diff mbox series

[v1,3/8] PCI: brcmstb: Use bridge reset if available

Message ID 20240628205430.24775-4-james.quinlan@broadcom.com (mailing list archive)
State Superseded
Delegated to: Krzysztof Wilczyński
Headers show
Series PCI: brcnstb: Enable STB 7712 SOC | expand

Commit Message

Jim Quinlan June 28, 2024, 8:54 p.m. UTC
The 7712 SOC has a bridge reset which can be described in the device tree.
If it is present, use it. Otherwise, continue to use the legacy method to
reset the bridge.

Signed-off-by: Jim Quinlan <james.quinlan@broadcom.com>
---
 drivers/pci/controller/pcie-brcmstb.c | 24 +++++++++++++++++++-----
 1 file changed, 19 insertions(+), 5 deletions(-)

Comments

Stanimir Varbanov July 2, 2024, 12:59 p.m. UTC | #1
On 6/28/24 23:54, Jim Quinlan wrote:
> The 7712 SOC has a bridge reset which can be described in the device tree.
> If it is present, use it. Otherwise, continue to use the legacy method to
> reset the bridge.
> 
> Signed-off-by: Jim Quinlan <james.quinlan@broadcom.com>
> ---
>  drivers/pci/controller/pcie-brcmstb.c | 24 +++++++++++++++++++-----
>  1 file changed, 19 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
> index c2eb29b886f7..4104c3668fdb 100644
> --- a/drivers/pci/controller/pcie-brcmstb.c
> +++ b/drivers/pci/controller/pcie-brcmstb.c
> @@ -265,6 +265,7 @@ struct brcm_pcie {
>  	enum pcie_type		type;
>  	struct reset_control	*rescal;
>  	struct reset_control	*perst_reset;
> +	struct reset_control	*bridge;
>  	int			num_memc;
>  	u64			memc_size[PCIE_BRCM_MAX_MEMC];
>  	u32			hw_rev;
> @@ -732,12 +733,19 @@ static void __iomem *brcm7425_pcie_map_bus(struct pci_bus *bus,
>  
>  static void brcm_pcie_bridge_sw_init_set_generic(struct brcm_pcie *pcie, u32 val)
>  {
> -	u32 tmp, mask =  RGR1_SW_INIT_1_INIT_GENERIC_MASK;
> -	u32 shift = RGR1_SW_INIT_1_INIT_GENERIC_SHIFT;
> +	if (pcie->bridge) {
> +		if (val)
> +			reset_control_assert(pcie->bridge);
> +		else
> +			reset_control_deassert(pcie->bridge);

Please check reset_control_assert/deassert() calls for error. This might
need to change the definition of brcm_pcie_bridge_sw_init_set_generic()
to return error.

~Stan
Jim Quinlan July 2, 2024, 6:36 p.m. UTC | #2
On Tue, Jul 2, 2024 at 8:59 AM Stanimir Varbanov <svarbanov@suse.de> wrote:
>
>
>
> On 6/28/24 23:54, Jim Quinlan wrote:
> > The 7712 SOC has a bridge reset which can be described in the device tree.
> > If it is present, use it. Otherwise, continue to use the legacy method to
> > reset the bridge.
> >
> > Signed-off-by: Jim Quinlan <james.quinlan@broadcom.com>
> > ---
> >  drivers/pci/controller/pcie-brcmstb.c | 24 +++++++++++++++++++-----
> >  1 file changed, 19 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
> > index c2eb29b886f7..4104c3668fdb 100644
> > --- a/drivers/pci/controller/pcie-brcmstb.c
> > +++ b/drivers/pci/controller/pcie-brcmstb.c
> > @@ -265,6 +265,7 @@ struct brcm_pcie {
> >       enum pcie_type          type;
> >       struct reset_control    *rescal;
> >       struct reset_control    *perst_reset;
> > +     struct reset_control    *bridge;
> >       int                     num_memc;
> >       u64                     memc_size[PCIE_BRCM_MAX_MEMC];
> >       u32                     hw_rev;
> > @@ -732,12 +733,19 @@ static void __iomem *brcm7425_pcie_map_bus(struct pci_bus *bus,
> >
> >  static void brcm_pcie_bridge_sw_init_set_generic(struct brcm_pcie *pcie, u32 val)
> >  {
> > -     u32 tmp, mask =  RGR1_SW_INIT_1_INIT_GENERIC_MASK;
> > -     u32 shift = RGR1_SW_INIT_1_INIT_GENERIC_SHIFT;
> > +     if (pcie->bridge) {
> > +             if (val)
> > +                     reset_control_assert(pcie->bridge);
> > +             else
> > +                     reset_control_deassert(pcie->bridge);
>
> Please check reset_control_assert/deassert() calls for error. This might
> need to change the definition of brcm_pcie_bridge_sw_init_set_generic()
> to return error.

Hi Stan,

Do you really think this is necessary?  If you look at
"drivers/reset/reset-brcmstb.c"  there is no way for either of these
calls to fail and I don't see that changing because it is just writing
a bit into a register.

