soundwire: qcom: add auto enumeration support

Qualcomm SoundWire controller supports Auto Enumeration of the
devices within the IP. This patch enables support for this feature.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>

drivers/soundwire/qcom.c

@@ -57,6 +57,8 @@
 #define SWRM_CMD_FIFO_RD_FIFO_ADDR				0x318
 #define SWRM_RD_FIFO_CMD_ID_MASK				GENMASK(11, 8)
 #define SWRM_ENUMERATOR_CFG_ADDR				0x500
+#define SWRM_ENUMERATOR_SLAVE_DEV_ID_1(m)		(0x530 + 0x8 * (m))
+#define SWRM_ENUMERATOR_SLAVE_DEV_ID_2(m)		(0x534 + 0x8 * (m))
 #define SWRM_MCP_FRAME_CTRL_BANK_ADDR(m)		(0x101C + 0x40 * (m))
 #define SWRM_MCP_FRAME_CTRL_BANK_COL_CTRL_BMSK			GENMASK(2, 0)
 #define SWRM_MCP_FRAME_CTRL_BANK_ROW_CTRL_BMSK			GENMASK(7, 3)
@@ -143,6 +145,7 @@ struct qcom_swrm_ctrl {
 	enum sdw_slave_status status[SDW_MAX_DEVICES];
 	int (*reg_read)(struct qcom_swrm_ctrl *ctrl, int reg, u32 *val);
 	int (*reg_write)(struct qcom_swrm_ctrl *ctrl, int reg, int val);
+	u32 slave_status;
 };
 
 struct qcom_swrm_data {
@@ -342,6 +345,7 @@ static void qcom_swrm_get_device_status(struct qcom_swrm_ctrl *ctrl)
 	int i;
 
 	ctrl->reg_read(ctrl, SWRM_MCP_SLV_STATUS, &val);
+	ctrl->slave_status = val;
 
 	for (i = 0; i < SDW_MAX_DEVICES; i++) {
 		u32 s;
@@ -352,10 +356,74 @@ static void qcom_swrm_get_device_status(struct qcom_swrm_ctrl *ctrl)
 	}
 }
 
+static void qcom_swrm_set_slave_dev_num(struct sdw_bus *bus,
+					struct sdw_slave *slave, int devnum)
+{
+	struct qcom_swrm_ctrl *ctrl = to_qcom_sdw(bus);
+	u32 status;
+
+	ctrl->reg_read(ctrl, SWRM_MCP_SLV_STATUS, &status);
+	status = (status >> (devnum * SWRM_MCP_SLV_STATUS_SZ));
+	status &= SWRM_MCP_SLV_STATUS_MASK;
+
+	if (status == SDW_SLAVE_ATTACHED) {
+		if (slave)
+			slave->dev_num = devnum;
+		mutex_lock(&bus->bus_lock);
+		set_bit(devnum, bus->assigned);
+		mutex_unlock(&bus->bus_lock);
+	}
+}
+
+static int qcom_swrm_enumerate(struct sdw_bus *bus)
+{
+	struct qcom_swrm_ctrl *ctrl = to_qcom_sdw(bus);
+	struct sdw_slave *slave, *_s;
+	struct sdw_slave_id id;
+	u32 val1, val2;
+	bool found;
+	u64 addr;
+	int i;
+	char *buf1 = (char *)&val1, *buf2 = (char *)&val2;
+
+	for (i = 1; i <= SDW_MAX_DEVICES; i++) {
+		/*SCP_Devid5 - Devid 4*/
+		ctrl->reg_read(ctrl, SWRM_ENUMERATOR_SLAVE_DEV_ID_1(i), &val1);
+
+		/*SCP_Devid3 - DevId 2 Devid 1 Devid 0*/
+		ctrl->reg_read(ctrl, SWRM_ENUMERATOR_SLAVE_DEV_ID_2(i), &val2);
+
+		if (!val1 && !val2)
+			break;
+
+		addr = buf2[1] | (buf2[0] << 8) | (buf1[3] << 16) |
+			((u64)buf1[2] << 24) | ((u64)buf1[1] << 32) |
+			((u64)buf1[0] << 40);
+
+		sdw_extract_slave_id(bus, addr, &id);
+		found = false;
+		/* Now compare with entries */
+		list_for_each_entry_safe(slave, _s, &bus->slaves, node) {
+			if (sdw_compare_devid(slave, id) == 0) {
+				qcom_swrm_set_slave_dev_num(bus, slave, i);
+				found = true;
+				break;
+			}
+		}
+
+		if (!found) {
+			qcom_swrm_set_slave_dev_num(bus, NULL, i);
+			sdw_slave_add(bus, &id, NULL);
+		}
+	}
+
+	return 0;
+}
+
 static irqreturn_t qcom_swrm_irq_handler(int irq, void *dev_id)
 {
 	struct qcom_swrm_ctrl *swrm = dev_id;
-	u32 value, intr_sts, intr_sts_masked;
+	u32 value, intr_sts, intr_sts_masked, slave_status;
 	u32 i;
 	u8 devnum = 0;
 	int ret = IRQ_HANDLED;
@@ -384,8 +452,15 @@ static irqreturn_t qcom_swrm_irq_handler(int irq, void *dev_id)
 			case SWRM_INTERRUPT_STATUS_CHANGE_ENUM_SLAVE_STATUS:
 				dev_err_ratelimited(swrm->dev, "%s: SWR new slave attached\n",
 					__func__);
-				qcom_swrm_get_device_status(swrm);
-				sdw_handle_slave_status(&swrm->bus, swrm->status);
+				swrm->reg_read(swrm, SWRM_MCP_SLV_STATUS, &slave_status);
+				if (swrm->slave_status == slave_status) {
+					dev_err(swrm->dev, "Slave status not changed %x\n",
+						slave_status);
+				} else {
+					qcom_swrm_get_device_status(swrm);
+					qcom_swrm_enumerate(&swrm->bus);
+					sdw_handle_slave_status(&swrm->bus, swrm->status);
+				}
 				break;
 			case SWRM_INTERRUPT_STATUS_MASTER_CLASH_DET:
 				dev_err_ratelimited(swrm->dev,
@@ -472,8 +547,8 @@ static int qcom_swrm_init(struct qcom_swrm_ctrl *ctrl)
 
 	ctrl->reg_write(ctrl, SWRM_MCP_FRAME_CTRL_BANK_ADDR(0), val);
 
-	/* Disable Auto enumeration */
-	ctrl->reg_write(ctrl, SWRM_ENUMERATOR_CFG_ADDR, 0);
+	/* Enable Auto enumeration */
+	ctrl->reg_write(ctrl, SWRM_ENUMERATOR_CFG_ADDR, 1);
 
 	ctrl->intr_mask = SWRM_INTERRUPT_STATUS_RMSK;
 	/* Mask soundwire interrupts */
@@ -507,6 +582,7 @@ static int qcom_swrm_init(struct qcom_swrm_ctrl *ctrl)
 		ctrl->reg_write(ctrl, SWRM_INTERRUPT_CPU_EN,
 				SWRM_INTERRUPT_STATUS_RMSK);
 	}
+	ctrl->slave_status = 0;
 	return 0;
 }