[PATCH v9 3/3] PCI: Add tango MSI controller support

Marc Gonzalez
2017-06-20T08:21:11Z

The MSI controller in Tango supports 256 message-signaled interrupts,
and a single doorbell address.

Signed-off-by: Marc Gonzalez <marc_gonzalez@sigmadesigns.com>
---
drivers/pci/host/pcie-tango.c | 226 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 226 insertions(+)

diff --git a/drivers/pci/host/pcie-tango.c b/drivers/pci/host/pcie-tango.c
index 67aaadcc1c5e..5c47a4cc03e3 100644
--- a/drivers/pci/host/pcie-tango.c
+++ b/drivers/pci/host/pcie-tango.c
@@ -1,16 +1,229 @@
+#include <linux/irqchip/chained_irq.h>
+#include <linux/irqdomain.h>
#include <linux/pci-ecam.h>
#include <linux/delay.h>
+#include <linux/msi.h>
#include <linux/of.h>

#define MSI_MAX 256

#define SMP8759_MUX 0x48
#define SMP8759_TEST_OUT 0x74
+#define SMP8759_STATUS 0x80
+#define SMP8759_ENABLE 0xa0
+#define SMP8759_DOORBELL 0xa002e07c

struct tango_pcie {
+ DECLARE_BITMAP(used_msi, MSI_MAX);
+ spinlock_t used_msi_lock;
void __iomem *mux;
+ void __iomem *msi_status;
+ void __iomem *msi_enable;
+ phys_addr_t msi_doorbell;
+ struct irq_domain *irq_dom;
+ struct irq_domain *msi_dom;
+ int irq;
};

