[PATCH 1/3] PCI: apple: GPIO handling nitfixes

[PATCH 1/3] PCI: apple: GPIO handling nitfixes

[Hector Martin]

- Use devm managed GPIO getter
- GPIO ops can sleep in this context

Fixes: 1e33888fbe44 ("PCI: apple: Add initial hardware bring-up")
Cc: stable@vger.kernel.org
Signed-off-by: Hector Martin <marcan@marcan.st>
---
 drivers/pci/controller/pcie-apple.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/pci/controller/pcie-apple.c b/drivers/pci/controller/pcie-apple.c
index a2c3c207a04b..e0c06c0ee731 100644
--- a/drivers/pci/controller/pcie-apple.c
+++ b/drivers/pci/controller/pcie-apple.c
@@ -516,8 +516,8 @@ static int apple_pcie_setup_port(struct apple_pcie *pcie,
 	u32 stat, idx;
 	int ret, i;
 
-	reset = gpiod_get_from_of_node(np, "reset-gpios", 0,
-				       GPIOD_OUT_LOW, "PERST#");
+	reset = devm_gpiod_get_from_of_node(pcie->dev, np, "reset-gpios", 0,
+					    GPIOD_OUT_LOW, "PERST#");
 	if (IS_ERR(reset))
 		return PTR_ERR(reset);
 
@@ -541,7 +541,7 @@ static int apple_pcie_setup_port(struct apple_pcie *pcie,
 	rmw_set(PORT_APPCLK_EN, port->base + PORT_APPCLK);
 
 	/* Assert PERST# before setting up the clock */
-	gpiod_set_value(reset, 1);
+	gpiod_set_value_cansleep(reset, 1);
 
 	ret = apple_pcie_setup_refclk(pcie, port);
 	if (ret < 0)
@@ -552,7 +552,7 @@ static int apple_pcie_setup_port(struct apple_pcie *pcie,
 
 	/* Deassert PERST# */
 	rmw_set(PORT_PERST_OFF, port->base + PORT_PERST);
-	gpiod_set_value(reset, 0);
+	gpiod_set_value_cansleep(reset, 0);
 
 	/* Wait for 100ms after PERST# deassertion (PCIe r5.0, 6.6.1) */
 	msleep(100);
-- 
2.35.1

Re: [PATCH 1/3] PCI: apple: GPIO handling nitfixes

[Marc Zyngier]

On Mon, 02 May 2022 10:38:30 +0100,
Hector Martin <marcan@marcan.st> wrote:
> 
> - Use devm managed GPIO getter
> - GPIO ops can sleep in this context
> 
> Fixes: 1e33888fbe44 ("PCI: apple: Add initial hardware bring-up")
> Cc: stable@vger.kernel.org

Why the Cc: stable? I'd guess that at a push, the devm_*() usage help
with potential memory leaks when the driver fails to probe, but it
would be good to call that out in the commit message.

> Signed-off-by: Hector Martin <marcan@marcan.st>
> ---
>  drivers/pci/controller/pcie-apple.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/pci/controller/pcie-apple.c b/drivers/pci/controller/pcie-apple.c
> index a2c3c207a04b..e0c06c0ee731 100644
> --- a/drivers/pci/controller/pcie-apple.c
> +++ b/drivers/pci/controller/pcie-apple.c
> @@ -516,8 +516,8 @@ static int apple_pcie_setup_port(struct apple_pcie *pcie,
>  	u32 stat, idx;
>  	int ret, i;
>  
> -	reset = gpiod_get_from_of_node(np, "reset-gpios", 0,
> -				       GPIOD_OUT_LOW, "PERST#");
> +	reset = devm_gpiod_get_from_of_node(pcie->dev, np, "reset-gpios", 0,
> +					    GPIOD_OUT_LOW, "PERST#");
>  	if (IS_ERR(reset))
>  		return PTR_ERR(reset);
>  
> @@ -541,7 +541,7 @@ static int apple_pcie_setup_port(struct apple_pcie *pcie,
>  	rmw_set(PORT_APPCLK_EN, port->base + PORT_APPCLK);
>  
>  	/* Assert PERST# before setting up the clock */
> -	gpiod_set_value(reset, 1);
> +	gpiod_set_value_cansleep(reset, 1);
>  
>  	ret = apple_pcie_setup_refclk(pcie, port);
>  	if (ret < 0)
> @@ -552,7 +552,7 @@ static int apple_pcie_setup_port(struct apple_pcie *pcie,
>  
>  	/* Deassert PERST# */
>  	rmw_set(PORT_PERST_OFF, port->base + PORT_PERST);
> -	gpiod_set_value(reset, 0);
> +	gpiod_set_value_cansleep(reset, 0);
>  
>  	/* Wait for 100ms after PERST# deassertion (PCIe r5.0, 6.6.1) */
>  	msleep(100);

