Re: [PATCH 1/4] PCI: dwc: Add new feature to skip core initialization

[Kishon Vijay Abraham I]

Hi,

On 27/11/19 2:10 PM, Vidya Sagar wrote:
> On 11/27/2019 1:44 PM, Kishon Vijay Abraham I wrote:
>> Hi,
>>
>> On 13/11/19 2:38 PM, Vidya Sagar wrote:
>>> Add a new feature 'skip_core_init' that can be set by platform drivers
>>> of devices that do not have their core registers available until reference
>>> clock from host is available (Ex:- Tegra194) to indicate DesignWare
>>> endpoint mode sub-system to not perform core registers initialization.
>>> Existing dw_pcie_ep_init() is refactored and all the code that touches
>>> registers is extracted to form a new API dw_pcie_ep_init_complete() that
>>> can be called later by platform drivers setting 'skip_core_init' to '1'.
>>>
>>> Signed-off-by: Vidya Sagar <vidyas@xxxxxxxxxx>
>>> ---
>>> Â .../pci/controller/dwc/pcie-designware-ep.cÂÂ | 72 +++++++++++--------
>>>  drivers/pci/controller/dwc/pcie-designware.h | 6 ++
>>> Â include/linux/pci-epc.hÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |Â 1 +
>>> Â 3 files changed, 51 insertions(+), 28 deletions(-)
>>>
>>> diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c
>>> b/drivers/pci/controller/dwc/pcie-designware-ep.c
>>> index 3dd2e2697294..06f4379be8a3 100644
>>> --- a/drivers/pci/controller/dwc/pcie-designware-ep.c
>>> +++ b/drivers/pci/controller/dwc/pcie-designware-ep.c
>>> @@ -492,19 +492,53 @@ static unsigned int
>>> dw_pcie_ep_find_ext_capability(struct dw_pcie *pci, int cap)
>>> ÂÂÂÂÂ return 0;
>>> Â }
>>> Â -int dw_pcie_ep_init(struct dw_pcie_ep *ep)
>>> +int dw_pcie_ep_init_complete(struct dw_pcie_ep *ep)
>>> Â {
>>> +ÂÂÂ struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
>>> +ÂÂÂ unsigned int offset;
>>> +ÂÂÂ unsigned int nbars;
>>> +ÂÂÂ u8 hdr_type;
>>> +ÂÂÂ u32 reg;
>>> ÂÂÂÂÂ int i;
>>> +
>>> +ÂÂÂ hdr_type = dw_pcie_readb_dbi(pci, PCI_HEADER_TYPE);
>>> +ÂÂÂ if (hdr_type != PCI_HEADER_TYPE_NORMAL) {
>>> +ÂÂÂÂÂÂÂ dev_err(pci->dev,
>>> +ÂÂÂÂÂÂÂÂÂÂÂ "PCIe controller is not set to EP mode (hdr_type:0x%x)!\n",
>>> +ÂÂÂÂÂÂÂÂÂÂÂ hdr_type);
>>> +ÂÂÂÂÂÂÂ return -EIO;
>>> +ÂÂÂ }
>>> +
>>> +ÂÂÂ ep->msi_cap = dw_pcie_find_capability(pci, PCI_CAP_ID_MSI);
>>> +
>>> +ÂÂÂ ep->msix_cap = dw_pcie_find_capability(pci, PCI_CAP_ID_MSIX);
>>> +
>>> +ÂÂÂ offset = dw_pcie_ep_find_ext_capability(pci, PCI_EXT_CAP_ID_REBAR);
>>> +ÂÂÂ if (offset) {
