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SubjectRe: [RFC 03/10] PCI: endpoint: Add MSI-X interfaces
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Hi Kishon,

On 17/04/2018 11:24, Kishon Vijay Abraham I wrote:
> Hi,
>
> On Tuesday 10 April 2018 10:44 PM, Gustavo Pimentel wrote:
>> Implements the generic method for calling the get/set callbacks.
>>
>> Adds the PCI_EPC_IRQ_MSIX type.
>>
>> Adds the MSI-X callbacks signatures to the ops structure.
>>
>> Adds sysfs interface for altering the number of MSI-X entries.
>>
>> Signed-off-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
>> ---
>> drivers/pci/endpoint/pci-ep-cfs.c | 24 ++++++++++++++++
>> drivers/pci/endpoint/pci-epc-core.c | 57 +++++++++++++++++++++++++++++++++++++
>> include/linux/pci-epc.h | 11 ++++++-
>> include/linux/pci-epf.h | 1 +
>> 4 files changed, 92 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/pci/endpoint/pci-ep-cfs.c b/drivers/pci/endpoint/pci-ep-cfs.c
>> index 018ea34..d1288a0 100644
>> --- a/drivers/pci/endpoint/pci-ep-cfs.c
>> +++ b/drivers/pci/endpoint/pci-ep-cfs.c
>> @@ -286,6 +286,28 @@ static ssize_t pci_epf_msi_interrupts_show(struct config_item *item,
>> to_pci_epf_group(item)->epf->msi_interrupts);
>> }
>>
>> +static ssize_t pci_epf_msix_interrupts_store(struct config_item *item,
>> + const char *page, size_t len)
>> +{
>> + u16 val;
>> + int ret;
>> +
>> + ret = kstrtou16(page, 0, &val);
>> + if (ret)
>> + return ret;
>> +
>> + to_pci_epf_group(item)->epf->msix_interrupts = val;
>> +
>> + return len;
>> +}
>> +
>> +static ssize_t pci_epf_msix_interrupts_show(struct config_item *item,
>> + char *page)
>> +{
>> + return sprintf(page, "%d\n",
>> + to_pci_epf_group(item)->epf->msix_interrupts);
>> +}
>> +
>> PCI_EPF_HEADER_R(vendorid)
>> PCI_EPF_HEADER_W_u16(vendorid)
>>
>> @@ -327,6 +349,7 @@ CONFIGFS_ATTR(pci_epf_, subsys_vendor_id);
>> CONFIGFS_ATTR(pci_epf_, subsys_id);
>> CONFIGFS_ATTR(pci_epf_, interrupt_pin);
>> CONFIGFS_ATTR(pci_epf_, msi_interrupts);
>> +CONFIGFS_ATTR(pci_epf_, msix_interrupts);
>>
>> static struct configfs_attribute *pci_epf_attrs[] = {
>> &pci_epf_attr_vendorid,
>> @@ -340,6 +363,7 @@ static struct configfs_attribute *pci_epf_attrs[] = {
>> &pci_epf_attr_subsys_id,
>> &pci_epf_attr_interrupt_pin,
>> &pci_epf_attr_msi_interrupts,
>> + &pci_epf_attr_msix_interrupts,
>> NULL,
>> };
>>
>> diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
>> index b0ee427..294a383 100644
>> --- a/drivers/pci/endpoint/pci-epc-core.c
>> +++ b/drivers/pci/endpoint/pci-epc-core.c
>> @@ -218,6 +218,63 @@ int pci_epc_set_msi(struct pci_epc *epc, u8 func_no, u8 interrupts)
>> EXPORT_SYMBOL_GPL(pci_epc_set_msi);
>>
>> /**
>> + * pci_epc_get_msix() - get the number of MSI-X interrupt numbers allocated
>> + * @epc: the EPC device to which MSI-X interrupts was requested
>> + * @func_no: the endpoint function number in the EPC device
>> + *
>> + * Invoke to get the number of MSI-X interrupts allocated by the RC
>> + */
>> +int pci_epc_get_msix(struct pci_epc *epc, u8 func_no)
>> +{
>> + int interrupt;
>> + unsigned long flags;
>> +
>> + if (IS_ERR_OR_NULL(epc) || func_no >= epc->max_functions)
>> + return 0;
>> +
>> + if (!epc->ops->get_msix)
>> + return 0;
>> +
>> + spin_lock_irqsave(&epc->lock, flags);
>> + interrupt = epc->ops->get_msix(epc, func_no);
>> + spin_unlock_irqrestore(&epc->lock, flags);
>> +
>> + if (interrupt < 0)
>> + return 0;
>> +
>> + return interrupt++;
>
> return interrupt + 1?

