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

[Bjorn Helgaas <bhelgaas-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>]

On Fri, Jul 11, 2014 at 09:00:24AM +0200, Thierry Reding wrote:
> From: Thierry Reding <treding-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
> 
> Provide a debugfs file that shows the current link status for each root
> port.
> 
> Signed-off-by: Thierry Reding <treding-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>

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
>