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From: Duc Dang <dhdang@apm.com>
Date: Thu, 9 Apr 2015 14:52:02 -0700
Message-ID: <CADaLND=3dj5LuHx9+OLmes8zDO_qFa1qV4bJz4Oy5Gw_OsgGXQ@mail.gmail.com>
Subject: Re: [PATCH v3 1/4] PCI: X-Gene: Add the APM X-Gene v1 PCIe MSI/MSIX
 termination driver
To: Bjorn Helgaas <bhelgaas@google.com>
Cc: Arnd Bergmann <arnd@arndb.de>, Grant Likely <grant.likely@linaro.org>,
        Liviu Dudau <Liviu.Dudau@arm.com>, Marc Zyngier <marc.zyngier@arm.com>,
        linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-kernel@vger.kernel.org, Tanmay Inamdar <tinamdar@apm.com>,
        Loc Ho <lho@apm.com>, Feng Kan <fkan@apm.com>
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On Thu, Apr 9, 2015 at 1:11 PM, Bjorn Helgaas <bhelgaas@google.com> wrote:
> On Thu, Apr 09, 2015 at 10:05:03AM -0700, Duc Dang wrote:
>> X-Gene v1 SoC supports total 2688 MSI/MSIX vectors coalesced into
>> 16 HW IRQ lines.
>>
>> Signed-off-by: Duc Dang <dhdang@apm.com>
>> Signed-off-by: Tanmay Inamdar <tinamdar@apm.com>
>> ...
>
>> --- /dev/null
>> +++ b/drivers/pci/host/pci-xgene-msi.c
>> @@ -0,0 +1,407 @@
>> ...
>
>> +static void xgene_irq_domain_free(struct irq_domain *domain,
>> +                               unsigned int virq, unsigned int nr_irqs)
>> +{
>> +     struct irq_data *d = irq_domain_get_irq_data(domain, virq);
>> +     struct xgene_msi *msi = irq_data_get_irq_chip_data(d);
>> +
>> +     mutex_lock(&msi->bitmap_lock);
>> +
>> +     if (!test_bit(d->hwirq, msi->bitmap))
>> +             pr_err("trying to free unused MSI#%lu\n", d->hwirq);
>
> I'll let Marc comment on the substance of this patch, but I'd sure like to
> see more information in this and the other pr_errs below.  The text "failed
> to create parent MSI domain" in the dmesg log is not enough.  Ideally it
> would identify the relevant host bridge.
>
Hi Bjorn,

X-Gene has single MSI block that serves 5 PCIe ports. so in this
implementation, 5 X-Gene PCIe host bridges share the same MSI domain.

I can add X-Gene 1 MSI driver name and device tree node name into
these messages, but the host bridge information is not available.

As I understand, in case of error, the upper layer MSI core and driver
code will check and report the error with additional device
information (bus number, function number, etc)?

Regards,
Duc Dang.

>> +     else
>> +             clear_bit(d->hwirq, msi->bitmap);
>> +
>> +     mutex_unlock(&msi->bitmap_lock);
>> +
>> +     irq_domain_free_irqs_parent(domain, virq, nr_irqs);
>> +}
>> +
>> +static const struct irq_domain_ops msi_domain_ops = {
>> +     .alloc  = xgene_irq_domain_alloc,
>> +     .free   = xgene_irq_domain_free,
>> +};
>> +
>> +static int xgene_allocate_domains(struct xgene_msi *msi)
>> +{
>> +     msi->domain = irq_domain_add_linear(NULL, msi->settings->nr_msi_vec,
>> +                                         &msi_domain_ops, msi);
>> +
>> +     if (!msi->domain) {
>> +             pr_err("failed to create parent MSI domain\n");
>> +             return -ENOMEM;
>> +     }
>> +
>> +     msi->mchip.of_node = msi->node;
>> +     msi->mchip.domain = pci_msi_create_irq_domain(msi->mchip.of_node,
>> +                                                   &xgene_msi_domain_info,
>> +                                                   msi->domain);
>> +
>> +     if (!msi->mchip.domain) {
>> +             pr_err("failed to create MSI domain\n");
>> +             irq_domain_remove(msi->domain);
>> +             return -ENOMEM;
>> +     }
>> +
>> +     return 0;
>> +}
>> +
>> +static void xgene_free_domains(struct xgene_msi *msi)
>> +{
>> +     if (msi->mchip.domain)
>> +             irq_domain_remove(msi->mchip.domain);
>> +     if (msi->domain)
>> +             irq_domain_remove(msi->domain);
>> +}
>> +
>> +static int xgene_msi_init_allocator(struct xgene_msi *xgene_msi)
>> +{
>> +     u32 msi_irq_count = xgene_msi->settings->nr_msi_vec;
>> +     u32 hw_irq_count = xgene_msi->settings->nr_hw_irqs;
>> +     int size = BITS_TO_LONGS(msi_irq_count) * sizeof(long);
>> +
>> +     xgene_msi->bitmap = kzalloc(size, GFP_KERNEL);
>> +     if (!xgene_msi->bitmap)
>> +             return -ENOMEM;
>> +
>> +     mutex_init(&xgene_msi->bitmap_lock);
>> +
>> +     xgene_msi->msi_virqs = kcalloc(hw_irq_count, sizeof(int), GFP_KERNEL);
>> +     if (!xgene_msi->msi_virqs)
>> +             return -ENOMEM;
>> +
>> +     return 0;
>> +}
>> +
>> +static irqreturn_t xgene_msi_isr(int irq, void *data)
>> +{
>> +     struct xgene_msi *xgene_msi = (struct xgene_msi *) data;
>> +     unsigned int virq;
>> +     int msir_index, msir_reg, msir_val, hw_irq;
>> +     u32 intr_index, grp_select, msi_grp, processed = 0;
>> +     u32 nr_hw_irqs, irqs_per_index, index_per_group;
>> +
>> +     msi_grp = irq - xgene_msi->msi_virqs[0];
>> +     if (msi_grp >= xgene_msi->settings->nr_hw_irqs) {
>> +             pr_err("invalid msi received\n");
>> +             return IRQ_NONE;
>> +     }
>
> Bjorn
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