Otherwise:

Acked-by: Marc Zyngier <maz@kernel.org>

	M.

-- 
Without deviation from the norm, progress is not possible.

Re: [PATCH 1/3] PCI: apple: GPIO handling nitfixes

[Hector Martin]

On 02/05/2022 19.20, Marc Zyngier wrote:
> On Mon, 02 May 2022 10:38:30 +0100,
> Hector Martin <marcan@marcan.st> wrote:
>>
>> - Use devm managed GPIO getter
>> - GPIO ops can sleep in this context
>>
>> Fixes: 1e33888fbe44 ("PCI: apple: Add initial hardware bring-up")
>> Cc: stable@vger.kernel.org
> 
> Why the Cc: stable? I'd guess that at a push, the devm_*() usage help
> with potential memory leaks when the driver fails to probe, but it
> would be good to call that out in the commit message.

Ack, I mentioned what this fixes for v2 and reworded the commit message.

-- 
Hector Martin (marcan@marcan.st)
Public Key: https://mrcn.st/pub

Re: [PATCH 1/3] PCI: apple: GPIO handling nitfixes

[Greg KH]

On Mon, May 02, 2022 at 06:38:30PM +0900, Hector Martin wrote:
> - Use devm managed GPIO getter
> - GPIO ops can sleep in this context

Please read the section entitled "The canonical patch format" in the
kernel file, Documentation/SubmittingPatches for what is needed in order
to properly describe the change.  This text does not make any sense.

Same for your subject, it needs to be reworked.

thanks,

greg k-h

[PATCH 2/3] PCI: apple: Probe all GPIOs for availability first

[Hector Martin]

If we're probing the PCI controller and some GPIOs are not available and
cause a probe defer, we can end up leaving some ports initialized and
not others and making a mess.

Check for PERST# GPIOs for all ports first, and just return
-EPROBE_DEFER if any are not ready yet, without bringing anything up.

Fixes: 1e33888fbe44 ("PCI: apple: Add initial hardware bring-up")
Cc: stable@vger.kernel.org
Signed-off-by: Hector Martin <marcan@marcan.st>
---
 drivers/pci/controller/pcie-apple.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/drivers/pci/controller/pcie-apple.c b/drivers/pci/controller/pcie-apple.c
index e0c06c0ee731..e3aa2d461739 100644
--- a/drivers/pci/controller/pcie-apple.c
+++ b/drivers/pci/controller/pcie-apple.c
@@ -507,6 +507,20 @@ static u32 apple_pcie_rid2sid_write(struct apple_pcie_port *port,
 	return readl_relaxed(port->base + PORT_RID2SID(idx));
 }
 
