Bluetooth: btmrvl: implement read-to-clear for SD8897 interrupts

For SD8897, CMD52 write_to_clear may have missing interrupts
under certain corner case condition. Use CMD53 read-to-clear
to fix the problem.

Signed-off-by: Bing Zhao <bzhao@marvell.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
diff --git a/drivers/bluetooth/btmrvl_sdio.c b/drivers/bluetooth/btmrvl_sdio.c
index 7883793..9dedca5 100644
--- a/drivers/bluetooth/btmrvl_sdio.c
+++ b/drivers/bluetooth/btmrvl_sdio.c
@@ -64,6 +64,7 @@
 	.io_port_0 = 0x00,
 	.io_port_1 = 0x01,
 	.io_port_2 = 0x02,
+	.int_read_to_clear = false,
 };
 static const struct btmrvl_sdio_card_reg btmrvl_reg_87xx = {
 	.cfg = 0x00,
@@ -80,6 +81,7 @@
 	.io_port_0 = 0x78,
 	.io_port_1 = 0x79,
 	.io_port_2 = 0x7a,
+	.int_read_to_clear = false,
 };
 
 static const struct btmrvl_sdio_card_reg btmrvl_reg_88xx = {
@@ -97,6 +99,9 @@
 	.io_port_0 = 0xd8,
 	.io_port_1 = 0xd9,
 	.io_port_2 = 0xda,
+	.int_read_to_clear = true,
+	.host_int_rsr = 0x01,
+	.card_misc_cfg = 0xcc,
 };
 
 static const struct btmrvl_sdio_device btmrvl_sdio_sd8688 = {
@@ -667,6 +672,23 @@
 	return 0;
 }
 
+static int btmrvl_sdio_read_to_clear(struct btmrvl_sdio_card *card, u8 *ireg)
+{
+	struct btmrvl_adapter *adapter = card->priv->adapter;
+	int ret;
+
+	ret = sdio_readsb(card->func, adapter->hw_regs, 0, SDIO_BLOCK_SIZE);
+	if (ret) {
+		BT_ERR("sdio_readsb: read int hw_regs failed: %d", ret);
+		return ret;
+	}
+
+	*ireg = adapter->hw_regs[card->reg->host_intstatus];
+	BT_DBG("hw_regs[%#x]=%#x", card->reg->host_intstatus, *ireg);
+
+	return 0;
+}
+
 static int btmrvl_sdio_write_to_clear(struct btmrvl_sdio_card *card, u8 *ireg)
 {
 	int ret;
@@ -714,7 +736,11 @@
 
 	priv = card->priv;
 
-	ret = btmrvl_sdio_write_to_clear(card, &ireg);
+	if (card->reg->int_read_to_clear)
+		ret = btmrvl_sdio_read_to_clear(card, &ireg);
+	else
+		ret = btmrvl_sdio_write_to_clear(card, &ireg);
+
 	if (ret)
 		return;
 
@@ -788,6 +814,30 @@
 
 	BT_DBG("SDIO FUNC%d IO port: 0x%x", func->num, card->ioport);
 
+	if (card->reg->int_read_to_clear) {
+		reg = sdio_readb(func, card->reg->host_int_rsr, &ret);
+		if (ret < 0) {
+			ret = -EIO;
+			goto release_irq;
+		}
+		sdio_writeb(func, reg | 0x3f, card->reg->host_int_rsr, &ret);
+		if (ret < 0) {
+			ret = -EIO;
+			goto release_irq;
+		}
+
+		reg = sdio_readb(func, card->reg->card_misc_cfg, &ret);
+		if (ret < 0) {
+			ret = -EIO;
+			goto release_irq;
+		}
+		sdio_writeb(func, reg | 0x10, card->reg->card_misc_cfg, &ret);
+		if (ret < 0) {
+			ret = -EIO;
+			goto release_irq;
+		}
+	}
+
 	sdio_set_drvdata(func, card);
 
 	sdio_release_host(func);