[PATCH v4 3/3] wifi: ath10k: only load compatible DT cal data

[equu@openmail.cc]

From: Edward Chow <equu@openmail.cc>

ath10k might also be sensitive to the issue reported on
https://github.com/openwrt/openwrt/pull/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>
Reported-by: kernel test robot <lkp@intel.com>
---
 drivers/net/wireless/ath/ath10k/core.c | 29 ++++++++++++++++++++++++++
 drivers/net/wireless/ath/ath10k/pci.c  |  2 +-
 drivers/net/wireless/ath/ath10k/pci.h  |  2 ++
 3 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/ath/ath10k/core.c b/drivers/net/wireless/ath/ath10k/core.c
index 5eb131ab916f..a1cf65679046 100644
--- a/drivers/net/wireless/ath/ath10k/core.c
+++ b/drivers/net/wireless/ath/ath10k/core.c
@@ -13,6 +13,7 @@
 #include <linux/ctype.h>
 #include <linux/pm_qos.h>
 #include <linux/nvmem-consumer.h>
+#include <linux/of_pci.h>
 #include <asm/byteorder.h>
 
 #include "core.h"
@@ -26,6 +27,7 @@
 #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 +1960,33 @@ 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 ath10k 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_driver(ar->dev->of_node,
+				       &ath10k_pci_driver)))
+		return -ENOENT;
+
 	cell = devm_nvmem_cell_get(ar->dev, cell_name);
 	if (IS_ERR(cell)) {
 		ret = PTR_ERR(cell);
diff --git a/drivers/net/wireless/ath/ath10k/pci.c b/drivers/net/wireless/ath/ath10k/pci.c
index 728d607289c3..5d9f6046f8cf 100644
--- a/drivers/net/wireless/ath/ath10k/pci.c
+++ b/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,
diff --git a/drivers/net/wireless/ath/ath10k/pci.h b/drivers/net/wireless/ath/ath10k/pci.h
index 480cd97ab739..de676797b736 100644
--- a/drivers/net/wireless/ath/ath10k/pci.h
+++ b/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);
-- 
2.39.1