Regards,
Jim Quinlan
Broadcom STB/CM
>
> ~Stan
Stanimir Varbanov July 3, 2024, 1:09 p.m. UTC | #3
Hi Jim,

On 7/2/24 21:36, Jim Quinlan wrote:
> On Tue, Jul 2, 2024 at 8:59 AM Stanimir Varbanov <svarbanov@suse.de> wrote:
>>
>>
>>
>> On 6/28/24 23:54, Jim Quinlan wrote:
>>> The 7712 SOC has a bridge reset which can be described in the device tree.
>>> If it is present, use it. Otherwise, continue to use the legacy method to
>>> reset the bridge.
>>>
>>> Signed-off-by: Jim Quinlan <james.quinlan@broadcom.com>
>>> ---
>>>  drivers/pci/controller/pcie-brcmstb.c | 24 +++++++++++++++++++-----
>>>  1 file changed, 19 insertions(+), 5 deletions(-)
>>>
>>> diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
>>> index c2eb29b886f7..4104c3668fdb 100644
>>> --- a/drivers/pci/controller/pcie-brcmstb.c
>>> +++ b/drivers/pci/controller/pcie-brcmstb.c
>>> @@ -265,6 +265,7 @@ struct brcm_pcie {
>>>       enum pcie_type          type;
>>>       struct reset_control    *rescal;
>>>       struct reset_control    *perst_reset;
>>> +     struct reset_control    *bridge;
>>>       int                     num_memc;
>>>       u64                     memc_size[PCIE_BRCM_MAX_MEMC];
>>>       u32                     hw_rev;
>>> @@ -732,12 +733,19 @@ static void __iomem *brcm7425_pcie_map_bus(struct pci_bus *bus,
>>>
>>>  static void brcm_pcie_bridge_sw_init_set_generic(struct brcm_pcie *pcie, u32 val)
>>>  {
>>> -     u32 tmp, mask =  RGR1_SW_INIT_1_INIT_GENERIC_MASK;
>>> -     u32 shift = RGR1_SW_INIT_1_INIT_GENERIC_SHIFT;
>>> +     if (pcie->bridge) {
>>> +             if (val)
>>> +                     reset_control_assert(pcie->bridge);
>>> +             else
>>> +                     reset_control_deassert(pcie->bridge);
>>
>> Please check reset_control_assert/deassert() calls for error. This might
>> need to change the definition of brcm_pcie_bridge_sw_init_set_generic()
>> to return error.
> 
> Hi Stan,
> 
> Do you really think this is necessary?  If you look at
> "drivers/reset/reset-brcmstb.c"  there is no way for either of these
> calls to fail and I don't see that changing because it is just writing
> a bit into a register.

yes, I think there are kernel rules which we have to follow. We use
generic reset-control interface in pcie driver and we cannot rely on the
low-level implementation of this particular reset-controller driver
(reset-brcmstb.c).

regards,
~Stan
diff mbox series

Patch

diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
index c2eb29b886f7..4104c3668fdb 100644
--- a/drivers/pci/controller/pcie-brcmstb.c
+++ b/drivers/pci/controller/pcie-brcmstb.c
@@ -265,6 +265,7 @@  struct brcm_pcie {
 	enum pcie_type		type;
 	struct reset_control	*rescal;
 	struct reset_control	*perst_reset;
+	struct reset_control	*bridge;
 	int			num_memc;
 	u64			memc_size[PCIE_BRCM_MAX_MEMC];
 	u32			hw_rev;
@@ -732,12 +733,19 @@  static void __iomem *brcm7425_pcie_map_bus(struct pci_bus *bus,
 
 static void brcm_pcie_bridge_sw_init_set_generic(struct brcm_pcie *pcie, u32 val)
 {
-	u32 tmp, mask =  RGR1_SW_INIT_1_INIT_GENERIC_MASK;
-	u32 shift = RGR1_SW_INIT_1_INIT_GENERIC_SHIFT;
+	if (pcie->bridge) {
+		if (val)
+			reset_control_assert(pcie->bridge);
+		else
+			reset_control_deassert(pcie->bridge);
+	} else {
+		u32 tmp, mask =  RGR1_SW_INIT_1_INIT_GENERIC_MASK;
+		u32 shift = RGR1_SW_INIT_1_INIT_GENERIC_SHIFT;
 
-	tmp = readl(pcie->base + PCIE_RGR1_SW_INIT_1(pcie));
-	tmp = (tmp & ~mask) | ((val << shift) & mask);
-	writel(tmp, pcie->base + PCIE_RGR1_SW_INIT_1(pcie));
+		tmp = readl(pcie->base + PCIE_RGR1_SW_INIT_1(pcie));
+		tmp = (tmp & ~mask) | ((val << shift) & mask);
+		writel(tmp, pcie->base + PCIE_RGR1_SW_INIT_1(pcie));
+	}
 }
 
 static void brcm_pcie_bridge_sw_init_set_7278(struct brcm_pcie *pcie, u32 val)
@@ -1635,6 +1643,12 @@  static int brcm_pcie_probe(struct platform_device *pdev)
 		goto clk_out;
 	}
 
+	pcie->bridge = devm_reset_control_get_optional_exclusive(&pdev->dev, "bridge");
+	if (IS_ERR(pcie->bridge)) {
+		ret = PTR_ERR(pcie->bridge);
+		goto clk_out;
+	}
+
 	ret = brcm_phy_start(pcie);
 	if (ret) {
 		reset_control_rearm(pcie->rescal);