[PATCH] PCI: tegra: Add debugfs support

[PATCH] PCI: tegra: Add debugfs support

[Thierry Reding]

From: Thierry Reding <treding@nvidia.com>

Provide a debugfs file that shows the current link status for each root
port.

Signed-off-by: Thierry Reding <treding@nvidia.com>
---
 drivers/pci/host/pci-tegra.c | 118 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 118 insertions(+)

diff --git a/drivers/pci/host/pci-tegra.c b/drivers/pci/host/pci-tegra.c
index 14ec5b2c69e0..49b3bd5f5926 100644
--- a/drivers/pci/host/pci-tegra.c
+++ b/drivers/pci/host/pci-tegra.c
@@ -25,6 +25,7 @@
  */
 
 #include <linux/clk.h>
+#include <linux/debugfs.h>
 #include <linux/delay.h>
 #include <linux/export.h>
 #include <linux/interrupt.h>
@@ -275,6 +276,7 @@ struct tegra_pcie {
 	unsigned int num_supplies;
 
 	const struct tegra_pcie_soc_data *soc_data;
+	struct dentry *debugfs;
 };
 
 struct tegra_pcie_port {
@@ -1664,6 +1666,115 @@ static const struct of_device_id tegra_pcie_of_match[] = {
 };
 MODULE_DEVICE_TABLE(of, tegra_pcie_of_match);
 
+static void *tegra_pcie_ports_seq_start(struct seq_file *s, loff_t *pos)
+{
+	struct tegra_pcie *pcie = s->private;
+
+	if (list_empty(&pcie->ports))
+		return NULL;
+
+	seq_printf(s, "Index  Status\n");
+
+	return seq_list_start(&pcie->ports, *pos);
+}
+
+static void *tegra_pcie_ports_seq_next(struct seq_file *s, void *v, loff_t *pos)
+{
+	struct tegra_pcie *pcie = s->private;
+
+	return seq_list_next(v, &pcie->ports, pos);
+}
+
+static void tegra_pcie_ports_seq_stop(struct seq_file *s, void *v)
+{
+}
+
+static int tegra_pcie_ports_seq_show(struct seq_file *s, void *v)
+{
+	bool up = false, active = false;
+	struct tegra_pcie_port *port;
+	unsigned int value;
+
+	port = list_entry(v, struct tegra_pcie_port, list);
+
+	value = readl(port->base + RP_VEND_XP);
+
+	if (value & RP_VEND_XP_DL_UP)
+		up = true;
+
+	value = readl(port->base + RP_LINK_CONTROL_STATUS);
+
+	if (value & RP_LINK_CONTROL_STATUS_DL_LINK_ACTIVE)
+		active = true;
+
+	seq_printf(s, "%2u     ", port->index);
+
+	if (up)
+		seq_printf(s, "up");
+
+	if (active) {
+		if (up)
+			seq_printf(s, ", ");
+
+		seq_printf(s, "active");
+	}
+
+	seq_printf(s, "\n");
+	return 0;
+}
+
+static const struct seq_operations tegra_pcie_ports_seq_ops = {
+	.start = tegra_pcie_ports_seq_start,
+	.next = tegra_pcie_ports_seq_next,
+	.stop = tegra_pcie_ports_seq_stop,
+	.show = tegra_pcie_ports_seq_show,
+};
+
+static int tegra_pcie_ports_open(struct inode *inode, struct file *file)
+{
+	struct tegra_pcie *pcie = inode->i_private;
+	struct seq_file *s;
+	int err;
+
+	err = seq_open(file, &tegra_pcie_ports_seq_ops);
+	if (err)
+		return err;
+
+	s = file->private_data;
+	s->private = pcie;
+
+	return 0;
+}
+
+static const struct file_operations tegra_pcie_ports_ops = {
+	.owner = THIS_MODULE,
+	.open = tegra_pcie_ports_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = seq_release,
+};
+
+static int tegra_pcie_debugfs_init(struct tegra_pcie *pcie)
+{
+	struct dentry *file;
+
+	pcie->debugfs = debugfs_create_dir("pcie", NULL);
+	if (!pcie->debugfs)
+		return -ENOMEM;
+
+	file = debugfs_create_file("ports", S_IFREG | S_IRUGO, pcie->debugfs,
+				   pcie, &tegra_pcie_ports_ops);
+	if (!file)
+		goto remove;
+
+	return 0;
+
+remove:
+	debugfs_remove_recursive(pcie->debugfs);
+	pcie->debugfs = NULL;
+	return -ENOMEM;
+}
+
 static int tegra_pcie_probe(struct platform_device *pdev)
 {
 	const struct of_device_id *match;
@@ -1718,6 +1829,13 @@ static int tegra_pcie_probe(struct platform_device *pdev)
 		goto disable_msi;
 	}
 
