diff mbox series

[1/2] PCI: loongson: add skip-scan property for child DT node

Message ID 20221103090040.836-1-liupeibao@loongson.cn
State New
Headers
Series [1/2] PCI: loongson: add skip-scan property for child DT node |

Commit Message

Liu Peibao Nov. 3, 2022, 9 a.m. UTC 
  The PCI Controller of 2k1000 could not mask devices by
setting vender id & device id in configuration space header
as invalid values. When there are pins shareble between
the platform device and PCI device, if the platform device
is preferred, we should not scan this PCI device. In the
above scene, add "skip-scan" property in DT node of this
PCI device.

Signed-off-by: Liu Peibao <liupeibao@loongson.cn>
---
 drivers/pci/controller/pci-loongson.c | 62 +++++++++++++++++++++++++++
 1 file changed, 62 insertions(+)

Comments

Jiaxun Yang Nov. 3, 2022, 11:37 a.m. UTC | #1 
在 2022/11/3 09:00, Liu Peibao 写道:
> The PCI Controller of 2k1000 could not mask devices by
> setting vender id & device id in configuration space header
> as invalid values. When there are pins shareble between
> the platform device and PCI device, if the platform device
> is preferred, we should not scan this PCI device. In the
> above scene, add "skip-scan" property in DT node of this
> PCI device.

If you are going to add a new property you need to document it somewhere.

 From my point of view you can use existing property `status = "disabled"`
to for this semantic...

Thanks.
- Jiaxun


>
> Signed-off-by: Liu Peibao <liupeibao@loongson.cn>
> ---
>
Liu Peibao Nov. 4, 2022, 6:36 a.m. UTC | #2 
On 11/3/22 7:37 PM, Jiaxun Yang wrote:
> 
> 
> 在 2022/11/3 09:00, Liu Peibao 写道:
>> The PCI Controller of 2k1000 could not mask devices by
>> setting vender id & device id in configuration space header
>> as invalid values. When there are pins shareble between
>> the platform device and PCI device, if the platform device
>> is preferred, we should not scan this PCI device. In the
>> above scene, add "skip-scan" property in DT node of this
>> PCI device.
> 
> If you are going to add a new property you need to document it somewhere.
> 
> From my point of view you can use existing property `status = "disabled"`
> to for this semantic...
> 
That is really constructive. I will let it work with `status = "disabled"`.

BR,
Peibao
Dan Carpenter Nov. 17, 2022, 4:12 a.m. UTC | #3 
Hi Liu,

https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Liu-Peibao/PCI-loongson-add-skip-scan-property-for-child-DT-node/20221103-170125
base:   https://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci.git next
patch link:    https://lore.kernel.org/r/20221103090040.836-1-liupeibao%40loongson.cn
patch subject: [PATCH 1/2] PCI: loongson: add skip-scan property for child DT node
config: loongarch-randconfig-m041-20221114
compiler: loongarch64-linux-gcc (GCC) 12.1.0

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
| Reported-by: Dan Carpenter <error27@gmail.com>

smatch warnings:
drivers/pci/controller/pci-loongson.c:257 setup_masklist() error: not allocating enough for = 'entry' 24 vs 8

vim +/entry +257 drivers/pci/controller/pci-loongson.c

f93e71fb8e65ba Liu Peibao  2022-11-03  242  static int setup_masklist(struct loongson_pci *priv)
f93e71fb8e65ba Liu Peibao  2022-11-03  243  {
f93e71fb8e65ba Liu Peibao  2022-11-03  244  	struct device *dev = &priv->pdev->dev;
f93e71fb8e65ba Liu Peibao  2022-11-03  245  	struct device_node *dn, *parent = dev->of_node;
f93e71fb8e65ba Liu Peibao  2022-11-03  246  	struct mask_entry *entry;
f93e71fb8e65ba Liu Peibao  2022-11-03  247  	int devfn;
f93e71fb8e65ba Liu Peibao  2022-11-03  248  
f93e71fb8e65ba Liu Peibao  2022-11-03  249  	INIT_LIST_HEAD(&priv->masklist);
f93e71fb8e65ba Liu Peibao  2022-11-03  250  
f93e71fb8e65ba Liu Peibao  2022-11-03  251  	for_each_child_of_node(parent, dn) {
f93e71fb8e65ba Liu Peibao  2022-11-03  252  		if (of_property_read_bool(dn, "skip-scan")) {
f93e71fb8e65ba Liu Peibao  2022-11-03  253  			devfn = of_pci_get_devfn(dn);
f93e71fb8e65ba Liu Peibao  2022-11-03  254  			if (devfn < 0)
f93e71fb8e65ba Liu Peibao  2022-11-03  255  				continue;
f93e71fb8e65ba Liu Peibao  2022-11-03  256  
f93e71fb8e65ba Liu Peibao  2022-11-03 @257  			entry = devm_kzalloc(dev, sizeof(entry), GFP_KERNEL);
                                                                                          ^^^^^^^^^^^^^
Should be sizeof(*entry)

