[PATCH V4 1/3] PCI: designware-ep: Fix DBI access before core init
From: Vidya Sagar
Date: Mon Sep 19 2022 - 14:34:24 EST
Platforms that cannot support their core initialization without the
reference clock from the host, implement the feature 'core_init_notifier'
to indicate the DesignWare sub-system about when their core is getting
initialized. Any accesses to the core (Ex:- DBI) would the core being
ready result in system hang in such systems (Ex:- tegra194).
This patch moves any access to the core to dw_pcie_ep_init_complete() API
which is effectively called only after the core initialization.
It also introduces .ep_init_late() ops hook to be used for any post init
work that platform drivers may have to do.
Signed-off-by: Vidya Sagar <vidyas@xxxxxxxxxx>
---
V4:
* Addressed review comments from Bjorn and Manivannan
* Moved dw_pcie_ep_init_complete() inside dw_pcie_ep_init_notify()
* Added .ep_init_late() ops to perform late init tasks
.../pci/controller/dwc/pcie-designware-ep.c | 112 ++++++++++--------
drivers/pci/controller/dwc/pcie-designware.h | 10 +-
2 files changed, 68 insertions(+), 54 deletions(-)
diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c
index 83ddb190292e..095fb0291ec9 100644
--- a/drivers/pci/controller/dwc/pcie-designware-ep.c
+++ b/drivers/pci/controller/dwc/pcie-designware-ep.c
@@ -23,14 +23,6 @@ void dw_pcie_ep_linkup(struct dw_pcie_ep *ep)
}
EXPORT_SYMBOL_GPL(dw_pcie_ep_linkup);
-void dw_pcie_ep_init_notify(struct dw_pcie_ep *ep)
-{
- struct pci_epc *epc = ep->epc;
-
- pci_epc_init_notify(epc);
-}
-EXPORT_SYMBOL_GPL(dw_pcie_ep_init_notify);
-
struct dw_pcie_ep_func *
dw_pcie_ep_get_func_from_ep(struct dw_pcie_ep *ep, u8 func_no)
{
@@ -640,12 +632,17 @@ static unsigned int dw_pcie_ep_find_ext_capability(struct dw_pcie *pci, int cap)
return 0;
}
-int dw_pcie_ep_init_complete(struct dw_pcie_ep *ep)
+static int dw_pcie_ep_init_complete(struct dw_pcie_ep *ep)
{
struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
+ struct dw_pcie_ep_func *ep_func;
+ struct device *dev = pci->dev;
+ struct pci_epc *epc = ep->epc;
unsigned int offset;
unsigned int nbars;
u8 hdr_type;
+ u8 func_no;
+ void *addr;
u32 reg;
int i;
@@ -658,6 +655,40 @@ int dw_pcie_ep_init_complete(struct dw_pcie_ep *ep)
return -EIO;
}
+ dw_pcie_version_detect(pci);
+
+ dw_pcie_iatu_detect(pci);
+
+ ep->ib_window_map = devm_bitmap_zalloc(dev, pci->num_ib_windows,
+ GFP_KERNEL);
+ if (!ep->ib_window_map)
+ return -ENOMEM;
+
+ ep->ob_window_map = devm_bitmap_zalloc(dev, pci->num_ob_windows,
+ GFP_KERNEL);
+ if (!ep->ob_window_map)
+ return -ENOMEM;
+
+ addr = devm_kcalloc(dev, pci->num_ob_windows, sizeof(phys_addr_t),
+ GFP_KERNEL);
+ if (!addr)
+ return -ENOMEM;
+ ep->outbound_addr = addr;
+
+ for (func_no = 0; func_no < epc->max_functions; func_no++) {
+ ep_func = devm_kzalloc(dev, sizeof(*ep_func), GFP_KERNEL);
+ if (!ep_func)
+ return -ENOMEM;
+
+ ep_func->func_no = func_no;
+ ep_func->msi_cap = dw_pcie_ep_find_capability(ep, func_no,
+ PCI_CAP_ID_MSI);
+ ep_func->msix_cap = dw_pcie_ep_find_capability(ep, func_no,
+ PCI_CAP_ID_MSIX);
+
+ list_add_tail(&ep_func->list, &ep->func_list);
+ }
+
offset = dw_pcie_ep_find_ext_capability(pci, PCI_EXT_CAP_ID_REBAR);
dw_pcie_dbi_ro_wr_en(pci);
@@ -676,13 +707,28 @@ int dw_pcie_ep_init_complete(struct dw_pcie_ep *ep)
return 0;
}
-EXPORT_SYMBOL_GPL(dw_pcie_ep_init_complete);
+
+int dw_pcie_ep_init_notify(struct dw_pcie_ep *ep)
+{
+ struct pci_epc *epc = ep->epc;
+ int ret;
+
