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Groups > linux.kernel > #1281867 > unrolled thread
| Started by | Hauke Mehrtens <hauke@hauke-m.de> |
|---|---|
| First post | 2015-12-02 15:40 +0100 |
| Last post | 2015-12-02 18:20 +0100 |
| Articles | 2 — 2 participants |
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Re: [PATCH v4 4/5] PCI: iproc: Add iProc PCIe MSI support Hauke Mehrtens <hauke@hauke-m.de> - 2015-12-02 15:40 +0100
Re: [PATCH v4 4/5] PCI: iproc: Add iProc PCIe MSI support Ray Jui <rjui@broadcom.com> - 2015-12-02 18:20 +0100
| From | Hauke Mehrtens <hauke@hauke-m.de> |
|---|---|
| Date | 2015-12-02 15:40 +0100 |
| Subject | Re: [PATCH v4 4/5] PCI: iproc: Add iProc PCIe MSI support |
| Message-ID | <qBgJz-8no-3@gated-at.bofh.it> |
On 11/27/2015 06:37 PM, Ray Jui wrote:
> This patch adds PCIe MSI support for both PAXB and PAXC interfaces on
> all iProc based platforms
>
> The iProc PCIe MSI support deploys an event queue based implementation.
> Each event queue is serviced by a GIC interrupt and can support up to 64
> MSI vectors. Host memory is allocated for the event queues, and each event
> queue consists of 64 word-sized entries. MSI data is written to the
> lower 16-bit of each entry, whereas the upper 16-bit of the entry is
> reserved for the controller for internal processing
>
> Each event queue is tracked by a head pointer and tail pointer. Head
> pointer indicates the next entry in the event queue to be processed by
> the driver and is updated by the driver after processing is done.
> The controller uses the tail pointer as the next MSI data insertion
> point. The controller ensures MSI data is flushed to host memory before
> updating the tail pointer and then triggering the interrupt
>
> MSI IRQ affinity is supported by evenly distributing the interrupts to
> each CPU core. MSI vector is moved from one GIC interrupt to another in
> order to steer to the target CPU
>
> Therefore, the actual number of supported MSI vectors is:
>
> M * 64 / N
>
> where M denotes the number of GIC interrupts (event queues), and N
> denotes the number of CPU cores
>
> This iProc event queue based MSI support should not be used with newer
> platforms with integrated MSI support in the GIC (e.g., giv2m or
> gicv3-its)
>
> Signed-off-by: Ray Jui <rjui@broadcom.com>
> Reviewed-by: Anup Patel <anup.patel@broadcom.com>
> Reviewed-by: Vikram Prakash <vikramp@broadcom.com>
> Reviewed-by: Scott Branden <sbranden@broadcom.com>
> ---
> drivers/pci/host/Kconfig | 9 +
> drivers/pci/host/Makefile | 1 +
> drivers/pci/host/pcie-iproc-bcma.c | 1 +
> drivers/pci/host/pcie-iproc-msi.c | 675 +++++++++++++++++++++++++++++++++
> drivers/pci/host/pcie-iproc-platform.c | 1 +
> drivers/pci/host/pcie-iproc.c | 26 ++
> drivers/pci/host/pcie-iproc.h | 23 +-
> 7 files changed, 734 insertions(+), 2 deletions(-)
> create mode 100644 drivers/pci/host/pcie-iproc-msi.c
>
.....
>
> int iproc_pcie_setup(struct iproc_pcie *pcie, struct list_head *res);
> int iproc_pcie_remove(struct iproc_pcie *pcie);
>
> +#ifdef CONFIG_PCI_MSI
> +int iproc_msi_init(struct iproc_pcie *pcie, struct device_node *node);
> +void iproc_msi_exit(struct iproc_pcie *pcie);
> +#else
> +static inline int iproc_msi_init(struct iproc_pcie *pcie,
> + struct device_node *node)
> +{
> + return -ENODEV;
> +}
> +static void iproc_msi_exit(struct iproc_pcie *pcie)
Please use static inline here.
