On Sun, 01 Nov 2020 09:25:04 +0000,
Frank Wunderlich <fran...@public-files.de> wrote:
> 
> Am 31. Oktober 2020 22:49:14 MEZ schrieb Thomas Gleixner <t...@linutronix.de>:
> 
> >That's not a fix. It's just supressing the warning.
> 
> Ok sorry
> 
> >So it needs to be figured out why the domain association is not there.
> 
> It looks like for mt7623 there is no msi domain setup (done via
> mtk_pcie_setup_irq callback + mtk_pcie_init_irq_domain) in mtk pcie
> driver.

Does this mean that this SoC never handled MSIs the first place? Which
would explain the warning, as there is no MSI domain registered for
the device, and we end-up falling back to arch_setup_msi_irqs().

If this system truly is unable to handle MSIs, one potential
workaround would be to register a PCI-MSI domain that would always
fail its allocation with -ENOSPC. It is really ugly, but would keep
the horror localised. See the patchlet below, which I can't test.

If this situation is more common than we expect, we may need something
in core code instead.

        M.

diff --git a/drivers/pci/controller/pcie-mediatek.c 
b/drivers/pci/controller/pcie-mediatek.c
index cf4c18f0c25a..52758b546d40 100644
--- a/drivers/pci/controller/pcie-mediatek.c
+++ b/drivers/pci/controller/pcie-mediatek.c
@@ -151,6 +151,7 @@ struct mtk_pcie_port;
 struct mtk_pcie_soc {
        bool need_fix_class_id;
        bool need_fix_device_id;
+       bool no_msi;
        unsigned int device_id;
        struct pci_ops *ops;
        int (*startup)(struct mtk_pcie_port *port);
@@ -435,6 +436,9 @@ static int mtk_pcie_irq_domain_alloc(struct irq_domain 
*domain, unsigned int vir
        struct mtk_pcie_port *port = domain->host_data;
        unsigned long bit;
 
+       if (port->pcie->soc->no_msi)
+               return -ENOSPC;
+
        WARN_ON(nr_irqs != 1);
        mutex_lock(&port->lock);
 
@@ -966,11 +970,13 @@ static int mtk_pcie_parse_port(struct mtk_pcie *pcie,
        port->slot = slot;
        port->pcie = pcie;
 
-       if (pcie->soc->setup_irq) {
+       if (pcie->soc->setup_irq)
                err = pcie->soc->setup_irq(port, node);
-               if (err)
-                       return err;
-       }
+       else
+               err = mtk_pcie_allocate_msi_domains(port);
+
+       if (err)
+               return err;
 
        INIT_LIST_HEAD(&port->list);
        list_add_tail(&port->list, &pcie->ports);
@@ -1173,6 +1179,7 @@ static const struct dev_pm_ops mtk_pcie_pm_ops = {
 };
 
 static const struct mtk_pcie_soc mtk_pcie_soc_v1 = {
+       .no_msi = true,
        .ops = &mtk_pcie_ops,
        .startup = mtk_pcie_startup_port,
 };

-- 
Without deviation from the norm, progress is not possible.

Reply via email to