┌───────┐ ┌──────────┐ │ │ │ │ ┌─────────────┐ │ │ │ PCI Host │ │ MSI │◄┐ │ │ │ │ │ Controller │ │ │ │ MSI Write │ │ └─────────────┘ └─┼───────┼───────────┼─BAR0 │ │ PCI │ │ BAR1 │ │ EP │ │ BAR2 │ │ │ │ BAR3 │ │ │ │ BAR4 │ │ ├──────────►│ │ └───────┘ └──────────┘ Linux supports endpoint functions. PCI RC write BAR<n> space like write to memory. The EP side can't know memory changed by the host driver. PCI Spec has not defined a standard method to do that. Only define MSI(x) to let EP notified RC status change. The basic idea is to trigger an IRQ when PCI RC writes to a memory address. That's what MSI controller provided. EP drivers just need to request a platform MSI interrupt, struct msi_msg *msg will pass down a memory address and data. EP driver will map such memory address to one of PCI BAR<n>. PCI RC writes to such memory to trigger EP side IRQ. Add MSI support for pci-epf-vntb. Query if system has an MSI controller. Set up doorbell address according to struct msi_msg. So PCI RC can write this doorbell address to trigger EP side's IRQ. If no MSI controller exists, fall back to software polling. Signed-off-by: Frank Li <Frank.Li@xxxxxxx> --- drivers/pci/endpoint/functions/pci-epf-vntb.c | 148 +++++++++++++++--- 1 file changed, 122 insertions(+), 26 deletions(-) diff --git a/drivers/pci/endpoint/functions/pci-epf-vntb.c b/drivers/pci/endpoint/functions/pci-epf-vntb.c index 1466dd1904175..f6e0b682da000 100644 --- a/drivers/pci/endpoint/functions/pci-epf-vntb.c +++ b/drivers/pci/endpoint/functions/pci-epf-vntb.c @@ -44,6 +44,7 @@ #include <linux/pci-epc.h> #include <linux/pci-epf.h> #include <linux/ntb.h> +#include <linux/msi.h> static struct workqueue_struct *kpcintb_workqueue; @@ -143,6 +144,8 @@ struct epf_ntb { void __iomem *vpci_mw_addr[MAX_MW]; struct delayed_work cmd_handler; + + int msi_virqbase; }; #define to_epf_ntb(epf_group) container_of((epf_group), struct epf_ntb, group) @@ -253,13 +256,15 @@ static void epf_ntb_cmd_handler(struct work_struct *work) ntb = container_of(work, struct epf_ntb, cmd_handler.work); - for (i = 1; i < ntb->db_count; i++) { - if (readl(ntb->epf_db + i * 4)) { - if (readl(ntb->epf_db + i * 4)) - ntb->db |= 1 << (i - 1); + if (!ntb->epf_db_phy) { + for (i = 1; i < ntb->db_count; i++) { + if (readl(ntb->epf_db + i * 4)) { + if (readl(ntb->epf_db + i * 4)) + ntb->db |= 1 << (i - 1); - ntb_db_event(&ntb->ntb, i); - writel(0, ntb->epf_db + i * 4); + ntb_db_event(&ntb->ntb, i); + writel(0, ntb->epf_db + i * 4); + } } } @@ -454,11 +459,9 @@ static int epf_ntb_config_spad_bar_alloc(struct epf_ntb *ntb) ctrl->num_mws = ntb->num_mws; ntb->spad_size = spad_size; - ctrl->db_entry_size = 4; - for (i = 0; i < ntb->db_count; i++) { ntb->reg->db_data[i] = 1 + i; - ntb->reg->db_offset[i] = 0; + ntb->reg->db_offset[i] = 4 * i; } return 0; @@ -509,6 +512,28 @@ static int epf_ntb_configure_interrupt(struct epf_ntb *ntb) return 0; } +static int epf_ntb_db_size(struct epf_ntb *ntb) +{ + const struct pci_epc_features *epc_features; + size_t size = 4 * ntb->db_count; + u32 align; + + epc_features = pci_epc_get_features(ntb->epf->epc, + ntb->epf->func_no, + ntb->epf->vfunc_no); + align = epc_features->align; + + if (size < 128) + size = 128; + + if (align) + size = ALIGN(size, align); + else + size = roundup_pow_of_two(size); + + return size; +} + /** * epf_ntb_db_bar_init() - Configure Doorbell window BARs * @ntb: NTB device that facilitates communication