+/*** MSI CONTROLLER SUPPORT ***/
+
+static void tango_msi_isr(struct irq_desc *desc)
+{
+ struct irq_chip *chip = irq_desc_get_chip(desc);
+ struct tango_pcie *pcie = irq_desc_get_handler_data(desc);
+ unsigned long status, base, virq, idx, pos = 0;
+
+ chained_irq_enter(chip, desc);
+ spin_lock(&pcie->used_msi_lock);
+
+ while ((pos = find_next_bit(pcie->used_msi, MSI_MAX, pos)) < MSI_MAX) {
+ base = round_down(pos, 32);
+ status = readl_relaxed(pcie->msi_status + base / 8);
+ for_each_set_bit(idx, &status, 32) {
+ virq = irq_find_mapping(pcie->irq_dom, base + idx);
+ generic_handle_irq(virq);
+ }
+ pos = base + 32;
+ }
+
+ spin_unlock(&pcie->used_msi_lock);
+ chained_irq_exit(chip, desc);
+}
+
+static void tango_ack(struct irq_data *d)
+{
+ struct tango_pcie *pcie = d->chip_data;
+ u32 offset = (d->hwirq / 32) * 4;
+ u32 bit = BIT(d->hwirq % 32);
+
+ writel_relaxed(bit, pcie->msi_status + offset);
+}
+
+static void update_msi_enable(struct irq_data *d, bool unmask)
+{
+ unsigned long flags;
+ struct tango_pcie *pcie = d->chip_data;
+ u32 offset = (d->hwirq / 32) * 4;
+ u32 bit = BIT(d->hwirq % 32);
+ u32 val;
+
+ spin_lock_irqsave(&pcie->used_msi_lock, flags);
+ val = readl_relaxed(pcie->msi_enable + offset);
+ val = unmask ? val | bit : val & ~bit;
+ writel_relaxed(val, pcie->msi_enable + offset);
+ spin_unlock_irqrestore(&pcie->used_msi_lock, flags);
+}
+
+static void tango_mask(struct irq_data *d)
+{
+ update_msi_enable(d, false);
+}
+
+static void tango_unmask(struct irq_data *d)
+{
+ update_msi_enable(d, true);
+}
+
+static int tango_set_affinity(struct irq_data *d,
+ const struct cpumask *mask, bool force)
+{
+ return -EINVAL;
+}
+
+static void tango_compose_msi_msg(struct irq_data *d, struct msi_msg *msg)
+{
+ struct tango_pcie *pcie = d->chip_data;
+ msg->address_lo = lower_32_bits(pcie->msi_doorbell);
+ msg->address_hi = upper_32_bits(pcie->msi_doorbell);
+ msg->data = d->hwirq;
+}
+
+static struct irq_chip tango_chip = {
+ .irq_ack = tango_ack,
+ .irq_mask = tango_mask,
+ .irq_unmask = tango_unmask,
+ .irq_set_affinity = tango_set_affinity,
+ .irq_compose_msi_msg = tango_compose_msi_msg,
+};
+
+static void msi_ack(struct irq_data *d)
+{
+ irq_chip_ack_parent(d);
+}
+
+static void msi_mask(struct irq_data *d)
+{
+ pci_msi_mask_irq(d);
+ irq_chip_mask_parent(d);
+}
+
+static void msi_unmask(struct irq_data *d)
+{
+ pci_msi_unmask_irq(d);
+ irq_chip_unmask_parent(d);
+}
+
+static struct irq_chip msi_chip = {
+ .name = "MSI",
+ .irq_ack = msi_ack,
+ .irq_mask = msi_mask,
+ .irq_unmask = msi_unmask,
+};
+
+static struct msi_domain_info msi_dom_info = {
+ .flags = MSI_FLAG_PCI_MSIX
+ | MSI_FLAG_USE_DEF_DOM_OPS
+ | MSI_FLAG_USE_DEF_CHIP_OPS,
+ .chip = &msi_chip,
+};
+
+static int tango_irq_domain_alloc(struct irq_domain *dom,
+ unsigned int virq, unsigned int nr_irqs, void *args)
+{
+ int pos;
+ unsigned long flags;
+ struct tango_pcie *pcie = dom->host_data;
+
+ spin_lock_irqsave(&pcie->used_msi_lock, flags);
+ pos = find_first_zero_bit(pcie->used_msi, MSI_MAX);
+ if (pos >= MSI_MAX) {
+ spin_unlock_irqrestore(&pcie->used_msi_lock, flags);
+ return -ENOSPC;
+ }
+ __set_bit(pos, pcie->used_msi);
+ spin_unlock_irqrestore(&pcie->used_msi_lock, flags);
+ irq_domain_set_info(dom, virq, pos, &tango_chip,
+ pcie, handle_edge_irq, NULL, NULL);
+
+ return 0;
+}
+
+static void tango_irq_domain_free(struct irq_domain *dom,
+ unsigned int virq, unsigned int nr_irqs)
+{
+ unsigned long flags;
+ struct irq_data *d = irq_domain_get_irq_data(dom, virq);
+ struct tango_pcie *pcie = d->chip_data;
+
+ spin_lock_irqsave(&pcie->used_msi_lock, flags);
+ __clear_bit(d->hwirq, pcie->used_msi);
+ spin_unlock_irqrestore(&pcie->used_msi_lock, flags);
+}
+
+static const struct irq_domain_ops irq_dom_ops = {
+ .alloc = tango_irq_domain_alloc,
+ .free = tango_irq_domain_free,
+};
+
+static int tango_msi_remove(struct platform_device *pdev)
+{
+ struct tango_pcie *pcie = platform_get_drvdata(pdev);
+
+ irq_set_chained_handler_and_data(pcie->irq, NULL, NULL);
+ irq_domain_remove(pcie->msi_dom);
+ irq_domain_remove(pcie->irq_dom);
+
+ return 0;
+}
+
+static int tango_msi_probe(struct platform_device *pdev, struct tango_pcie *pcie)
+{
+ int i, virq;
+ struct irq_domain *msi_dom, *irq_dom;
+ struct fwnode_handle *fwnode = of_node_to_fwnode(pdev->dev.of_node);
+
+ spin_lock_init(&pcie->used_msi_lock);
+ for (i = 0; i < MSI_MAX / 32; ++i)
+ writel_relaxed(0, pcie->msi_enable + i * 4);
+
+ virq = platform_get_irq(pdev, 1);
+ if (virq <= 0) {
+ pr_err("Failed to map IRQ\n");
+ return -ENXIO;
+ }
+
+ irq_dom = irq_domain_create_linear(fwnode, MSI_MAX, &irq_dom_ops, pcie);
+ if (!irq_dom) {
+ pr_err("Failed to create IRQ domain\n");
+ return -ENOMEM;
+ }
+
+ msi_dom = pci_msi_create_irq_domain(fwnode, &msi_dom_info, irq_dom);
+ if (!msi_dom) {
+ pr_err("Failed to create MSI domain\n");
+ irq_domain_remove(irq_dom);
+ return -ENOMEM;
+ }
+
+ pcie->irq_dom = irq_dom;
+ pcie->msi_dom = msi_dom;
+ pcie->irq = virq;
+
+ irq_set_chained_handler_and_data(virq, tango_msi_isr, pcie);
+
+ return 0;
+}
+
/*** HOST BRIDGE SUPPORT ***/

static int smp8759_config_read(struct pci_bus *bus,
@@ -88,6 +301,9 @@ static int tango_check_pcie_link(void __iomem *test_out)
static int smp8759_init(struct tango_pcie *pcie, void __iomem *base)
{
pcie->mux = base + SMP8759_MUX;
+ pcie->msi_status = base + SMP8759_STATUS;
+ pcie->msi_enable = base + SMP8759_ENABLE;
+ pcie->msi_doorbell = SMP8759_DOORBELL;

return tango_check_pcie_link(base + SMP8759_TEST_OUT);
}
@@ -121,11 +337,21 @@ static int tango_pcie_probe(struct platform_device *pdev)
if (ret)
return ret;

+ ret = tango_msi_probe(pdev, pcie);
+ if (ret)
+ return ret;
+
return pci_host_common_probe(pdev, &smp8759_ecam_ops);
}

+static int tango_pcie_remove(struct platform_device *pdev)
+{
+ return tango_msi_remove(pdev);
+}
+
static struct platform_driver tango_pcie_driver = {
.probe = tango_pcie_probe,
+ .remove = tango_pcie_remove,
.driver = {
.name = KBUILD_MODNAME,
.of_match_table = tango_pcie_ids,
--
2.11.0