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Sat, 14 Dec 2024 09:27:20 -0800 (PST) From: Anup Patel To: Thomas Gleixner Cc: Marc Zyngier , Shawn Guo , Sascha Hauer , Pengutronix Kernel Team , Andrew Lunn , Gregory Clement , Sebastian Hesselbarth , Palmer Dabbelt , Paul Walmsley , Atish Patra , Andrew Jones , Sunil V L , Anup Patel , linux-riscv@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, imx@lists.linux.dev, Anup Patel Subject: [PATCH v2 11/11] irqchip/riscv-imsic: Use IRQCHIP_MOVE_DEFERRED flag for PCI devices Date: Sat, 14 Dec 2024 22:55:49 +0530 Message-ID: <20241214172549.8842-12-apatel@ventanamicro.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20241214172549.8842-1-apatel@ventanamicro.com> References: <20241214172549.8842-1-apatel@ventanamicro.com> Precedence: bulk X-Mailing-List: imx@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Devices (such as PCI) which have non-atomic MSI update should migrate irq in the interrupt-context so use IRQCHIP_MOVE_DEFERRED flag for corresponding irqchips. The use of IRQCHIP_MOVE_DEFERRED further simplifies IMSIC vector movement as follows: 1) No need to handle the intermediate state seen by devices with non-atomic MSI update because imsic_irq_set_affinity() is called in the interrupt-context with interrupt masked. 2) No need to check temporary vector when completing vector movement on the old CPU in __imsic_local_sync(). 3) No need to call imsic_local_sync_all() from imsic_handle_irq() Signed-off-by: Anup Patel --- drivers/irqchip/irq-riscv-imsic-platform.c | 74 ++++++++++++++-------- drivers/irqchip/irq-riscv-imsic-state.c | 25 +------- 2 files changed, 50 insertions(+), 49 deletions(-) diff --git a/drivers/irqchip/irq-riscv-imsic-platform.c b/drivers/irqchip/irq-riscv-imsic-platform.c index e6c81718ba78..eac7f358bbba 100644 --- a/drivers/irqchip/irq-riscv-imsic-platform.c +++ b/drivers/irqchip/irq-riscv-imsic-platform.c @@ -64,6 +64,11 @@ static int imsic_irq_retrigger(struct irq_data *d) return 0; } +static void imsic_irq_ack(struct irq_data *d) +{ + irq_move_irq(d); +} + static void imsic_irq_compose_vector_msg(struct imsic_vector *vec, struct msi_msg *msg) { phys_addr_t msi_addr; @@ -97,7 +102,20 @@ static int imsic_irq_set_affinity(struct irq_data *d, const struct cpumask *mask bool force) { struct imsic_vector *old_vec, *new_vec; - struct imsic_vector tmp_vec; + + /* + * Requirements for the downstream irqdomains (or devices): + * + * 1) Downstream irqdomains (or devices) with atomic MSI update can + * happily do imsic_irq_set_affinity() in the process-context on + * any CPU so the irqchip of such irqdomains must not set the + * IRQCHIP_MOVE_DEFERRED flag. + * + * 2) Downstream irqdomains (or devices) with non-atomic MSI update + * must do imsic_irq_set_affinity() in the interrupt-context upon + * next interrupt so the irqchip of such irqdomains must set the + * IRQCHIP_MOVE_DEFERRED flag. + */ old_vec = irq_data_get_irq_chip_data(d); if (WARN_ON(!old_vec)) @@ -117,31 +135,13 @@ static int imsic_irq_set_affinity(struct irq_data *d, const struct cpumask *mask return -ENOSPC; /* - * Device having non-atomic MSI update might see an intermediate - * state when changing target IMSIC vector from one CPU to another. - * - * To avoid losing interrupt to some intermediate state, do the - * following (just like x86 APIC): - * - * 1) First write a temporary IMSIC vector to the device which - * has MSI address same as the old IMSIC vector but MSI data - * matches the new IMSIC vector. - * - * 2) Next write the new IMSIC vector to the device. - * - * Based on the above, the __imsic_local_sync() must check both - * old MSI data and new MSI data on the old CPU for pending + * Downstream irqdomains (or devices) with non-atomic MSI update + * may see an intermediate state when changing