2022-10-13 18:31:57

by Vidya Sagar

[permalink] [raw]
Subject: [PATCH V5 1/3] PCI: designware-ep: Fix DBI access before core init

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 <[email protected]>
---
V5:
* Changed dw_pcie_ep_init_complete() to dw_pcie_ep_init_late()
* Skipped memory allocation if done already. This is to avoid freeing and then
allocating again during PERST# toggles from the host.

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 | 125 +++++++++++-------
drivers/pci/controller/dwc/pcie-designware.h | 10 +-
2 files changed, 80 insertions(+), 55 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c
index 83ddb190292e..f300ea2f7bf7 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_late(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 +655,51 @@ int dw_pcie_ep_init_complete(struct dw_pcie_ep *ep)
return -EIO;
}

+ dw_pcie_version_detect(pci);
+
+ dw_pcie_iatu_detect(pci);
+
+ if (!ep->ib_window_map) {
+ ep->ib_window_map = devm_bitmap_zalloc(dev, pci->num_ib_windows,
+ GFP_KERNEL);
+ if (!ep->ib_window_map)
+ return -ENOMEM;
+ }
+
+ if (!ep->ob_window_map) {
+ ep->ob_window_map = devm_bitmap_zalloc(dev, pci->num_ob_windows,
+ GFP_KERNEL);
+ if (!ep->ob_window_map)
+ return -ENOMEM;
+ }
+
+ if (!ep->outbound_addr) {
+ 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 = dw_pcie_ep_get_func_from_ep(ep, func_no);
+ if (ep_func)
+ continue;
+
+ 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 +718,28 @@ 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_late(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 +747,6 @@ 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 +775,6 @@ 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 +791,6 @@ 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);

@@ -793,7 +815,14 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
return 0;
}

- ret = dw_pcie_ep_init_complete(ep);
+ /*
+ * 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_late(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 45fcdfc8c035..7252513956b7 100644
--- a/drivers/pci/controller/dwc/pcie-designware.h
+++ b/drivers/pci/controller/dwc/pcie-designware.h
@@ -253,6 +253,7 @@ 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


2022-10-15 22:05:56

by Jingoo Han

[permalink] [raw]
Subject: Re: [PATCH V5 1/3] PCI: designware-ep: Fix DBI access before core init

On Thu, Oct 13, 2022 Vidya Sagar <[email protected]> wrote:
>
> 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 <[email protected]>
> ---
> V5:
> * Changed dw_pcie_ep_init_complete() to dw_pcie_ep_init_late()
> * Skipped memory allocation if done already. This is to avoid freeing and then
> allocating again during PERST# toggles from the host.
>
> 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 | 125 +++++++++++-------
> drivers/pci/controller/dwc/pcie-designware.h | 10 +-
> 2 files changed, 80 insertions(+), 55 deletions(-)

Acked-by: Jingoo Han <[email protected]>

The function name 'dw_pcie_ep_init_late' looks clear to me. Also,
commit messages
and comments are understandable. So, I am ok with the patches, but I also think
that we need to wait for Manivannan's Tested-by on qcom platforms.

Best regards,
Jingoo Han

>
> diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c
> index 83ddb190292e..f300ea2f7bf7 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_late(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 +655,51 @@ int dw_pcie_ep_init_complete(struct dw_pcie_ep *ep)
> return -EIO;
> }
>
> + dw_pcie_version_detect(pci);
> +
> + dw_pcie_iatu_detect(pci);
> +
> + if (!ep->ib_window_map) {
> + ep->ib_window_map = devm_bitmap_zalloc(dev, pci->num_ib_windows,
> + GFP_KERNEL);
> + if (!ep->ib_window_map)
> + return -ENOMEM;
> + }
> +
> + if (!ep->ob_window_map) {
> + ep->ob_window_map = devm_bitmap_zalloc(dev, pci->num_ob_windows,
> + GFP_KERNEL);
> + if (!ep->ob_window_map)
> + return -ENOMEM;
> + }
> +
> + if (!ep->outbound_addr) {
> + 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 = dw_pcie_ep_get_func_from_ep(ep, func_no);
> + if (ep_func)
> + continue;
> +
> + 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 +718,28 @@ 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_late(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 +747,6 @@ 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 +775,6 @@ 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 +791,6 @@ 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);
>
> @@ -793,7 +815,14 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
> return 0;
> }
>
> - ret = dw_pcie_ep_init_complete(ep);
> + /*
> + * 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_late(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 45fcdfc8c035..7252513956b7 100644
> --- a/drivers/pci/controller/dwc/pcie-designware.h
> +++ b/drivers/pci/controller/dwc/pcie-designware.h
> @@ -253,6 +253,7 @@ 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
>

2022-10-26 05:24:09

by Manivannan Sadhasivam

[permalink] [raw]
Subject: Re: [PATCH V5 1/3] PCI: designware-ep: Fix DBI access before core init

On Thu, Oct 13, 2022 at 11:27:10PM +0530, Vidya Sagar wrote:
> 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

dw_pcie_ep_init_complete() got renamed to dw_pcie_ep_init_late()

> 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 <[email protected]>
> ---
> V5:
> * Changed dw_pcie_ep_init_complete() to dw_pcie_ep_init_late()
> * Skipped memory allocation if done already. This is to avoid freeing and then
> allocating again during PERST# toggles from the host.
>
> 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 | 125 +++++++++++-------
> drivers/pci/controller/dwc/pcie-designware.h | 10 +-
> 2 files changed, 80 insertions(+), 55 deletions(-)
>
> diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c
> index 83ddb190292e..f300ea2f7bf7 100644
> --- a/drivers/pci/controller/dwc/pcie-designware-ep.c
> +++ b/drivers/pci/controller/dwc/pcie-designware-ep.c

[...]

> +int dw_pcie_ep_init_notify(struct dw_pcie_ep *ep)
> +{
> + struct pci_epc *epc = ep->epc;
> + int ret;
> +
> + ret = dw_pcie_ep_init_late(ep);
> + if (ret)
> + return ret;
> +
> + if (ep->ops->ep_init_late)
> + ep->ops->ep_init_late(ep);

I think you introduced this callback for the sake of Qcom driver I believe.
But it is not really required. I'll share more comments in patch 2/3.

Thanks,
Mani

> +
> + 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 +747,6 @@ 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 +775,6 @@ 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 +791,6 @@ 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);
>
> @@ -793,7 +815,14 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
> return 0;
> }
>
> - ret = dw_pcie_ep_init_complete(ep);
> + /*
> + * 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_late(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 45fcdfc8c035..7252513956b7 100644
> --- a/drivers/pci/controller/dwc/pcie-designware.h
> +++ b/drivers/pci/controller/dwc/pcie-designware.h
> @@ -253,6 +253,7 @@ 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
>

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