> +{
> +}
> +#endif
> +
> #endif /* _PCIE_IPROC_H */
>
Hauke
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| From | Ray Jui <rjui@broadcom.com> |
|---|---|
| Date | 2015-12-02 18:20 +0100 |
| Message-ID | <qBjet-1JE-73@gated-at.bofh.it> |
| In reply to | #1281867 |
On 12/2/2015 6:30 AM, Hauke Mehrtens wrote:
> On 11/27/2015 06:37 PM, Ray Jui wrote:
>> This patch adds PCIe MSI support for both PAXB and PAXC interfaces on
>> all iProc based platforms
>>
>> The iProc PCIe MSI support deploys an event queue based implementation.
>> Each event queue is serviced by a GIC interrupt and can support up to 64
>> MSI vectors. Host memory is allocated for the event queues, and each event
>> queue consists of 64 word-sized entries. MSI data is written to the
>> lower 16-bit of each entry, whereas the upper 16-bit of the entry is
>> reserved for the controller for internal processing
>>
>> Each event queue is tracked by a head pointer and tail pointer. Head
>> pointer indicates the next entry in the event queue to be processed by
>> the driver and is updated by the driver after processing is done.
>> The controller uses the tail pointer as the next MSI data insertion
>> point. The controller ensures MSI data is flushed to host memory before
>> updating the tail pointer and then triggering the interrupt
>>
>> MSI IRQ affinity is supported by evenly distributing the interrupts to
>> each CPU core. MSI vector is moved from one GIC interrupt to another in
>> order to steer to the target CPU
>>
>> Therefore, the actual number of supported MSI vectors is:
>>
>> M * 64 / N
>>
>> where M denotes the number of GIC interrupts (event queues), and N
>> denotes the number of CPU cores
>>
>> This iProc event queue based MSI support should not be used with newer
>> platforms with integrated MSI support in the GIC (e.g., giv2m or
>> gicv3-its)
>>
>> Signed-off-by: Ray Jui <rjui@broadcom.com>
>> Reviewed-by: Anup Patel <anup.patel@broadcom.com>
>> Reviewed-by: Vikram Prakash <vikramp@broadcom.com>
>> Reviewed-by: Scott Branden <sbranden@broadcom.com>
>> ---
>> drivers/pci/host/Kconfig | 9 +
>> drivers/pci/host/Makefile | 1 +
>> drivers/pci/host/pcie-iproc-bcma.c | 1 +
>> drivers/pci/host/pcie-iproc-msi.c | 675 +++++++++++++++++++++++++++++++++
>> drivers/pci/host/pcie-iproc-platform.c | 1 +
>> drivers/pci/host/pcie-iproc.c | 26 ++
>> drivers/pci/host/pcie-iproc.h | 23 +-
>> 7 files changed, 734 insertions(+), 2 deletions(-)
>> create mode 100644 drivers/pci/host/pcie-iproc-msi.c
>>
>
> .....
>>
>> int iproc_pcie_setup(struct iproc_pcie *pcie, struct list_head *res);
>> int iproc_pcie_remove(struct iproc_pcie *pcie);
>>
>> +#ifdef CONFIG_PCI_MSI
>> +int iproc_msi_init(struct iproc_pcie *pcie, struct device_node *node);
>> +void iproc_msi_exit(struct iproc_pcie *pcie);
>> +#else
>> +static inline int iproc_msi_init(struct iproc_pcie *pcie,
>> + struct device_node *node)
>> +{
>> + return -ENODEV;
>> +}
>> +static void iproc_msi_exit(struct iproc_pcie *pcie)
>
> Please use static inline here.
>
Right. Will fix. Thanks!
>> +{
>> +}
>> +#endif
>> +
>> #endif /* _PCIE_IPROC_H */
>>
>
> Hauke
>
Ray
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