ath9k: add new function ath9k_hw_read_array

REG_READ generate most overhead on usb bus. It send and read micro packages
and reduce usb bandwidth. To reduce this overhead we should read in batches.
Signed-off-by: Oleksij Rempel <linux@rempel-privat.de>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/ath/ath9k/hw.c

@@ -121,6 +121,36 @@ void ath9k_hw_write_array(struct ath_hw *ah, const struct ar5416IniArray *array,
 	REGWRITE_BUFFER_FLUSH(ah);
 }
 
+void ath9k_hw_read_array(struct ath_hw *ah, u32 array[][2], int size)
+{
+	u32 *tmp_reg_list, *tmp_data;
+	int i;
+
+	tmp_reg_list = kmalloc(size * sizeof(u32), GFP_KERNEL);
+	if (!tmp_reg_list) {
+		dev_err(ah->dev, "%s: tmp_reg_list: alloc filed\n", __func__);
+		return;
+	}
+
+	tmp_data = kmalloc(size * sizeof(u32), GFP_KERNEL);
+	if (!tmp_data) {
+		dev_err(ah->dev, "%s tmp_data: alloc filed\n", __func__);
+		goto error_tmp_data;
+	}
+
+	for (i = 0; i < size; i++)
+		tmp_reg_list[i] = array[i][0];
+
+	REG_READ_MULTI(ah, tmp_reg_list, tmp_data, size);
+
+	for (i = 0; i < size; i++)
+		array[i][1] = tmp_data[i];
+
+	kfree(tmp_data);
+error_tmp_data:
+	kfree(tmp_reg_list);
+}
+
 u32 ath9k_hw_reverse_bits(u32 val, u32 n)
 {
 	u32 retval;

drivers/net/wireless/ath/ath9k/hw.h

@@ -138,6 +138,8 @@
 
 #define REG_WRITE_ARRAY(iniarray, column, regWr) \
 	ath9k_hw_write_array(ah, iniarray, column, &(regWr))
+#define REG_READ_ARRAY(ah, array, size) \
+	ath9k_hw_read_array(ah, array, size)
 
 #define AR_GPIO_OUTPUT_MUX_AS_OUTPUT             0
 #define AR_GPIO_OUTPUT_MUX_AS_PCIE_ATTENTION_LED 1
@@ -1030,6 +1032,7 @@ void ath9k_hw_synth_delay(struct ath_hw *ah, struct ath9k_channel *chan,
 bool ath9k_hw_wait(struct ath_hw *ah, u32 reg, u32 mask, u32 val, u32 timeout);
 void ath9k_hw_write_array(struct ath_hw *ah, const struct ar5416IniArray *array,
 			  int column, unsigned int *writecnt);
+void ath9k_hw_read_array(struct ath_hw *ah, u32 array[][2], int size);
 u32 ath9k_hw_reverse_bits(u32 val, u32 n);
 u16 ath9k_hw_computetxtime(struct ath_hw *ah,
 			   u8 phy, int kbps,