Re: [RFC PATCH kernel] powerpc/pci: Get rid of unused @parent pointer in pci_controller
On 06/11/17 14:33, Benjamin Herrenschmidt wrote:
> On Mon, 2017-11-06 at 14:24 +1100, Alexey Kardashevskiy wrote:
>> The @parent pointer is supposed to point to a device which represents
>> a PCI controller, however it is never set to anything and remains NULL;
>> it is also quite common to pass NULL to pci_create_root_bus().
>>
>> Signed-off-by: Alexey Kardashevskiy
>> ---
>
> It's used for anything using of_pci_phb_probe() such as Cell.
ah, ok, thanks.
>
>
>>
>> This @parent is NULL for every PHB in garrison machines, for example.
>> Where would this pointer be really used?
>>
>> I wonder how does setting it make any difference in sysfs for CXL vphb?
>>
>> In general, I'd think that @parent makes sense and every PHB
>> has a parent device struct like any other device and the platform
>> code binds a correct device driver to a PHB and we can avoid
>> having PNV_PHB_IODA2&co switches but for some reason PHBs are
>> hardcoded in the platform code.
>>
>> ---
>> arch/powerpc/include/asm/pci-bridge.h | 1 -
>> arch/powerpc/kernel/pci-common.c | 2 +-
>> drivers/misc/cxl/vphb.c | 3 ---
>> 3 files changed, 1 insertion(+), 5 deletions(-)
>>
>> diff --git a/arch/powerpc/include/asm/pci-bridge.h
>> b/arch/powerpc/include/asm/pci-bridge.h
>> index 752718a2949d..ad88ddeaa6b7 100644
>> --- a/arch/powerpc/include/asm/pci-bridge.h
>> +++ b/arch/powerpc/include/asm/pci-bridge.h
>> @@ -60,7 +60,6 @@ struct pci_controller {
>> #endif
>> struct device_node *dn;
>> struct list_head list_node;
>> -struct device *parent;
>>
>> int first_busno;
>> int last_busno;
>> diff --git a/arch/powerpc/kernel/pci-common.c
>> b/arch/powerpc/kernel/pci-common.c
>> index 02831a396419..597576777c34 100644
>> --- a/arch/powerpc/kernel/pci-common.c
>> +++ b/arch/powerpc/kernel/pci-common.c
>> @@ -1681,7 +1681,7 @@ void pcibios_scan_phb(struct pci_controller *hose)
>> pci_add_resource(&resources, &hose->busn);
>>
>> /* Create an empty bus for the toplevel */
>> -bus = pci_create_root_bus(hose->parent, hose->first_busno,
>> +bus = pci_create_root_bus(NULL, hose->first_busno,
>>hose->ops, hose, &resources);
>> if (bus == NULL) {
>> pr_err("Failed to create bus for PCI domain %04x\n",
>> diff --git a/drivers/misc/cxl/vphb.c b/drivers/misc/cxl/vphb.c
>> index 512a4897dbf6..ae3fe1563812 100644
>> --- a/drivers/misc/cxl/vphb.c
>> +++ b/drivers/misc/cxl/vphb.c
>> @@ -232,9 +232,6 @@ int cxl_pci_vphb_add(struct cxl_afu *afu)
>> if (!phb)
>> return -ENODEV;
>>
>> -/* Setup parent in sysfs */
>> -phb->parent = parent;
>> -
>> /* Setup the PHB using arch provided callback */
>> phb->ops = &cxl_pcie_pci_ops;
>> phb->cfg_addr = NULL;
--
Alexey
Re: [RFC PATCH kernel] powerpc/pci: Get rid of unused @parent pointer in pci_controller
On Mon, 2017-11-06 at 14:24 +1100, Alexey Kardashevskiy wrote:
> The @parent pointer is supposed to point to a device which represents
> a PCI controller, however it is never set to anything and remains NULL;
> it is also quite common to pass NULL to pci_create_root_bus().
>
> Signed-off-by: Alexey Kardashevskiy
> ---
It's used for anything using of_pci_phb_probe() such as Cell.
>
> This @parent is NULL for every PHB in garrison machines, for example.
> Where would this pointer be really used?
>
> I wonder how does setting it make any difference in sysfs for CXL vphb?
>
> In general, I'd think that @parent makes sense and every PHB
> has a parent device struct like any other device and the platform
> code binds a correct device driver to a PHB and we can avoid
> having PNV_PHB_IODA2&co switches but for some reason PHBs are
> hardcoded in the platform code.