+static int apple_pcie_probe_port(struct device_node *np)
+{
+	struct gpio_desc *gd;
+
+	gd = gpiod_get_from_of_node(np, "reset-gpios", 0,
+				    GPIOD_OUT_LOW, "PERST#");
+	if (IS_ERR(gd)) {
+		return PTR_ERR(gd);
+	}
+
+	gpiod_put(gd);
+	return 0;
+}
+
 static int apple_pcie_setup_port(struct apple_pcie *pcie,
 				 struct device_node *np)
 {
@@ -797,8 +811,18 @@ static int apple_pcie_init(struct pci_config_window *cfg)
 
 static int apple_pcie_probe(struct platform_device *pdev)
 {
+	struct device *dev = &pdev->dev;
+	struct device_node *of_port;
 	int ret;
 
+	/* Check for probe dependencies for all ports first */
+	for_each_child_of_node(dev->of_node, of_port) {
+		ret = apple_pcie_probe_port(of_port);
+		of_node_put(of_port);
+		if (ret)
+			return dev_err_probe(dev, ret, "Port %pOF probe fail\n", of_port);
+	}
+
 	ret = bus_register_notifier(&pci_bus_type, &apple_pcie_nb);
 	if (ret)
 		return ret;
-- 
2.35.1

Re: [PATCH 2/3] PCI: apple: Probe all GPIOs for availability first

[Marc Zyngier]

On Mon, 02 May 2022 10:38:31 +0100,
Hector Martin <marcan@marcan.st> wrote:
> 
> If we're probing the PCI controller and some GPIOs are not available and
> cause a probe defer, we can end up leaving some ports initialized and
> not others and making a mess.
> 
> Check for PERST# GPIOs for all ports first, and just return
> -EPROBE_DEFER if any are not ready yet, without bringing anything up.
> 
> Fixes: 1e33888fbe44 ("PCI: apple: Add initial hardware bring-up")
> Cc: stable@vger.kernel.org
> Signed-off-by: Hector Martin <marcan@marcan.st>
> ---
>  drivers/pci/controller/pcie-apple.c | 24 ++++++++++++++++++++++++
>  1 file changed, 24 insertions(+)
> 
> diff --git a/drivers/pci/controller/pcie-apple.c b/drivers/pci/controller/pcie-apple.c
> index e0c06c0ee731..e3aa2d461739 100644
> --- a/drivers/pci/controller/pcie-apple.c
> +++ b/drivers/pci/controller/pcie-apple.c
> @@ -507,6 +507,20 @@ static u32 apple_pcie_rid2sid_write(struct apple_pcie_port *port,
>  	return readl_relaxed(port->base + PORT_RID2SID(idx));
>  }
>  
> +static int apple_pcie_probe_port(struct device_node *np)
> +{
> +	struct gpio_desc *gd;
> +
> +	gd = gpiod_get_from_of_node(np, "reset-gpios", 0,
> +				    GPIOD_OUT_LOW, "PERST#");
> +	if (IS_ERR(gd)) {
> +		return PTR_ERR(gd);
> +	}
> +
> +	gpiod_put(gd);
> +	return 0;
> +}
> +
>  static int apple_pcie_setup_port(struct apple_pcie *pcie,
>  				 struct device_node *np)
>  {
> @@ -797,8 +811,18 @@ static int apple_pcie_init(struct pci_config_window *cfg)
>  
>  static int apple_pcie_probe(struct platform_device *pdev)
>  {
> +	struct device *dev = &pdev->dev;
> +	struct device_node *of_port;
>  	int ret;
>  
> +	/* Check for probe dependencies for all ports first */
> +	for_each_child_of_node(dev->of_node, of_port) {
> +		ret = apple_pcie_probe_port(of_port);
> +		of_node_put(of_port);
> +		if (ret)
> +			return dev_err_probe(dev, ret, "Port %pOF probe fail\n", of_port);
> +	}
> +
>  	ret = bus_register_notifier(&pci_bus_type, &apple_pcie_nb);
>  	if (ret)
>  		return ret;

Acked-by: Marc Zyngier <maz@kernel.org>

	M.

-- 
Without deviation from the norm, progress is not possible.