+	if (IS_ENABLED(CONFIG_DEBUG_FS)) {
+		err = tegra_pcie_debugfs_init(pcie);
+		if (err < 0)
+			dev_err(&pdev->dev, "failed to setup debugfs: %d\n",
+				err);
+	}
+
 	platform_set_drvdata(pdev, pcie);
 	return 0;
 
-- 
2.0.1

Re: [PATCH] PCI: tegra: Add debugfs support

[Stephen Warren]

On 07/11/2014 01:00 AM, Thierry Reding wrote:
> From: Thierry Reding <treding@nvidia.com>
> 
> Provide a debugfs file that shows the current link status for each root
> port.

Reviewed-by: Stephen Warren <swarren@nvidia.com>

Does this patch conflict with or merge well with the Tegra124 PCIe
driver patches, I wonder?

Re: [PATCH] PCI: tegra: Add debugfs support

[Thierry Reding]

[-- Attachment #1: Type: text/plain, Size: 834 bytes --]

On Mon, Jul 21, 2014 at 09:54:50AM -0600, Stephen Warren wrote:
> On 07/11/2014 01:00 AM, Thierry Reding wrote:
> > From: Thierry Reding <treding@nvidia.com>
> > 
> > Provide a debugfs file that shows the current link status for each root
> > port.
> 
> Reviewed-by: Stephen Warren <swarren@nvidia.com>
> 
> Does this patch conflict with or merge well with the Tegra124 PCIe
> driver patches, I wonder?

Yes. The Tegra124 PCIe patches are part of the same branch. My plan was
to get this merged for 3.17 (if it's not too late yet) and then submit
Tegra124 support for 3.18 soonish after 3.17 is released.

I also have a bunch of patches that allow the Tegra PCIe driver to be
built as a module (though that has even more cross-tree dependencies, so
should probably be phased in over a couple of cycles).

Thierry

[-- Attachment #2: Type: application/pgp-signature, Size: 836 bytes --]

Re: [PATCH] PCI: tegra: Add debugfs support

[Bjorn Helgaas]

On Fri, Jul 11, 2014 at 09:00:24AM +0200, Thierry Reding wrote:
> From: Thierry Reding <treding@nvidia.com>
> 
> Provide a debugfs file that shows the current link status for each root
> port.
> 
> Signed-off-by: Thierry Reding <treding@nvidia.com>

I applied this with Stephen's ack to my pci/host-tegra branch for v3.17.
Let me know if you prefer a different merge strategy.  I'll be on vacation
until Aug 11, so it won't be in my first pull request, but I plan to do
another for things like this.