I'll change it.

>> +}
>> +EXPORT_SYMBOL_GPL(pci_epc_get_msix);
>> +
>> +/**
>> + * pci_epc_set_msix() - set the number of MSI-X interrupt numbers required
>> + * @epc: the EPC device on which MSI-X has to be configured
>> + * @func_no: the endpoint function number in the EPC device
>> + * @interrupts: number of MSI-X interrupts required by the EPF
>> + *
>> + * Invoke to set the required number of MSI-X interrupts.
>> + */
>> +int pci_epc_set_msix(struct pci_epc *epc, u8 func_no, u16 interrupts)
>> +{
>> + int ret;
>> + unsigned long flags;
>> +
>> + if (IS_ERR_OR_NULL(epc) || func_no >= epc->max_functions ||
>> + interrupts < 1 || interrupts > 2048)
>> + return -EINVAL;
>> +
>> + if (!epc->ops->set_msix)
>> + return 0;
>> +
>> + spin_lock_irqsave(&epc->lock, flags);
>> + ret = epc->ops->set_msix(epc, func_no, interrupts - 1);
>> + spin_unlock_irqrestore(&epc->lock, flags);
>> +
>> + return ret;
>> +}
>> +EXPORT_SYMBOL_GPL(pci_epc_set_msix);
>> +
>> +/**
>> * pci_epc_unmap_addr() - unmap CPU address from PCI address
>> * @epc: the EPC device on which address is allocated
>> * @func_no: the endpoint function number in the EPC device
>> diff --git a/include/linux/pci-epc.h b/include/linux/pci-epc.h
>> index af657ca..32e8961 100644
>> --- a/include/linux/pci-epc.h
>> +++ b/include/linux/pci-epc.h
>> @@ -17,6 +17,7 @@ enum pci_epc_irq_type {
>> PCI_EPC_IRQ_UNKNOWN,
>> PCI_EPC_IRQ_LEGACY,
>> PCI_EPC_IRQ_MSI,
>> + PCI_EPC_IRQ_MSIX,
>> };
>>
>> /**
>> @@ -30,6 +31,10 @@ enum pci_epc_irq_type {
>> * capability register
>> * @get_msi: ops to get the number of MSI interrupts allocated by the RC from
>> * the MSI capability register
>> + * @set_msix: ops to set the requested number of MSI-X interrupts in the
>> + * MSI-X capability register
>> + * @get_msix: ops to get the number of MSI-X interrupts allocated by the RC
>> + * from the MSI-X capability register
>> * @raise_irq: ops to raise a legacy or MSI interrupt
>> * @start: ops to start the PCI link
>> * @stop: ops to stop the PCI link
>> @@ -48,8 +53,10 @@ struct pci_epc_ops {
>> phys_addr_t addr);
>> int (*set_msi)(struct pci_epc *epc, u8 func_no, u8 interrupts);
>> int (*get_msi)(struct pci_epc *epc, u8 func_no);
>> + int (*set_msix)(struct pci_epc *epc, u8 func_no, u16 interrupts);
>> + int (*get_msix)(struct pci_epc *epc, u8 func_no);
>
> The 1st patch in the series is already using get_msix, set_msix. This patch
> should precede the 1st patch.

Yes, you're right.

>
> Thanks
> Kishon
>

Regards,
Gustavo

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