iwlagn: introduce struct iwl-shared - known by all layers

This struct will hold pointers to all the layers, so that every layer will find
the pointers it needs when calling another layer.

Note that the drv_data set to struct device is now a pointer to
struct iwl_shared.
This solves of bug that I introduced in

	iwlagn: simplify the bus architecture

Bug description:

sysfs gets the the driver data from struct device. Till the aforementioned
patch, dev_get_drvdata would return iwl_priv. After the patch, dev_get_drvdata
return iwl_bus which is buggy since the sysfs handlers rely on this value, and
sysfs handlers need iwl_priv.

Now, dev_get_drvdata return iwl-shared. Since we have pointers to all the
layers in iwl_shared, every layer will be able to get the pointer it needs:
bus layer will gets iwl_bus from the PCI suspend callbacks, and the sysfs
handlers will get the iwl_priv they need.

In order to keep good encapsulation, we need to avoid to dereference iwl_priv
from a different layer. This is why instead of including iwl-dev.h from
iwl-shared.h, I added a forward declaration to iwl_priv. Moreover we keep type
safety while providing encapsulation.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/iwlwifi/iwl-agn.c

@@ -473,14 +473,15 @@ static void iwl_bg_tx_flush(struct work_struct *work)
 static ssize_t show_debug_level(struct device *d,
 				struct device_attribute *attr, char *buf)
 {
-	struct iwl_priv *priv = dev_get_drvdata(d);
-	return sprintf(buf, "0x%08X\n", iwl_get_debug_level(priv));
+	struct iwl_shared *shrd = dev_get_drvdata(d);
+	return sprintf(buf, "0x%08X\n", iwl_get_debug_level(shrd->priv));
 }
 static ssize_t store_debug_level(struct device *d,
 				struct device_attribute *attr,
 				 const char *buf, size_t count)
 {
-	struct iwl_priv *priv = dev_get_drvdata(d);
+	struct iwl_shared *shrd = dev_get_drvdata(d);
+	struct iwl_priv *priv = shrd->priv;
 	unsigned long val;
 	int ret;
 
@@ -506,7 +507,8 @@ static DEVICE_ATTR(debug_level, S_IWUSR | S_IRUGO,
 static ssize_t show_temperature(struct device *d,
 				struct device_attribute *attr, char *buf)
 {
-	struct iwl_priv *priv = dev_get_drvdata(d);
+	struct iwl_shared *shrd = dev_get_drvdata(d);
+	struct iwl_priv *priv = shrd->priv;
 
 	if (!iwl_is_alive(priv))
 		return -EAGAIN;
@@ -3603,7 +3605,10 @@ int iwl_probe(struct iwl_bus *bus, struct iwl_cfg *cfg)
 
 	priv = hw->priv;
 	priv->bus = bus;
-	bus_set_drv_data(priv->bus, priv);
+	priv->shrd = &priv->_shrd;
+	priv->shrd->bus = bus;
+	priv->shrd->priv = priv;
+	bus_set_drv_data(priv->bus, priv->shrd);
 
 	/* At this point both hw and priv are allocated. */
 

drivers/net/wireless/iwlwifi/iwl-bus.h

@@ -63,13 +63,14 @@
 #ifndef __iwl_pci_h__
 #define __iwl_pci_h__
 
+struct iwl_shared;
 struct iwl_bus;
 
 /**
  * struct iwl_bus_ops - bus specific operations
  * @get_pm_support: must returns true if the bus can go to sleep
  * @apm_config: will be called during the config of the APM configuration
- * @set_drv_data: set the drv_data pointer to the bus layer
+ * @set_drv_data: set the shared data pointer to the bus layer
  * @get_hw_id: prints the hw_id in the provided buffer
  * @write8: write a byte to register at offset ofs
  * @write32: write a dword to register at offset ofs
@@ -78,7 +79,7 @@ struct iwl_bus;
 struct iwl_bus_ops {
 	bool (*get_pm_support)(struct iwl_bus *bus);
 	void (*apm_config)(struct iwl_bus *bus);
-	void (*set_drv_data)(struct iwl_bus *bus, void *drv_data);
+	void (*set_drv_data)(struct iwl_bus *bus, struct iwl_shared *shrd);
 	void (*get_hw_id)(struct iwl_bus *bus, char buf[], int buf_len);
 	void (*write8)(struct iwl_bus *bus, u32 ofs, u8 val);
 	void (*write32)(struct iwl_bus *bus, u32 ofs, u32 val);
@@ -87,9 +88,9 @@ struct iwl_bus_ops {
 
 struct iwl_bus {
 	/* Common data to all buses */
-	void *drv_data; /* driver's context */
 	struct device *dev;
 	struct iwl_bus_ops *ops;
+	struct iwl_shared *shrd;
 
 	unsigned int irq;
 
@@ -108,9 +109,10 @@ static inline void bus_apm_config(struct iwl_bus *bus)
 	bus->ops->apm_config(bus);
 }
 
