Re: [PATCH 1/4] PCI: dwc: Add new feature to skip core initialization
From: Vidya Sagar
Date: Wed Nov 27 2019 - 03:40:15 EST
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>
---
.../pci/controller/dwc/pcie-designware-ep.c | 72 +++++++++++--------
drivers/pci/controller/dwc/pcie-designware.h | 6 ++
include/linux/pci-epc.h | 1 +
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)
return 0;
}
-int dw_pcie_ep_init(struct dw_pcie_ep *ep)
+int dw_pcie_ep_init_complete(struct dw_pcie_ep *ep)
{
+ struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
+ unsigned int offset;
+ unsigned int nbars;
+ u8 hdr_type;
+ u32 reg;
int i;
+
+ hdr_type = dw_pcie_readb_dbi(pci, PCI_HEADER_TYPE);
+ if (hdr_type != PCI_HEADER_TYPE_NORMAL) {
+ dev_err(pci->dev,
+ "PCIe controller is not set to EP mode (hdr_type:0x%x)!\n",
+ hdr_type);
+ return -EIO;
+ }
+
+ ep->msi_cap = dw_pcie_find_capability(pci, PCI_CAP_ID_MSI);
+
+ ep->msix_cap = dw_pcie_find_capability(pci, PCI_CAP_ID_MSIX);
+
+ offset = dw_pcie_ep_find_ext_capability(pci, PCI_EXT_CAP_ID_REBAR);
+ if (offset) {
+ reg = dw_pcie_readl_dbi(pci, offset + PCI_REBAR_CTRL);
+ nbars = (reg & PCI_REBAR_CTRL_NBAR_MASK) >>
+ PCI_REBAR_CTRL_NBAR_SHIFT;
+
+ dw_pcie_dbi_ro_wr_en(pci);
+ for (i = 0; i < nbars; i++, offset += PCI_REBAR_CTRL)
+ dw_pcie_writel_dbi(pci, offset + PCI_REBAR_CAP, 0x0);
+ dw_pcie_dbi_ro_wr_dis(pci);
+ }
+
+ dw_pcie_setup(pci);
+
+ return 0;
+}
+
+int dw_pcie_ep_init(struct dw_pcie_ep *ep)
+{
int ret;
- u32 reg;
void *addr;
- u8 hdr_type;
- unsigned int nbars;
- unsigned int offset;
struct pci_epc *epc;
struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
struct device *dev = pci->dev;
struct device_node *np = dev->of_node;
+ const struct pci_epc_features *epc_features;
if (!pci->dbi_base || !pci->dbi_base2) {
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)
if (ep->ops->ep_init)
ep->ops->ep_init(ep);
- hdr_type = dw_pcie_readb_dbi(pci, PCI_HEADER_TYPE);
- if (hdr_type != PCI_HEADER_TYPE_NORMAL) {
- dev_err(pci->dev, "PCIe controller is not set to EP mode (hdr_type:0x%x)!\n",
- hdr_type);
- return -EIO;
- }
-
ret = of_property_read_u8(np, "max-functions", &epc->max_functions);
if (ret < 0)
epc->max_functions = 1;
@@ -587,23 +614,12 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
dev_err(dev, "Failed to reserve memory for MSI/MSI-X\n");
return -ENOMEM;
}
- ep->msi_cap = dw_pcie_find_capability(pci, PCI_CAP_ID_MSI);
- ep->msix_cap = dw_pcie_find_capability(pci, PCI_CAP_ID_MSIX);
-
- offset = dw_pcie_ep_find_ext_capability(pci, PCI_EXT_CAP_ID_REBAR);
- if (offset) {
- reg = dw_pcie_readl_dbi(pci, offset + PCI_REBAR_CTRL);
- nbars = (reg & PCI_REBAR_CTRL_NBAR_MASK) >>
- PCI_REBAR_CTRL_NBAR_SHIFT;
-
- dw_pcie_dbi_ro_wr_en(pci);
- for (i = 0; i < nbars; i++, offset += PCI_REBAR_CTRL)
- dw_pcie_writel_dbi(pci, offset + PCI_REBAR_CAP, 0x0);
- dw_pcie_dbi_ro_wr_dis(pci);
+ if (ep->ops->get_features) {
+ epc_features = ep->ops->get_features(ep);
+ if (epc_features->skip_core_init)
+ return 0;
}
- dw_pcie_setup(pci);
-
- return 0;
+ return dw_pcie_ep_init_complete(ep);
}
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)
#ifdef CONFIG_PCIE_DW_EP
void dw_pcie_ep_linkup(struct dw_pcie_ep *ep);
int dw_pcie_ep_init(struct dw_pcie_ep *ep);
+int dw_pcie_ep_init_complete(struct dw_pcie_ep *ep);
void dw_pcie_ep_exit(struct dw_pcie_ep *ep);
int dw_pcie_ep_raise_legacy_irq(struct dw_pcie_ep *ep, u8 func_no);
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)
return 0;
}
+static inline int dw_pcie_ep_init_complete(struct dw_pcie_ep *ep)
+{
+ return 0;
+}
+
static inline void dw_pcie_ep_exit(struct dw_pcie_ep *ep)
{
}
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 {
u8 bar_fixed_64bit;
u64 bar_fixed_size[PCI_STD_NUM_BARS];
size_t align;
+ bool 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.
Thanks,
Vidya Sagar
Thanks
Kishon