>>> +ÂÂÂÂÂÂÂ reg = dw_pcie_readl_dbi(pci, offset + PCI_REBAR_CTRL);
>>> +ÂÂÂÂÂÂÂ nbars = (reg & PCI_REBAR_CTRL_NBAR_MASK) >>
>>> +ÂÂÂÂÂÂÂÂÂÂÂ PCI_REBAR_CTRL_NBAR_SHIFT;
>>> +
>>> +ÂÂÂÂÂÂÂ dw_pcie_dbi_ro_wr_en(pci);
>>> +ÂÂÂÂÂÂÂ for (i = 0; i < nbars; i++, offset += PCI_REBAR_CTRL)
>>> +ÂÂÂÂÂÂÂÂÂÂÂ dw_pcie_writel_dbi(pci, offset + PCI_REBAR_CAP, 0x0);
>>> +ÂÂÂÂÂÂÂ dw_pcie_dbi_ro_wr_dis(pci);
>>> +ÂÂÂ }
>>> +
>>> +ÂÂÂ dw_pcie_setup(pci);
>>> +
>>> +ÂÂÂ return 0;
>>> +}
>>> +
>>> +int dw_pcie_ep_init(struct dw_pcie_ep *ep)
>>> +{
>>> ÂÂÂÂÂ int ret;
>>> -ÂÂÂ u32 reg;
>>> ÂÂÂÂÂ void *addr;
>>> -ÂÂÂ u8 hdr_type;
>>> -ÂÂÂ unsigned int nbars;
>>> -ÂÂÂ unsigned int offset;
>>> ÂÂÂÂÂ struct pci_epc *epc;
>>> ÂÂÂÂÂ struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
>>> ÂÂÂÂÂ struct device *dev = pci->dev;
>>> ÂÂÂÂÂ struct device_node *np = dev->of_node;
>>> +ÂÂÂ const struct pci_epc_features *epc_features;
>>> Â ÂÂÂÂÂ if (!pci->dbi_base || !pci->dbi_base2) {
>>> ÂÂÂÂÂÂÂÂÂ dev_err(dev, "dbi_base/dbi_base2 is not populated\n");
>>> @@ -563,13 +597,6 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
>>> ÂÂÂÂÂ if (ep->ops->ep_init)
>>> ÂÂÂÂÂÂÂÂÂ ep->ops->ep_init(ep);
>>> Â -ÂÂÂ hdr_type = dw_pcie_readb_dbi(pci, PCI_HEADER_TYPE);
>>> -ÂÂÂ if (hdr_type != PCI_HEADER_TYPE_NORMAL) {
>>> -ÂÂÂÂÂÂÂ dev_err(pci->dev, "PCIe controller is not set to EP mode
>>> (hdr_type:0x%x)!\n",
>>> -ÂÂÂÂÂÂÂÂÂÂÂ hdr_type);
>>> -ÂÂÂÂÂÂÂ return -EIO;
>>> -ÂÂÂ }
>>> -
>>> ÂÂÂÂÂ ret = of_property_read_u8(np, "max-functions", &epc->max_functions);
>>> ÂÂÂÂÂ if (ret < 0)
>>> ÂÂÂÂÂÂÂÂÂ epc->max_functions = 1;
>>> @@ -587,23 +614,12 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
>>> ÂÂÂÂÂÂÂÂÂ dev_err(dev, "Failed to reserve memory for MSI/MSI-X\n");
>>> ÂÂÂÂÂÂÂÂÂ return -ENOMEM;
>>> ÂÂÂÂÂ }
>>> -ÂÂÂ ep->msi_cap = dw_pcie_find_capability(pci, PCI_CAP_ID_MSI);
>>> Â -ÂÂÂ ep->msix_cap = dw_pcie_find_capability(pci, PCI_CAP_ID_MSIX);
>>> -
>>> -ÂÂÂ offset = dw_pcie_ep_find_ext_capability(pci, PCI_EXT_CAP_ID_REBAR);
>>> -ÂÂÂ if (offset) {
>>> -ÂÂÂÂÂÂÂ reg = dw_pcie_readl_dbi(pci, offset + PCI_REBAR_CTRL);
>>> -ÂÂÂÂÂÂÂ nbars = (reg & PCI_REBAR_CTRL_NBAR_MASK) >>
>>> -ÂÂÂÂÂÂÂÂÂÂÂ PCI_REBAR_CTRL_NBAR_SHIFT;
>>> -
>>> -ÂÂÂÂÂÂÂ dw_pcie_dbi_ro_wr_en(pci);
>>> -ÂÂÂÂÂÂÂ for (i = 0; i < nbars; i++, offset += PCI_REBAR_CTRL)
>>> -ÂÂÂÂÂÂÂÂÂÂÂ dw_pcie_writel_dbi(pci, offset + PCI_REBAR_CAP, 0x0);