> ---
>  drivers/pci/host/pci-tegra.c | 118 +++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 118 insertions(+)
> 
> diff --git a/drivers/pci/host/pci-tegra.c b/drivers/pci/host/pci-tegra.c
> index 14ec5b2c69e0..49b3bd5f5926 100644
> --- a/drivers/pci/host/pci-tegra.c
> +++ b/drivers/pci/host/pci-tegra.c
> @@ -25,6 +25,7 @@
>   */
>  
>  #include <linux/clk.h>
> +#include <linux/debugfs.h>
>  #include <linux/delay.h>
>  #include <linux/export.h>
>  #include <linux/interrupt.h>
> @@ -275,6 +276,7 @@ struct tegra_pcie {
>  	unsigned int num_supplies;
>  
>  	const struct tegra_pcie_soc_data *soc_data;
> +	struct dentry *debugfs;
>  };
>  
>  struct tegra_pcie_port {
> @@ -1664,6 +1666,115 @@ static const struct of_device_id tegra_pcie_of_match[] = {
>  };
>  MODULE_DEVICE_TABLE(of, tegra_pcie_of_match);
>  
> +static void *tegra_pcie_ports_seq_start(struct seq_file *s, loff_t *pos)
> +{
> +	struct tegra_pcie *pcie = s->private;
> +
> +	if (list_empty(&pcie->ports))
> +		return NULL;
> +
> +	seq_printf(s, "Index  Status\n");
> +
> +	return seq_list_start(&pcie->ports, *pos);
> +}
> +
> +static void *tegra_pcie_ports_seq_next(struct seq_file *s, void *v, loff_t *pos)
> +{
> +	struct tegra_pcie *pcie = s->private;
> +
> +	return seq_list_next(v, &pcie->ports, pos);
> +}
> +
> +static void tegra_pcie_ports_seq_stop(struct seq_file *s, void *v)
> +{
> +}
> +
> +static int tegra_pcie_ports_seq_show(struct seq_file *s, void *v)
> +{
> +	bool up = false, active = false;
> +	struct tegra_pcie_port *port;
> +	unsigned int value;
> +
> +	port = list_entry(v, struct tegra_pcie_port, list);
> +
> +	value = readl(port->base + RP_VEND_XP);
> +
> +	if (value & RP_VEND_XP_DL_UP)
> +		up = true;
> +
> +	value = readl(port->base + RP_LINK_CONTROL_STATUS);
> +
> +	if (value & RP_LINK_CONTROL_STATUS_DL_LINK_ACTIVE)
> +		active = true;
> +
> +	seq_printf(s, "%2u     ", port->index);
> +
> +	if (up)
> +		seq_printf(s, "up");
> +
> +	if (active) {
> +		if (up)
> +			seq_printf(s, ", ");
> +
> +		seq_printf(s, "active");
> +	}
> +
> +	seq_printf(s, "\n");
> +	return 0;
> +}
> +
> +static const struct seq_operations tegra_pcie_ports_seq_ops = {
> +	.start = tegra_pcie_ports_seq_start,
> +	.next = tegra_pcie_ports_seq_next,
> +	.stop = tegra_pcie_ports_seq_stop,
> +	.show = tegra_pcie_ports_seq_show,
> +};
> +
> +static int tegra_pcie_ports_open(struct inode *inode, struct file *file)
> +{
> +	struct tegra_pcie *pcie = inode->i_private;
> +	struct seq_file *s;
> +	int err;
> +
> +	err = seq_open(file, &tegra_pcie_ports_seq_ops);
> +	if (err)
> +		return err;
> +
> +	s = file->private_data;
> +	s->private = pcie;
> +
> +	return 0;
> +}
> +
> +static const struct file_operations tegra_pcie_ports_ops = {
> +	.owner = THIS_MODULE,
> +	.open = tegra_pcie_ports_open,
> +	.read = seq_read,
> +	.llseek = seq_lseek,
> +	.release = seq_release,
> +};
> +
> +static int tegra_pcie_debugfs_init(struct tegra_pcie *pcie)
> +{
> +	struct dentry *file;
> +
> +	pcie->debugfs = debugfs_create_dir("pcie", NULL);
> +	if (!pcie->debugfs)
> +		return -ENOMEM;
> +
> +	file = debugfs_create_file("ports", S_IFREG | S_IRUGO, pcie->debugfs,
> +				   pcie, &tegra_pcie_ports_ops);
> +	if (!file)
> +		goto remove;
> +
> +	return 0;
> +
> +remove:
> +	debugfs_remove_recursive(pcie->debugfs);
> +	pcie->debugfs = NULL;
> +	return -ENOMEM;
> +}
> +
>  static int tegra_pcie_probe(struct platform_device *pdev)
>  {
>  	const struct of_device_id *match;
> @@ -1718,6 +1829,13 @@ static int tegra_pcie_probe(struct platform_device *pdev)
>  		goto disable_msi;
>  	}
>  
> +	if (IS_ENABLED(CONFIG_DEBUG_FS)) {
> +		err = tegra_pcie_debugfs_init(pcie);
> +		if (err < 0)
> +			dev_err(&pdev->dev, "failed to setup debugfs: %d\n",
> +				err);
> +	}
> +
>  	platform_set_drvdata(pdev, pcie);
>  	return 0;
>  
> -- 
> 2.0.1
>