[PATCH V4 01/18] irqchip: tegra: do not disable COP IRQ during suspend

[Sowjanya Komatineni <skomatineni@nvidia.com>]

Tegra210 platforms use sc7 entry firmware to program Tegra LP0/SC7 entry
sequence and sc7 entry firmware is run from COP/BPMP-Lite.

So, COP/BPMP-Lite still need IRQ function to finish SC7 suspend sequence
for Tegra210.

This patch has fix for leaving the COP IRQ enabled for Tegra210 during
interrupt controller suspend operation.

Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com>
---
 drivers/irqchip/irq-tegra.c | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/drivers/irqchip/irq-tegra.c b/drivers/irqchip/irq-tegra.c
index e1f771c72fc4..851f88cef508 100644
--- a/drivers/irqchip/irq-tegra.c
+++ b/drivers/irqchip/irq-tegra.c
@@ -44,6 +44,7 @@ static unsigned int num_ictlrs;
 
 struct tegra_ictlr_soc {
 	unsigned int num_ictlrs;
+	bool supports_sc7;
 };
 
 static const struct tegra_ictlr_soc tegra20_ictlr_soc = {
@@ -56,6 +57,7 @@ static const struct tegra_ictlr_soc tegra30_ictlr_soc = {
 
 static const struct tegra_ictlr_soc tegra210_ictlr_soc = {
 	.num_ictlrs = 6,
+	.supports_sc7 = true,
 };
 
 static const struct of_device_id ictlr_matches[] = {
@@ -67,6 +69,7 @@ static const struct of_device_id ictlr_matches[] = {
 
 struct tegra_ictlr_info {
 	void __iomem *base[TEGRA_MAX_NUM_ICTLRS];
+	const struct tegra_ictlr_soc *soc;
 #ifdef CONFIG_PM_SLEEP
 	u32 cop_ier[TEGRA_MAX_NUM_ICTLRS];
 	u32 cop_iep[TEGRA_MAX_NUM_ICTLRS];
@@ -147,8 +150,20 @@ static int tegra_ictlr_suspend(void)
 		lic->cop_ier[i] = readl_relaxed(ictlr + ICTLR_COP_IER);
 		lic->cop_iep[i] = readl_relaxed(ictlr + ICTLR_COP_IEP_CLASS);
 
-		/* Disable COP interrupts */
-		writel_relaxed(~0ul, ictlr + ICTLR_COP_IER_CLR);
+		/*
+		 * AVP/COP/BPMP-Lite is the Tegra boot processor.
+		 *
+		 * Tegra210 system suspend flow uses sc7entry firmware which
+		 * is executed by COP/BPMP and it includes disabling COP IRQ,
+		 * clamping CPU rail, turning off VDD_CPU, and preparing the
+		 * system to go to SC7/LP0.
+		 *
+		 * COP/BPMP wakes up when COP IRQ is triggered and runs
+		 * sc7entry-firmware. So need to keep COP interrupt enabled.
+		 */
+		if (!lic->soc->supports_sc7)
+			/* Disable COP interrupts if SC7 is not supported */
+			writel_relaxed(~0ul, ictlr + ICTLR_COP_IER_CLR);
 
 		/* Disable CPU interrupts */
 		writel_relaxed(~0ul, ictlr + ICTLR_CPU_IER_CLR);
@@ -339,6 +354,7 @@ static int __init tegra_ictlr_init(struct device_node *node,
 		goto out_unmap;
 	}
 
+	lic->soc = soc;
 	tegra_ictlr_syscore_init();
 
 	pr_info("%pOF: %d interrupts forwarded to %pOF\n",
-- 
2.7.4