optee: add per cpu asynchronous notification

Implements use of per-cpu irq for optee asynchronous notification.

Existing optee async notif implementation allows OP-TEE world to
raise an interrupt on which Linux optee driver will query some pending
events. This change allows the signaling interrupt to be a per-cpu
interrupt as with Arm GIC PPIs. Using a PPI instead of an SPI is useful
when no GIC lines are provisioned in the chip design and there are spare
PPI lines.

Cc: Jens Wiklander <jens.wiklander@linaro.org>
Cc: Sumit Garg <sumit.garg@linaro.org>
Cc: Marc Zyngier <maz@kernel.org>
Co-developed-by: Alexandre Torgue <alexandre.torgue@foss.st.com>
Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com>
Signed-off-by: Etienne Carriere <etienne.carriere@linaro.org>
Reviewed-by: Sumit Garg <sumit.garg@linaro.org>
[JW: fixing a spell error in @notif_pcpu_wq description]
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>

diff --git a/drivers/tee/optee/optee_private.h b/drivers/tee/optee/optee_private.h
index 04ae588..72685ee 100644 (file)
--- a/drivers/tee/optee/optee_private.h
+++ b/drivers/tee/optee/optee_private.h
@@ -94,11 +94,35 @@ struct optee_supp {
        struct completion reqs_c;
 };
 
+/*
+ * struct optee_pcpu - per cpu notif private struct passed to work functions
+ * @optee              optee device reference
+ */
+struct optee_pcpu {
+       struct optee *optee;
+};
+
+/*
+ * struct optee_smc - optee smc communication struct
+ * @invoke_fn          handler function to invoke secure monitor
+ * @memremaped_shm     virtual address of memory in shared memory pool
+ * @sec_caps:          secure world capabilities defined by
+ *                     OPTEE_SMC_SEC_CAP_* in optee_smc.h
+ * @notif_irq          interrupt used as async notification by OP-TEE or 0
+ * @optee_pcpu         per_cpu optee instance for per cpu work or NULL
+ * @notif_pcpu_wq      workqueue for per cpu asynchronous notification or NULL
+ * @notif_pcpu_work    work for per cpu asynchronous notification
+ * @notif_cpuhp_state   CPU hotplug state assigned for pcpu interrupt management
+ */
 struct optee_smc {
        optee_invoke_fn *invoke_fn;
        void *memremaped_shm;
        u32 sec_caps;
        unsigned int notif_irq;
+       struct optee_pcpu __percpu *optee_pcpu;
+       struct workqueue_struct *notif_pcpu_wq;
+       struct work_struct notif_pcpu_work;
+       unsigned int notif_cpuhp_state;
 };
 
 /**

diff --git a/drivers/tee/optee/smc_abi.c b/drivers/tee/optee/smc_abi.c
index a1c1fa1..de7ac9a 100644 (file)
--- a/drivers/tee/optee/smc_abi.c
+++ b/drivers/tee/optee/smc_abi.c
@@ -52,6 +52,23 @@
  */
 #define OPTEE_MIN_STATIC_POOL_ALIGN    9 /* 512 bytes aligned */
 
+/* SMC ABI considers at most a single TEE firmware */
+static unsigned int pcpu_irq_num;
+
+static int optee_cpuhp_enable_pcpu_irq(unsigned int cpu)
+{
+       enable_percpu_irq(pcpu_irq_num, IRQ_TYPE_NONE);
+
+       return 0;
+}
+
+static int optee_cpuhp_disable_pcpu_irq(unsigned int cpu)
+{
+       disable_percpu_irq(pcpu_irq_num);
+
+       return 0;
+}
+
 /*
  * 1. Convert between struct tee_param and struct optee_msg_param
  *
@@ -991,9 +1008,8 @@ static u32 get_async_notif_value(optee_invoke_fn *invoke_fn, bool *value_valid,
        return res.a1;
 }
 
-static irqreturn_t notif_irq_handler(int irq, void *dev_id)
+static irqreturn_t irq_handler(struct optee *optee)
 {
-       struct optee *optee = dev_id;
        bool do_bottom_half = false;
        bool value_valid;
        bool value_pending;
@@ -1016,6 +1032,13 @@ static irqreturn_t notif_irq_handler(int irq, void *dev_id)
        return IRQ_HANDLED;
 }
 
