platform/x86: intel_scu_ipc: Fix interrupt support

commit e48b72a5 upstream.

Currently the driver has disabled interrupt support for Tangier but
actually interrupt works just fine if the command is not written twice
in a row. Also we need to ack the interrupt in the handler.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/platform/x86/intel_scu_ipc.c

@@ -69,26 +69,22 @@
 struct intel_scu_ipc_pdata_t {
 	u32 i2c_base;
 	u32 i2c_len;
-	u8 irq_mode;
 };
 
 static const struct intel_scu_ipc_pdata_t intel_scu_ipc_lincroft_pdata = {
 	.i2c_base = 0xff12b000,
 	.i2c_len = 0x10,
-	.irq_mode = 0,
 };
 
 /* Penwell and Cloverview */
 static const struct intel_scu_ipc_pdata_t intel_scu_ipc_penwell_pdata = {
 	.i2c_base = 0xff12b000,
 	.i2c_len = 0x10,
-	.irq_mode = 1,
 };
 
 static const struct intel_scu_ipc_pdata_t intel_scu_ipc_tangier_pdata = {
 	.i2c_base  = 0xff00d000,
 	.i2c_len = 0x10,
-	.irq_mode = 0,
 };
 
 struct intel_scu_ipc_dev {
@@ -101,6 +97,9 @@ struct intel_scu_ipc_dev {
 
 static struct intel_scu_ipc_dev  ipcdev; /* Only one for now */
 
+#define IPC_STATUS		0x04
+#define IPC_STATUS_IRQ		BIT(2)
+
 /*
  * IPC Read Buffer (Read Only):
  * 16 byte buffer for receiving data from SCU, if IPC command
@@ -122,11 +121,8 @@ static DEFINE_MUTEX(ipclock); /* lock used to prevent multiple call to SCU */
  */
 static inline void ipc_command(struct intel_scu_ipc_dev *scu, u32 cmd)
 {
-	if (scu->irq_mode) {
 	reinit_completion(&scu->cmd_complete);
 	writel(cmd | IPC_IOC, scu->ipc_base);
-	}
-	writel(cmd, scu->ipc_base);
 }
 
 /*
@@ -612,8 +608,9 @@ EXPORT_SYMBOL(intel_scu_ipc_i2c_cntrl);
 static irqreturn_t ioc(int irq, void *dev_id)
 {
 	struct intel_scu_ipc_dev *scu = dev_id;
+	int status = ipc_read_status(scu);
 
-	if (scu->irq_mode)
+	writel(status | IPC_STATUS_IRQ, scu->ipc_base + IPC_STATUS);
 	complete(&scu->cmd_complete);
 
 	return IRQ_HANDLED;
@@ -640,8 +637,6 @@ static int ipc_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 	if (!pdata)
 		return -ENODEV;
 
-	scu->irq_mode = pdata->irq_mode;
-
 	err = pcim_enable_device(pdev);
 	if (err)
 		return err;