target IMSIC vector + * from one CPU to another but using the IRQCHIP_MOVE_DEFERRED + * flag this is taken care because imsic_irq_set_affinity() is + * called in the interrupt-context with interrupt masked. */ - if (new_vec->local_id != old_vec->local_id) { - /* Setup temporary vector */ - tmp_vec.cpu = old_vec->cpu; - tmp_vec.local_id = new_vec->local_id; - - /* Point device to the temporary vector */ - imsic_msi_update_msg(irq_get_irq_data(d->irq), &tmp_vec); - } - /* Point device to the new vector */ imsic_msi_update_msg(irq_get_irq_data(d->irq), new_vec); @@ -198,6 +198,7 @@ static struct irq_chip imsic_irq_base_chip = { .irq_force_complete_move = imsic_irq_force_complete_move, #endif .irq_retrigger = imsic_irq_retrigger, + .irq_ack = imsic_irq_ack, .irq_compose_msi_msg = imsic_irq_compose_msg, .flags = IRQCHIP_SKIP_SET_WAKE | IRQCHIP_MASK_ON_SUSPEND, @@ -217,7 +218,7 @@ static int imsic_irq_domain_alloc(struct irq_domain *domain, unsigned int virq, return -ENOSPC; irq_domain_set_info(domain, virq, virq, &imsic_irq_base_chip, vec, - handle_simple_irq, NULL, NULL); + handle_edge_irq, NULL, NULL); irq_set_noprobe(virq); irq_set_affinity(virq, cpu_online_mask); irq_data_update_effective_affinity(irq_get_irq_data(virq), cpumask_of(vec->cpu)); @@ -256,15 +257,36 @@ static const struct irq_domain_ops imsic_base_domain_ops = { #endif }; +static bool imsic_init_dev_msi_info(struct device *dev, + struct irq_domain *domain, + struct irq_domain *real_parent, + struct msi_domain_info *info) +{ + if (!msi_lib_init_dev_msi_info(dev, domain, real_parent, info)) + return false; + + switch (info->bus_token) { + case DOMAIN_BUS_PCI_DEVICE_MSI: + case DOMAIN_BUS_PCI_DEVICE_MSIX: + info->chip->flags |= IRQCHIP_MOVE_DEFERRED; + break; + default: + break; + } + + return true; +} + static const struct msi_parent_ops imsic_msi_parent_ops = { .supported_flags = MSI_GENERIC_FLAGS_MASK | MSI_FLAG_PCI_MSIX, .required_flags = MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS | MSI_FLAG_PCI_MSI_MASK_PARENT, + .chip_flags = MSI_CHIP_FLAG_SET_ACK, .bus_select_token = DOMAIN_BUS_NEXUS, .bus_select_mask = MATCH_PCI_MSI | MATCH_PLATFORM_MSI, - .init_dev_msi_info = msi_lib_init_dev_msi_info, + .init_dev_msi_info = imsic_init_dev_msi_info, }; int imsic_irqdomain_init(void) diff --git a/drivers/irqchip/irq-riscv-imsic-state.c b/drivers/irqchip/irq-riscv-imsic-state.c index aca769d915bf..c7649fb6bbe6 100644 --- a/drivers/irqchip/irq-riscv-imsic-state.c +++ b/drivers/irqchip/irq-riscv-imsic-state.c @@ -126,8 +126,8 @@ void __imsic_eix_update(unsigned long base_id, unsigned long num_id, bool pend, static bool __imsic_local_sync(struct imsic_local_priv *lpriv) { - struct imsic_local_config *tlocal, *mlocal; - struct imsic_vector *vec, *tvec, *mvec; + struct imsic_local_config *mlocal; + struct imsic_vector *vec, *mvec; bool ret = true; int i; @@ -170,27 +170,6 @@ static bool __imsic_local_sync(struct imsic_local_priv *lpriv) */ mvec = READ_ONCE(vec->move_next); if (mvec) { - /* - * Device having non-atomic MSI update might see an - * intermediate state so check both old ID and new ID - * for pending interrupts. - * - * For details, refer imsic_irq_set_affinity(). - */ - - tvec = vec->local_id == mvec->local_id ? - NULL : &lpriv->vectors[mvec->local_id]; - if (tvec && __imsic_id_read_clear_pending(tvec->local_id)) { - /* Retrigger temporary vector if it was already in-use */ - if (READ_ONCE(tvec->enable)) { - tlocal = per_cpu_ptr(imsic->global.local, tvec->cpu); - writel_relaxed(tvec->local_id, tlocal->msi_va); - } - - mlocal = per_cpu_ptr(imsic->global.local, mvec->cpu); - writel_relaxed(mvec->local_id, mlocal->msi_va); - } - if (__imsic_id_read_clear_pending(vec->local_id)) { mlocal = per_cpu_ptr(imsic->global.local, mvec->cpu); writel_relaxed(mvec->local_id, mlocal->msi_va);