+ ret = dw_pcie_ep_init_complete(ep);
+ if (ret)
+ return ret;
+
+ if (ep->ops->ep_init_late)
+ ep->ops->ep_init_late(ep);
+
+ pci_epc_init_notify(epc);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(dw_pcie_ep_init_notify);
int dw_pcie_ep_init(struct dw_pcie_ep *ep)
{
int ret;
- void *addr;
- u8 func_no;
struct resource *res;
struct pci_epc *epc;
struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
@@ -690,7 +736,6 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
struct platform_device *pdev = to_platform_device(dev);
struct device_node *np = dev->of_node;
const struct pci_epc_features *epc_features;
- struct dw_pcie_ep_func *ep_func;
INIT_LIST_HEAD(&ep->func_list);
@@ -719,26 +764,6 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
ep->phys_base = res->start;
ep->addr_size = resource_size(res);
- dw_pcie_version_detect(pci);
-
- dw_pcie_iatu_detect(pci);
-
- ep->ib_window_map = devm_bitmap_zalloc(dev, pci->num_ib_windows,
- GFP_KERNEL);
- if (!ep->ib_window_map)
- return -ENOMEM;
-
- ep->ob_window_map = devm_bitmap_zalloc(dev, pci->num_ob_windows,
- GFP_KERNEL);
- if (!ep->ob_window_map)
- return -ENOMEM;
-
- addr = devm_kcalloc(dev, pci->num_ob_windows, sizeof(phys_addr_t),
- GFP_KERNEL);
- if (!addr)
- return -ENOMEM;
- ep->outbound_addr = addr;
-
if (pci->link_gen < 1)
pci->link_gen = of_pci_get_max_link_speed(np);
@@ -755,20 +780,6 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
if (ret < 0)
epc->max_functions = 1;
- for (func_no = 0; func_no < epc->max_functions; func_no++) {
- ep_func = devm_kzalloc(dev, sizeof(*ep_func), GFP_KERNEL);
- if (!ep_func)
- return -ENOMEM;
-
- ep_func->func_no = func_no;
- ep_func->msi_cap = dw_pcie_ep_find_capability(ep, func_no,
- PCI_CAP_ID_MSI);
- ep_func->msix_cap = dw_pcie_ep_find_capability(ep, func_no,
- PCI_CAP_ID_MSIX);
-
- list_add_tail(&ep_func->list, &ep->func_list);
- }
-
if (ep->ops->ep_init)
ep->ops->ep_init(ep);
@@ -793,6 +804,13 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
return 0;
}
+ /*
+ * NOTE:- Avoid accessing the hardware (Ex:- DBI space) before this
+ * step as platforms that implement 'core_init_notifier' feature may
+ * not have the hardware ready (i.e. core initialized) for access
+ * (Ex: tegra194). Any hardware access on such platforms result
+ * in system hard hang.
+ */
ret = dw_pcie_ep_init_complete(ep);
if (ret)
goto err_free_epc_mem;
diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
index 09b887093a84..7222717afa33 100644
--- a/drivers/pci/controller/dwc/pcie-designware.h
+++ b/drivers/pci/controller/dwc/pcie-designware.h
@@ -254,6 +254,7 @@ struct dw_pcie_rp {
struct dw_pcie_ep_ops {
void (*ep_init)(struct dw_pcie_ep *ep);
+ void (*ep_init_late)(struct dw_pcie_ep *ep);
int (*raise_irq)(struct dw_pcie_ep *ep, u8 func_no,
enum pci_epc_irq_type type, u16 interrupt_num);
const struct pci_epc_features* (*get_features)(struct dw_pcie_ep *ep);
@@ -467,8 +468,7 @@ static inline void __iomem *dw_pcie_own_conf_map_bus(struct pci_bus *bus,
#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_init_notify(struct dw_pcie_ep *ep);
+int dw_pcie_ep_init_notify(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,
@@ -490,15 +490,11 @@ 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)
+static inline int dw_pcie_ep_init_notify(struct dw_pcie_ep *ep)
{
return 0;
}
-static inline void dw_pcie_ep_init_notify(struct dw_pcie_ep *ep)
-{
-}
-
static inline void dw_pcie_ep_exit(struct dw_pcie_ep *ep)
{
}
--
2.17.1