wifi: ath10k: only load compatible DT cal data

ath10k might also be sensitive to the issue reported on
openwrt/openwrt#11345 , loading calibration
data from a device tree node declared incompatible.

ath10k will first check whether the device tree node is compatible
with it, using the functionality introduced with the first patch of
this series, ("PCI: of: Match pci devices or drivers against OF DT
nodes") and only proceed loading calibration data from compatible node.

Signed-off-by: Edward Chow <equu@openmail.cc>

drivers/net/wireless/ath/ath10k/core.c

@@ -26,6 +26,7 @@
 #include "testmode.h"
 #include "wmi-ops.h"
 #include "coredump.h"
+#include "pci.h"
 
 unsigned int ath10k_debug_mask;
 EXPORT_SYMBOL(ath10k_debug_mask);
@@ -1958,6 +1959,33 @@ static int ath10k_download_cal_nvmem(struct ath10k *ar, const char *cell_name)
 	size_t len;
 	int ret;
 
+	/* devm_nvmem_cell_get() will get a cell first from the OF
+	 * DT node representing the given device with nvmem-cell-name
+	 * "calibration", and from the global lookup table as a fallback,
+	 * and an ath9k device could be either a pci one or a platform one.
+	 *
+	 * If the OF DT node is not compatible with the real device, the
+	 * calibration data got from the node should not be applied.
+	 *
+	 * dev_is_pci(ar->dev) && ( no OF node || caldata not from node
+	 * || not compatible ) -> do not use caldata .
+	 *
+	 * !dev_is_pci(ar->dev) -> always use caldata .
+	 *
+	 * The judgement for compatibility differs with ath9k for many
+	 * DT using "qcom,ath10k" as compatibility string.
+	 */
+	if (dev_is_pci(ar->dev) &&
+	    (!ar->dev->of_node ||
+	     (of_property_match_string(ar->dev->of_node,
+				       "nvmem-cell-names",
+				       cell_name) < 0) ||
+	     !of_device_is_compatible(ar->dev->of_node,
+				      "qcom,ath10k") ||
+	     !of_pci_node_match_device(ar->dev->of_node,
+				       &ath10k_pci_driver)))
+		return ERR_PTR(-ENOENT);
+
 	cell = devm_nvmem_cell_get(ar->dev, cell_name);
 	if (IS_ERR(cell)) {
 		ret = PTR_ERR(cell);

drivers/net/wireless/ath/ath10k/pci.c

@@ -3780,7 +3780,7 @@ static SIMPLE_DEV_PM_OPS(ath10k_pci_pm_ops,
 			 ath10k_pci_pm_suspend,
 			 ath10k_pci_pm_resume);
 
-static struct pci_driver ath10k_pci_driver = {
+struct pci_driver ath10k_pci_driver = {
 	.name = "ath10k_pci",
 	.id_table = ath10k_pci_id_table,
 	.probe = ath10k_pci_probe,

drivers/net/wireless/ath/ath10k/pci.h

@@ -209,6 +209,8 @@ static inline struct ath10k_pci *ath10k_pci_priv(struct ath10k *ar)
 #define DIAG_ACCESS_CE_TIMEOUT_US 10000 /* 10 ms */
 #define DIAG_ACCESS_CE_WAIT_US	50
 
+extern struct pci_driver ath10k_pci_driver;
+
 void ath10k_pci_write32(struct ath10k *ar, u32 offset, u32 value);
 void ath10k_pci_soc_write32(struct ath10k *ar, u32 addr, u32 val);
 void ath10k_pci_reg_write32(struct ath10k *ar, u32 addr, u32 val);