+static irqreturn_t notif_irq_handler(int irq, void *dev_id)
+{
+       struct optee *optee = dev_id;
+
+       return irq_handler(optee);
+}
+
 static irqreturn_t notif_irq_thread_fn(int irq, void *dev_id)
 {
        struct optee *optee = dev_id;
@@ -1025,7 +1048,7 @@ static irqreturn_t notif_irq_thread_fn(int irq, void *dev_id)
        return IRQ_HANDLED;
 }
 
-static int optee_smc_notif_init_irq(struct optee *optee, u_int irq)
+static int init_irq(struct optee *optee, u_int irq)
 {
        int rc;
 
@@ -1040,12 +1063,103 @@ static int optee_smc_notif_init_irq(struct optee *optee, u_int irq)
        return 0;
 }
 
+static irqreturn_t notif_pcpu_irq_handler(int irq, void *dev_id)
+{
+       struct optee_pcpu *pcpu = dev_id;
+       struct optee *optee = pcpu->optee;
+
+       if (irq_handler(optee) == IRQ_WAKE_THREAD)
+               queue_work(optee->smc.notif_pcpu_wq,
+                          &optee->smc.notif_pcpu_work);
+
+       return IRQ_HANDLED;
+}
+
+static void notif_pcpu_irq_work_fn(struct work_struct *work)
+{
+       struct optee_smc *optee_smc = container_of(work, struct optee_smc,
+                                                  notif_pcpu_work);
+       struct optee *optee = container_of(optee_smc, struct optee, smc);
+
+       optee_smc_do_bottom_half(optee->ctx);
+}
+
+static int init_pcpu_irq(struct optee *optee, u_int irq)
+{
+       struct optee_pcpu __percpu *optee_pcpu;
+       int cpu, rc;
+
+       optee_pcpu = alloc_percpu(struct optee_pcpu);
+       if (!optee_pcpu)
+               return -ENOMEM;
+
+       for_each_present_cpu(cpu)
+               per_cpu_ptr(optee_pcpu, cpu)->optee = optee;
+
+       rc = request_percpu_irq(irq, notif_pcpu_irq_handler,
+                               "optee_pcpu_notification", optee_pcpu);
+       if (rc)
+               goto err_free_pcpu;
+
+       INIT_WORK(&optee->smc.notif_pcpu_work, notif_pcpu_irq_work_fn);
+       optee->smc.notif_pcpu_wq = create_workqueue("optee_pcpu_notification");
+       if (!optee->smc.notif_pcpu_wq) {
+               rc = -EINVAL;
+               goto err_free_pcpu_irq;
+       }
+
+       optee->smc.optee_pcpu = optee_pcpu;
+       optee->smc.notif_irq = irq;
+
+       pcpu_irq_num = irq;
+       rc = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "optee/pcpu-notif:starting",
+                              optee_cpuhp_enable_pcpu_irq,
+                              optee_cpuhp_disable_pcpu_irq);
+       if (!rc)
+               rc = -EINVAL;
+       if (rc < 0)
+               goto err_free_pcpu_irq;
+
+       optee->smc.notif_cpuhp_state = rc;
+
+       return 0;
+
+err_free_pcpu_irq:
+       free_percpu_irq(irq, optee_pcpu);
+err_free_pcpu:
+       free_percpu(optee_pcpu);
+
+       return rc;
+}
+
+static int optee_smc_notif_init_irq(struct optee *optee, u_int irq)
+{
+       if (irq_is_percpu_devid(irq))
+               return init_pcpu_irq(optee, irq);
+       else
+               return init_irq(optee, irq);
+}
+
+static void uninit_pcpu_irq(struct optee *optee)
+{
+       cpuhp_remove_state(optee->smc.notif_cpuhp_state);
+
+       destroy_workqueue(optee->smc.notif_pcpu_wq);
+
+       free_percpu_irq(optee->smc.notif_irq, optee->smc.optee_pcpu);
+       free_percpu(optee->smc.optee_pcpu);
+}
+
 static void optee_smc_notif_uninit_irq(struct optee *optee)
 {
        if (optee->smc.sec_caps & OPTEE_SMC_SEC_CAP_ASYNC_NOTIF) {
                optee_smc_stop_async_notif(optee->ctx);
                if (optee->smc.notif_irq) {
-                       free_irq(optee->smc.notif_irq, optee);
+                       if (irq_is_percpu_devid(optee->smc.notif_irq))
+                               uninit_pcpu_irq(optee);
+                       else
+                               free_irq(optee->smc.notif_irq, optee);
+
                        irq_dispose_mapping(optee->smc.notif_irq);
                }
        }