-static inline void bus_set_drv_data(struct iwl_bus *bus, void *drv_data)
+static inline void bus_set_drv_data(struct iwl_bus *bus,
+				struct iwl_shared *shrd)
 {
-	bus->ops->set_drv_data(bus, drv_data);
+	bus->ops->set_drv_data(bus, shrd);
 }
 
 static inline void bus_get_hw_id(struct iwl_bus *bus, char buf[], int buf_len)

drivers/net/wireless/iwlwifi/iwl-dev.h

@@ -1210,6 +1210,10 @@ struct iwl_testmode_trace {
 
 struct iwl_priv {
 
+	/*data shared among all the driver's layers */
+	struct iwl_shared _shrd;
+	struct iwl_shared *shrd;
+
 	/* ieee device used by generic ieee processing code */
 	struct ieee80211_hw *hw;
 	struct ieee80211_channel *ieee_channels;

drivers/net/wireless/iwlwifi/iwl-pci.c

@@ -123,21 +123,21 @@ static void iwl_pci_apm_config(struct iwl_bus *bus)
 	if ((lctl & PCI_CFG_LINK_CTRL_VAL_L1_EN) ==
 				PCI_CFG_LINK_CTRL_VAL_L1_EN) {
 		/* L1-ASPM enabled; disable(!) L0S */
-		iwl_set_bit(bus->drv_data, CSR_GIO_REG,
+		iwl_set_bit(priv(bus), CSR_GIO_REG,
 				CSR_GIO_REG_VAL_L0S_ENABLED);
 		dev_printk(KERN_INFO, bus->dev, "L1 Enabled; Disabling L0S\n");
 	} else {
 		/* L1-ASPM disabled; enable(!) L0S */
-		iwl_clear_bit(bus->drv_data, CSR_GIO_REG,
+		iwl_clear_bit(priv(bus), CSR_GIO_REG,
 				CSR_GIO_REG_VAL_L0S_ENABLED);
 		dev_printk(KERN_INFO, bus->dev, "L1 Disabled; Enabling L0S\n");
 	}
 }
 
-static void iwl_pci_set_drv_data(struct iwl_bus *bus, void *drv_data)
+static void iwl_pci_set_drv_data(struct iwl_bus *bus, struct iwl_shared *shrd)
 {
-	bus->drv_data = drv_data;
-	pci_set_drvdata(IWL_BUS_GET_PCI_DEV(bus), drv_data);
+	bus->shrd = shrd;
+	pci_set_drvdata(IWL_BUS_GET_PCI_DEV(bus), shrd);
 }
 
 static void iwl_pci_get_hw_id(struct iwl_bus *bus, char buf[],
@@ -496,33 +496,33 @@ static void iwl_pci_down(struct iwl_bus *bus)
 
 static void __devexit iwl_pci_remove(struct pci_dev *pdev)
 {
-	struct iwl_priv *priv = pci_get_drvdata(pdev);
-	void *bus_specific = priv->bus->bus_specific;
+	struct iwl_shared *shrd = pci_get_drvdata(pdev);
+	struct iwl_bus *bus = shrd->bus;
 
-	iwl_remove(priv);
+	iwl_remove(shrd->priv);
 
-	iwl_pci_down(bus_specific);
+	iwl_pci_down(bus);
 }
 
 #ifdef CONFIG_PM
 
 static int iwl_pci_suspend(struct device *device)
 {
 	struct pci_dev *pdev = to_pci_dev(device);
-	struct iwl_priv *priv = pci_get_drvdata(pdev);
+	struct iwl_shared *shrd = pci_get_drvdata(pdev);
 
 	/* Before you put code here, think about WoWLAN. You cannot check here
 	 * whether WoWLAN is enabled or not, and your code will run even if
 	 * WoWLAN is enabled - don't kill the NIC, someone may need it in Sx.
 	 */
 
-	return iwl_suspend(priv);
+	return iwl_suspend(shrd->priv);
 }
 
 static int iwl_pci_resume(struct device *device)
 {
 	struct pci_dev *pdev = to_pci_dev(device);
-	struct iwl_priv *priv = pci_get_drvdata(pdev);
+	struct iwl_shared *shrd = pci_get_drvdata(pdev);
 
 	/* Before you put code here, think about WoWLAN. You cannot check here
 	 * whether WoWLAN is enabled or not, and your code will run even if
@@ -535,7 +535,7 @@ static int iwl_pci_resume(struct device *device)
 	 */
 	pci_write_config_byte(pdev, PCI_CFG_RETRY_TIMEOUT, 0x00);
 
-	return iwl_resume(priv);
+	return iwl_resume(shrd->priv);
 }
 
 static SIMPLE_DEV_PM_OPS(iwl_dev_pm_ops, iwl_pci_suspend, iwl_pci_resume);

drivers/net/wireless/iwlwifi/iwl-shared.h

@@ -64,6 +64,7 @@
 #define __iwl_shared_h__
 
 struct iwl_cfg;
+struct iwl_bus;
 struct iwl_priv;
 
 extern struct iwl_mod_params iwlagn_mod_params;
@@ -89,6 +90,21 @@ struct iwl_mod_params {
 	int wanted_ucode_alternative;
 };
 
+/**
+ * struct iwl_shared - shared fields for all the layers of the driver
+ *
+ * @bus: pointer to the bus layer data
+ * @priv: pointer to the upper layer data
+ */
+struct iwl_shared {
+	struct iwl_bus *bus;
+	struct iwl_priv *priv;
+};
+
+/*Whatever _m is (iwl_trans, iwl_priv, iwl_bus, these macros will work */
+#define priv(_m)	((_m)->shrd->priv)
+#define bus(_m)		((_m)->shrd->bus)
+
 #ifdef CONFIG_PM
 int iwl_suspend(struct iwl_priv *priv);
 int iwl_resume(struct iwl_priv *priv);