>>> -ÂÂÂÂÂÂÂ dw_pcie_dbi_ro_wr_dis(pci);
>>> +ÂÂÂ if (ep->ops->get_features) {
>>> +ÂÂÂÂÂÂÂ epc_features = ep->ops->get_features(ep);
>>> +ÂÂÂÂÂÂÂ if (epc_features->skip_core_init)
>>> +ÂÂÂÂÂÂÂÂÂÂÂ return 0;
>>> ÂÂÂÂÂ }
>>> Â -ÂÂÂ dw_pcie_setup(pci);
>>> -
>>> -ÂÂÂ return 0;
>>> +ÂÂÂ return dw_pcie_ep_init_complete(ep);
>>> Â }
>>> diff --git a/drivers/pci/controller/dwc/pcie-designware.h
>>> b/drivers/pci/controller/dwc/pcie-designware.h
>>> index 5accdd6bc388..340783e9032e 100644
>>> --- a/drivers/pci/controller/dwc/pcie-designware.h
>>> +++ b/drivers/pci/controller/dwc/pcie-designware.h
>>> @@ -399,6 +399,7 @@ static inline int dw_pcie_allocate_domains(struct
>>> pcie_port *pp)
>>> Â #ifdef CONFIG_PCIE_DW_EP
>>> Â void dw_pcie_ep_linkup(struct dw_pcie_ep *ep);
>>> Â int dw_pcie_ep_init(struct dw_pcie_ep *ep);
>>> +int dw_pcie_ep_init_complete(struct dw_pcie_ep *ep);
>>> Â void dw_pcie_ep_exit(struct dw_pcie_ep *ep);
>>> Â int dw_pcie_ep_raise_legacy_irq(struct dw_pcie_ep *ep, u8 func_no);
>>> Â int dw_pcie_ep_raise_msi_irq(struct dw_pcie_ep *ep, u8 func_no,
>>> @@ -416,6 +417,11 @@ static inline int dw_pcie_ep_init(struct dw_pcie_ep *ep)
>>> ÂÂÂÂÂ return 0;
>>> Â }
>>> Â +static inline int dw_pcie_ep_init_complete(struct dw_pcie_ep *ep)
>>> +{
>>> +ÂÂÂ return 0;
>>> +}
>>> +
>>> Â static inline void dw_pcie_ep_exit(struct dw_pcie_ep *ep)
>>> Â {
>>> Â }
>>> diff --git a/include/linux/pci-epc.h b/include/linux/pci-epc.h
>>> index 36644ccd32ac..241e6a6f39fb 100644
>>> --- a/include/linux/pci-epc.h
>>> +++ b/include/linux/pci-epc.h
>>> @@ -121,6 +121,7 @@ struct pci_epc_features {
>>> ÂÂÂÂÂ u8ÂÂÂ bar_fixed_64bit;
>>> ÂÂÂÂÂ u64ÂÂÂ bar_fixed_size[PCI_STD_NUM_BARS];
>>> ÂÂÂÂÂ size_tÂÂÂ align;
>>> +ÂÂÂ boolÂÂÂ skip_core_init;
>>
>> This looks more like a designware specific change. Why is it added to the core
>> pci_epc_features?
> Although the changes are done in DesignWare core (as Tegra194 uses DesignWare IP),
> core not being available for programming before REFCLK from host is available,
> seemed
> like a very generic case to me, so I added this as part of core features it self.

right, I think you can name the epc_feature as core_init_notifier instead of
skip_core_init (similar to linkup_notifier?) and add that as a first patch.
Then you can use the epc_features in epf_test and designware in subsequent patches.

Thanks
Kishon