[PATCH 349/379][SRU][OEM-5.6] bus: mhi: core: Allow shared IRQ for event rings

[You-Sheng Yang]

From: Loic Poulain <loic.poulain at linaro.org>

BugLink: https://bugs.launchpad.net/bugs/1879633

There is no requirement for using a dedicated IRQ per event ring.
Some systems does not support multiple MSI vectors (e.g. intel
without CONFIG_IRQ_REMAP), In that case the MHI controller can
configure all the event rings to use the same interrupt (as fallback).

Allow this by removing the nr_irqs = ev_ring test and add extra check
in the irq_setup function.

Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam at linaro.org>
Signed-off-by: Loic Poulain <loic.poulain at linaro.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam at linaro.org>
Link: https://lore.kernel.org/r/20200929175218.8178-17-manivannan.sadhasivam@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
(cherry picked from commit b0fc0167f25401a5dd0325a935e3a20d1da2aa0b)
Signed-off-by: You-Sheng Yang <vicamo.yang at canonical.com>
---
 drivers/bus/mhi/core/init.c | 7 +++++++
 drivers/bus/mhi/core/pm.c   | 2 +-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c
index a33665b7ee54..103d51f35e28 100644
--- a/drivers/bus/mhi/core/init.c
+++ b/drivers/bus/mhi/core/init.c
@@ -162,6 +162,13 @@ int mhi_init_irq_setup(struct mhi_controller *mhi_cntrl)
 		if (mhi_event->offload_ev)
 			continue;
 
+		if (mhi_event->irq >= mhi_cntrl->nr_irqs) {
+			dev_err(dev, "irq %d not available for event ring\n",
+				mhi_event->irq);
+			ret = -EINVAL;
+			goto error_request;
+		}
+
 		ret = request_irq(mhi_cntrl->irq[mhi_event->irq],
 				  mhi_irq_handler,
 				  IRQF_SHARED | IRQF_NO_SUSPEND,
diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c
index ce4d969818b4..3de7b1639ec6 100644
--- a/drivers/bus/mhi/core/pm.c
+++ b/drivers/bus/mhi/core/pm.c
@@ -918,7 +918,7 @@ int mhi_async_power_up(struct mhi_controller *mhi_cntrl)
 
 	dev_info(dev, "Requested to power ON\n");
 
-	if (mhi_cntrl->nr_irqs < mhi_cntrl->total_ev_rings)
+	if (mhi_cntrl->nr_irqs < 1)
 		return -EINVAL;
 
 	/* Supply default wake routines if not provided by controller driver */
-- 
2.29.2