ > + return ___qcom_scm_call(dev, svc_id, cmd_id, desc, res, false); > +} > + > +/** > + * qcom_scm_call_atomic() - atomic variation of qcom_scm_call() > + * @dev: device > + * @svc_id: service identifier > + * @cmd_id: command identifier > + * @desc: Descriptor structure containing arguments and return values > + * @res: Structure containing results from SMC/HVC call > + * > + * Sends a command to the SCM and waits for the command to finish processing. > + * This should be called in atomic context only. > + */ > +static int qcom_scm_call_atomic(struct device *dev, u32 svc_id, u32 cmd_id, > + const struct qcom_scm_desc *desc, > + struct arm_smccc_res *res) > +{ > + return ___qcom_scm_call(dev, svc_id, cmd_id, desc, res, true); > +} > + > /** > * qcom_scm_set_cold_boot_addr() - Set the cold boot address for cpus > * @entry: Entry point function for the cpus > -- > QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member > of Code Aurora Forum, hosted by The Linux Foundation > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel