Bootloader and firmware for SM8650 and older chipsets expect node
name as "qcom_scm", in order to patch the wait queue IRQ information.
However, DeviceTree uses node name "scm" and this mismatch prevents
firmware from correctly identifying waitqueue IRQ information. Waitqueue
IRQ is used for signaling between secure and non-secure worlds.

To resolve this, introduce qcom_scm_get_waitq_irq() that'll get the
hardware IRQ number to be used from firmware instead of relying on data
provided by devicetree, thereby bypassing the DeviceTree node name
mismatch.

This hardware IRQ number is converted to a Linux IRQ number using newly
defined fill_irq_fwspec_params(). This Linux IRQ number is then supplied
to the threaded_irq call.

Signed-off-by: Unnathi Chalicheemala <quic_uchalich@quicinc.com>
---
 drivers/firmware/qcom/qcom_scm.c | 54 +++++++++++++++++++++++++++++++-
 drivers/firmware/qcom/qcom_scm.h |  1 +
 2 files changed, 54 insertions(+), 1 deletion(-)

diff --git a/drivers/firmware/qcom/qcom_scm.c b/drivers/firmware/qcom/qcom_scm.c
index 10986cb11ec0..4cffd0684b78 100644
--- a/drivers/firmware/qcom/qcom_scm.c
+++ b/drivers/firmware/qcom/qcom_scm.c
@@ -35,6 +35,14 @@
 
 static u32 download_mode;
 
+#define GIC_SPI_BASE        32
+#define GIC_MAX_SPI       1019  // SPIs in GICv3 spec range from 32..1019
+#define GIC_ESPI_BASE     4096
+#define GIC_MAX_ESPI      5119 // ESPIs in GICv3 spec range from 4096..5119
+
+#define GIC_IRQ_TYPE_SPI     0
+#define GIC_IRQ_TYPE_ESPI    2
+
 struct qcom_scm {
 	struct device *dev;
 	struct clk *core_clk;
@@ -1830,6 +1838,50 @@ bool qcom_scm_is_available(void)
 }
 EXPORT_SYMBOL_GPL(qcom_scm_is_available);
 
+static int qcom_scm_fill_irq_fwspec_params(struct irq_fwspec *fwspec, u32 virq)
+{
+	if (virq >= GIC_SPI_BASE && virq <= GIC_MAX_SPI) {
+		fwspec->param[0] = GIC_IRQ_TYPE_SPI;
+		fwspec->param[1] = virq - GIC_SPI_BASE;
+	} else if (virq >= GIC_ESPI_BASE && virq <= GIC_MAX_ESPI) {
+		fwspec->param[0] = GIC_IRQ_TYPE_ESPI;
+		fwspec->param[1] = virq - GIC_ESPI_BASE;
+	} else {
+		WARN(1, "Unexpected virq: %d\n", virq);
+		return -ENXIO;
+	}
+	fwspec->param[2] = IRQ_TYPE_EDGE_RISING;
+	fwspec->param_count = 3;
+
+	return 0;
+}
+
+static int qcom_scm_get_waitq_irq(void)
+{
+	int ret;
+	u32 hwirq;
+	struct qcom_scm_desc desc = {
+		.svc = QCOM_SCM_SVC_WAITQ,
+		.cmd = QCOM_SCM_WAITQ_GET_INFO,
+		.owner = ARM_SMCCC_OWNER_SIP
+	};
+	struct qcom_scm_res res;
+	struct irq_fwspec fwspec;
+
+	ret = qcom_scm_call_atomic(__scm->dev, &desc, &res);
+	if (ret)
+		return ret;
+
+	fwspec.fwnode = of_node_to_fwnode(__scm->dev->of_node);
+	hwirq = res.result[1] & GENMASK(15, 0);
+	ret = qcom_scm_fill_irq_fwspec_params(&fwspec, hwirq);
+	if (ret)
+		return ret;
+	ret = irq_create_fwspec_mapping(&fwspec);
+
+	return ret;
+}
+
 static int qcom_scm_assert_valid_wq_ctx(u32 wq_ctx)
 {
 	/* FW currently only supports a single wq_ctx (zero).
@@ -1986,7 +2038,7 @@ static int qcom_scm_probe(struct platform_device *pdev)
 	/* Let all above stores be available after this */
 	smp_store_release(&__scm, scm);
 
-	irq = platform_get_irq_optional(pdev, 0);
+	irq = qcom_scm_get_waitq_irq();
 	if (irq < 0) {
 		if (irq != -ENXIO)
 			return irq;
diff --git a/drivers/firmware/qcom/qcom_scm.h b/drivers/firmware/qcom/qcom_scm.h
index 685b8f59e7a6..ab0f88f5f777 100644
--- a/drivers/firmware/qcom/qcom_scm.h
+++ b/drivers/firmware/qcom/qcom_scm.h
@@ -143,6 +143,7 @@ struct qcom_tzmem_pool *qcom_scm_get_tzmem_pool(void);
 #define QCOM_SCM_SVC_WAITQ			0x24
 #define QCOM_SCM_WAITQ_RESUME			0x02
 #define QCOM_SCM_WAITQ_GET_WQ_CTX		0x03
+#define QCOM_SCM_WAITQ_GET_INFO		0x04
 
 #define QCOM_SCM_SVC_GPU			0x28
 #define QCOM_SCM_SVC_GPU_INIT_REGS		0x01
-- 
2.34.1