between HOST and vHOST @@ -522,33 +547,32 @@ static int epf_ntb_db_bar_init(struct epf_ntb *ntb) struct pci_epf_bar *epf_bar; void __iomem *mw_addr; enum pci_barno barno; - size_t size = 4 * ntb->db_count; + size_t size; epc_features = pci_epc_get_features(ntb->epf->epc, ntb->epf->func_no, ntb->epf->vfunc_no); align = epc_features->align; - - if (size < 128) - size = 128; - - if (align) - size = ALIGN(size, align); - else - size = roundup_pow_of_two(size); + size = epf_ntb_db_size(ntb); barno = ntb->epf_ntb_bar[BAR_DB]; + epf_bar = &ntb->epf->bar[barno]; - mw_addr = pci_epf_alloc_space(ntb->epf, size, barno, align, 0); - if (!mw_addr) { - dev_err(dev, "Failed to allocate OB address\n"); - return -ENOMEM; + if (ntb->epf_db_phy) { + mw_addr = NULL; + epf_bar->phys_addr = ntb->epf_db_phy; + epf_bar->barno = barno; + epf_bar->size = size; + } else { + mw_addr = pci_epf_alloc_space(ntb->epf, size, barno, align, 0); + if (!mw_addr) { + dev_err(dev, "Failed to allocate OB address\n"); + return -ENOMEM; + } } ntb->epf_db = mw_addr; - epf_bar = &ntb->epf->bar[barno]; - ret = pci_epc_set_bar(ntb->epf->epc, ntb->epf->func_no, ntb->epf->vfunc_no, epf_bar); if (ret) { dev_err(dev, "Doorbell BAR set failed\n"); @@ -704,6 +728,77 @@ static int epf_ntb_init_epc_bar(struct epf_ntb *ntb) return 0; } +static void epf_ntb_write_msi_msg(struct msi_desc *desc, struct msi_msg *msg) +{ + struct epf_ntb *ntb = dev_get_drvdata(desc->dev); + struct epf_ntb_ctrl *reg = ntb->reg; + int size = epf_ntb_db_size(ntb); + u64 addr; + + addr = msg->address_hi; + addr <<= 32; + addr |= msg->address_lo; + + reg->db_data[desc->msi_index] = msg->data; + + if (desc->msi_index == 0) + ntb->epf_db_phy = round_down(addr, size); + + reg->db_offset[desc->msi_index] = addr - ntb->epf_db_phy; +} + +static irqreturn_t epf_ntb_interrupt_handler(int irq, void *data) +{ + struct epf_ntb *ntb = data; + int index; + + index = irq - ntb->msi_virqbase; + ntb->db |= 1 << (index - 1); + ntb_db_event(&ntb->ntb, index); + + return IRQ_HANDLED; +} + +static void epf_ntb_epc_msi_init(struct epf_ntb *ntb) +{ + struct device *dev = &ntb->epf->dev; + struct irq_domain *domain; + int virq; + int ret; + int i; + + domain = dev_get_msi_domain(ntb->epf->epc->dev.parent); + if (!domain) + return; + + dev_set_msi_domain(dev, domain); + + if (platform_msi_domain_alloc_irqs(&ntb->epf->dev, + ntb->db_count, + epf_ntb_write_msi_msg)) { + dev_info(dev, "Can't allocate MSI, fall back to poll mode\n"); + return; + } + + dev_info(dev, "vntb use MSI as doorbell\n"); + + for (i = 0; i < ntb->db_count; i++) { + virq = msi_get_virq(dev, i); + ret = devm_request_irq(dev, virq, + epf_ntb_interrupt_handler, 0, + "ntb", ntb); + + if (ret) { + dev_err(dev, "devm_request_irq() failure, fall back to poll mode\n"); + ntb->epf_db_phy = 0; + break; + } + + if (!i) + ntb->msi_virqbase = virq; + } +} + /** * epf_ntb_epc_init() - Initialize NTB interface * @ntb: NTB device that facilitates communication between HOST and vHOST2 @@ -1299,14 +1394,15 @@ static int epf_ntb_bind(struct pci_epf *epf) goto err_bar_alloc; } + epf_set_drvdata(epf, ntb); + epf_ntb_epc_msi_init(ntb); + ret = epf_ntb_epc_init(ntb); if (ret) { dev_err(dev, "Failed to initialize EPC\n"); goto err_bar_alloc; } - epf_set_drvdata(epf, ntb); - pci_space[0] = (ntb->vntb_pid << 16) | ntb->vntb_vid; pci_vntb_table[0].vendor = ntb->vntb_vid; pci_vntb_table[0].device = ntb->vntb_pid; -- 2.35.1