>
> ---
> arch/powerpc/include/asm/pci-bridge.h | 1 -
> arch/powerpc/kernel/pci-common.c | 2 +-
> drivers/misc/cxl/vphb.c | 3 ---
> 3 files changed, 1 insertion(+), 5 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/pci-bridge.h
> b/arch/powerpc/include/asm/pci-bridge.h
> index 752718a2949d..ad88ddeaa6b7 100644
> --- a/arch/powerpc/include/asm/pci-bridge.h
> +++ b/arch/powerpc/include/asm/pci-bridge.h
> @@ -60,7 +60,6 @@ struct pci_controller {
> #endif
> struct device_node *dn;
> struct list_head list_node;
> - struct device *parent;
>
> int first_busno;
> int last_busno;
> diff --git a/arch/powerpc/kernel/pci-common.c
> b/arch/powerpc/kernel/pci-common.c
> index 02831a396419..597576777c34 100644
> --- a/arch/powerpc/kernel/pci-common.c
> +++ b/arch/powerpc/kernel/pci-common.c
> @@ -1681,7 +1681,7 @@ void pcibios_scan_phb(struct pci_controller *hose)
> pci_add_resource(&resources, &hose->busn);
>
> /* Create an empty bus for the toplevel */
> - bus = pci_create_root_bus(hose->parent, hose->first_busno,
> + bus = pci_create_root_bus(NULL, hose->first_busno,
> hose->ops, hose, &resources);
> if (bus == NULL) {
> pr_err("Failed to create bus for PCI domain %04x\n",
> diff --git a/drivers/misc/cxl/vphb.c b/drivers/misc/cxl/vphb.c
> index 512a4897dbf6..ae3fe1563812 100644
> --- a/drivers/misc/cxl/vphb.c
> +++ b/drivers/misc/cxl/vphb.c
> @@ -232,9 +232,6 @@ int cxl_pci_vphb_add(struct cxl_afu *afu)
> if (!phb)
> return -ENODEV;
>
> - /* Setup parent in sysfs */
> - phb->parent = parent;
> -
> /* Setup the PHB using arch provided callback */
> phb->ops = &cxl_pcie_pci_ops;
> phb->cfg_addr = NULL;
[RFC PATCH kernel] powerpc/pci: Get rid of unused @parent pointer in pci_controller
The @parent pointer is supposed to point to a device which represents
a PCI controller, however it is never set to anything and remains NULL;
it is also quite common to pass NULL to pci_create_root_bus().
Signed-off-by: Alexey Kardashevskiy
---
This @parent is NULL for every PHB in garrison machines, for example.
Where would this pointer be really used?
I wonder how does setting it make any difference in sysfs for CXL vphb?
In general, I'd think that @parent makes sense and every PHB
has a parent device struct like any other device and the platform
code binds a correct device driver to a PHB and we can avoid
having PNV_PHB_IODA2&co switches but for some reason PHBs are
hardcoded in the platform code.
---
arch/powerpc/include/asm/pci-bridge.h | 1 -
arch/powerpc/kernel/pci-common.c | 2 +-
drivers/misc/cxl/vphb.c | 3 ---
3 files changed, 1 insertion(+), 5 deletions(-)
diff --git a/arch/powerpc/include/asm/pci-bridge.h
b/arch/powerpc/include/asm/pci-bridge.h
index 752718a2949d..ad88ddeaa6b7 100644
--- a/arch/powerpc/include/asm/pci-bridge.h
+++ b/arch/powerpc/include/asm/pci-bridge.h
@@ -60,7 +60,6 @@ struct pci_controller {
#endif
struct device_node *dn;
struct list_head list_node;
- struct device *parent;
int first_busno;
int last_busno;
diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c
index 02831a396419..597576777c34 100644
--- a/arch/powerpc/kernel/pci-common.c
+++ b/arch/powerpc/kernel/pci-common.c
@@ -1681,7 +1681,7 @@ void pcibios_scan_phb(struct pci_controller *hose)
pci_add_resource(&resources, &hose->busn);
/* Create an empty bus for the toplevel */
- bus = pci_create_root_bus(hose->parent, hose->first_busno,
+ bus = pci_create_root_bus(NULL, hose->first_busno,
hose->ops, hose, &resources);
if (bus == NULL) {
pr_err("Failed to create bus for PCI domain %04x\n",
diff --git a/drivers/misc/cxl/vphb.c b/drivers/misc/cxl/vphb.c
index 512a4897dbf6..ae3fe1563812 100644
--- a/drivers/misc/cxl/vphb.c
+++ b/drivers/misc/cxl/vphb.c
@@ -232,9 +232,6 @@ int cxl_pci_vphb_add(struct cxl_afu *afu)
if (!phb)
return -ENODEV;
- /* Setup parent in sysfs */
- phb->parent = parent;
-
/* Setup the PHB using arch provided callback */
phb->ops = &cxl_pcie_pci_ops;
phb->cfg_addr = NULL;
--
2.11.0
