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Message-ID: <16d237b2-0052-447e-13cb-bc2f15848be4@synopsys.com>
Date: Tue, 24 Apr 2018 10:36:27 +0100
From: Gustavo Pimentel <gustavo.pimentel@...opsys.com>
To: Kishon Vijay Abraham I <kishon@...com>,
"bhelgaas@...gle.com" <bhelgaas@...gle.com>,
"lorenzo.pieralisi@....com" <lorenzo.pieralisi@....com>,
"Joao.Pinto@...opsys.com" <Joao.Pinto@...opsys.com>,
"jingoohan1@...il.com" <jingoohan1@...il.com>,
"adouglas@...ence.com" <adouglas@...ence.com>,
"niklas.cassel@...s.com" <niklas.cassel@...s.com>,
"jesper.nilsson@...s.com" <jesper.nilsson@...s.com>
Cc: "linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
"linux-doc@...r.kernel.org" <linux-doc@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [RFC 01/10] PCI: dwc: Add MSI-X callbacks handler
Hi Kishon,
On 24/04/2018 08:07, Kishon Vijay Abraham I wrote:
> Hi,
>
> On Monday 23 April 2018 03:06 PM, Gustavo Pimentel wrote:
>> Hi Kishon,
>>
>> On 16/04/2018 10:29, Kishon Vijay Abraham I wrote:
>>> Hi Gustavo,
>>>
>>> On Tuesday 10 April 2018 10:44 PM, Gustavo Pimentel wrote:
>>>> Changes the pcie_raise_irq function signature, namely the interrupt_num
>>>> variable type from u8 to u16 to accommodate the MSI-X maximum interrupts
>>>> of 2048.
>>>>
>>>> Implements a PCIe config space capability iterator function to search and
>>>> save the MSI and MSI-X pointers. With this method the code becomes more
>>>> generic and flexible.
>>>>
>>>> Implements MSI-X set/get functions for sysfs interface in order to change
>>>> the EP entries number.
>>>>
>>>> Implements EP MSI-X interface for triggering interruptions.
>>>>
>>>> Signed-off-by: Gustavo Pimentel <gustavo.pimentel@...opsys.com>
>>>> ---
>>>> drivers/pci/dwc/pci-dra7xx.c | 2 +-
>>>> drivers/pci/dwc/pcie-artpec6.c | 2 +-
>>>> drivers/pci/dwc/pcie-designware-ep.c | 145 ++++++++++++++++++++++++++++++++-
>>>> drivers/pci/dwc/pcie-designware-plat.c | 6 +-
>>>> drivers/pci/dwc/pcie-designware.h | 23 +++++-
>>>> 5 files changed, 173 insertions(+), 5 deletions(-)
>>>>
>>>> diff --git a/drivers/pci/dwc/pci-dra7xx.c b/drivers/pci/dwc/pci-dra7xx.c
>>>> index ed8558d..5265725 100644
>>>> --- a/drivers/pci/dwc/pci-dra7xx.c
>>>> +++ b/drivers/pci/dwc/pci-dra7xx.c
>>>> @@ -369,7 +369,7 @@ static void dra7xx_pcie_raise_msi_irq(struct dra7xx_pcie *dra7xx,
>>>> }
>>>>
>>>> static int dra7xx_pcie_raise_irq(struct dw_pcie_ep *ep, u8 func_no,
>>>> - enum pci_epc_irq_type type, u8 interrupt_num)
>>>> + enum pci_epc_irq_type type, u16 interrupt_num)
>>>> {
>>>> struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
>>>> struct dra7xx_pcie *dra7xx = to_dra7xx_pcie(pci);
>>>> diff --git a/drivers/pci/dwc/pcie-artpec6.c b/drivers/pci/dwc/pcie-artpec6.c
>>>> index e66cede..96dc259 100644
>>>> --- a/drivers/pci/dwc/pcie-artpec6.c
>>>> +++ b/drivers/pci/dwc/pcie-artpec6.c
>>>> @@ -428,7 +428,7 @@ static void artpec6_pcie_ep_init(struct dw_pcie_ep *ep)
>>>> }
>>>>
>>>> static int artpec6_pcie_raise_irq(struct dw_pcie_ep *ep, u8 func_no,
>>>> - enum pci_epc_irq_type type, u8 interrupt_num)
>>>> + enum pci_epc_irq_type type, u16 interrupt_num)
>>>> {
>>>> struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
>>>>
>>>> diff --git a/drivers/pci/dwc/pcie-designware-ep.c b/drivers/pci/dwc/pcie-designware-ep.c
>>>> index 15b22a6..874d4c2 100644
>>>> --- a/drivers/pci/dwc/pcie-designware-ep.c
>>>> +++ b/drivers/pci/dwc/pcie-designware-ep.c
>>>> @@ -40,6 +40,44 @@ void dw_pcie_ep_reset_bar(struct dw_pcie *pci, enum pci_barno bar)
>>>> __dw_pcie_ep_reset_bar(pci, bar, 0);
>>>> }
>>>>
>>>> +void dw_pcie_ep_find_cap_addr(struct dw_pcie_ep *ep)
>>>> +{
>>>
>>> This should be implemented in a generic way similar to pci_find_capability().
>>> It'll be useful when we try to implement other capabilities as well.
>>
>> Hum, what you suggest? Something implemented on the pci-epf-core?
>
> yeah, Initially thought it could be implemented as a helper function in
> pci-epc-core so that both designware and cadence can use it.
That would be nice, however I couldn't find out how to access the config space,
through the pci_epf or pci_epc structs.
So, I reworked the functions like this:
(on pcie-designware-ep.c)
u8 __dw_pcie_ep_find_next_cap(struct dw_pcie *pci, u8 cap_ptr,
u8 cap)
{
u8 cap_id, next_cap_ptr;
u16 reg;
reg = dw_pcie_readw_dbi(pci, cap_ptr);
next_cap_ptr = (reg & 0xff00) >> 8;
cap_id = (reg & 0x00ff);
if (!next_cap_ptr || cap_id > PCI_CAP_ID_MAX)
return 0;
if (cap_id == cap)
return cap_ptr;
return __dw_pcie_ep_find_next_cap(pci, next_cap_ptr, cap);
}
u8 dw_pcie_ep_find_capability(struct dw_pcie *pci, u8 cap)
{
u8 next_cap_ptr;
u16 reg;
reg = dw_pcie_readw_dbi(pci, PCI_CAPABILITY_LIST);
next_cap_ptr = (reg & 0x00ff);
if (!next_cap_ptr)
return 0;
return __dw_pcie_ep_find_next_cap(pci, next_cap_ptr, cap);
}
int dw_pcie_ep_init(struct dw_pcie_ep *ep)
{
[...]
ep->msi_cap = dw_pcie_ep_find_capability(pci, PCI_CAP_ID_MSI);
ep->msix_cap = dw_pcie_ep_find_capability(pci, PCI_CAP_ID_MSIX);
[...]
}
>
> But do we really have to find the address like this? since all designware IP's
> will have a particular capability at a fixed address offset, why not follow use
> existing mechanism in dw_pcie_ep_get_msi?
The capabilities are not fixed to a specific address offset by default they
assume those values, but they can be easily change at design stage.
>
> Or is it possible for a particular capability to have address offsets for
> different vendors? How is it for cadence?
Yes, it's possible to have different address offset for different vendors.
>
> Thanks
> Kishon
>
Thanks,
Gustavo
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