f93e71fb8e65ba Liu Peibao  2022-11-03  258  			if (!entry)
f93e71fb8e65ba Liu Peibao  2022-11-03  259  				return -ENOMEM;
f93e71fb8e65ba Liu Peibao  2022-11-03  260  
f93e71fb8e65ba Liu Peibao  2022-11-03  261  			entry->devfn = devfn;
f93e71fb8e65ba Liu Peibao  2022-11-03  262  			list_add_tail(&entry->entry, &priv->masklist);
f93e71fb8e65ba Liu Peibao  2022-11-03  263  		}
f93e71fb8e65ba Liu Peibao  2022-11-03  264  	}
f93e71fb8e65ba Liu Peibao  2022-11-03  265  
f93e71fb8e65ba Liu Peibao  2022-11-03  266  	return 0;
f93e71fb8e65ba Liu Peibao  2022-11-03  267  }
diff mbox series

Patch

diff --git a/drivers/pci/controller/pci-loongson.c b/drivers/pci/controller/pci-loongson.c
index 05c50408f13b..4b97963977c7 100644
--- a/drivers/pci/controller/pci-loongson.c
+++ b/drivers/pci/controller/pci-loongson.c
@@ -40,11 +40,21 @@  struct loongson_pci_data {
 	struct pci_ops *ops;
 };
 
+#ifdef CONFIG_OF
+struct mask_entry {
+	struct list_head entry;
+	unsigned int devfn;
+};
+#endif
+
 struct loongson_pci {
 	void __iomem *cfg0_base;
 	void __iomem *cfg1_base;
 	struct platform_device *pdev;
 	const struct loongson_pci_data *data;
+#ifdef CONFIG_OF
+	struct list_head masklist;
+#endif
 };
 
 /* Fixup wrong class code in PCIe bridges */
@@ -194,6 +204,20 @@  static void __iomem *pci_loongson_map_bus(struct pci_bus *bus,
 			return NULL;
 	}
 
+#ifdef CONFIG_OF
+	/* Don't access devices in masklist */
+	if (pci_is_root_bus(bus)) {
+		struct list_head *list;
+		struct mask_entry *entry;
+
+		list_for_each(list, &priv->masklist) {
+			entry = list_entry(list, struct mask_entry, entry);
+			if (devfn == entry->devfn)
+				return NULL;
+		}
+	}
+#endif
+
 	/* CFG0 can only access standard space */
 	if (where < PCI_CFG_SPACE_SIZE && priv->cfg0_base)
 		return cfg0_map(priv, bus, devfn, where);
@@ -206,6 +230,41 @@  static void __iomem *pci_loongson_map_bus(struct pci_bus *bus,
 }
 
 #ifdef CONFIG_OF
+/*
+ * The PCI Controller of 2k1000 could not mask devices by
+ * setting vender id & device id in configuration space
+ * header as invalid values. When there are pins shareble
+ * between the platform device and PCI device, if the
+ * platform device is preferred, we should not scan this
+ * PCI device. In the above scene, add "skip-scan" property
+ * in the device tree node of this PCI device.
+ */
+static int setup_masklist(struct loongson_pci *priv)
+{
+	struct device *dev = &priv->pdev->dev;
+	struct device_node *dn, *parent = dev->of_node;
+	struct mask_entry *entry;
+	int devfn;
+
+	INIT_LIST_HEAD(&priv->masklist);
+
+	for_each_child_of_node(parent, dn) {
+		if (of_property_read_bool(dn, "skip-scan")) {
+			devfn = of_pci_get_devfn(dn);
+			if (devfn < 0)
+				continue;
+
+			entry = devm_kzalloc(dev, sizeof(entry), GFP_KERNEL);
+			if (!entry)
+				return -ENOMEM;
+
+			entry->devfn = devfn;
+			list_add_tail(&entry->entry, &priv->masklist);
+		}
+	}
+
+	return 0;
+}
 
 static int loongson_map_irq(const struct pci_dev *dev, u8 slot, u8 pin)
 {
@@ -305,6 +364,9 @@  static int loongson_pci_probe(struct platform_device *pdev)
 		}
 	}
 
+	if (setup_masklist(priv))
+		return -ENOMEM;
+
 	bridge->sysdata = priv;
 	bridge->ops = priv->data->ops;
 	bridge->map_irq = loongson_map_irq;