[3.16.y-ckt stable] Patch "bus: omap_l3_noc: Add resume hook to restore context" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    bus: omap_l3_noc: Add resume hook to restore context

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt6.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From b3092dc8a6420cec3c57a518dfef6857e429a8c1 Mon Sep 17 00:00:00 2001
From: Keerthy <j-keerthy at ti.com>
Date: Mon, 10 Nov 2014 23:49:47 +0530
Subject: bus: omap_l3_noc: Add resume hook to restore context

commit 61b43d4e919e8fa5e10c77ee32ba328da07e0264 upstream.

On certain SoCs such as AM437x SoC, L3_noc error registers are
maintained in power domain such as per domain which looses context as part
of low power state such as RTC+DDR mode. On these platforms when we
mask interrupts which we cannot handle, the source of these interrupts
still remain on resume, however, the flag mux registers now contain
their reset value (unmasked) - this breaks the system with infinite
interrupts since we do not these interrupts to take place ever again.

To handle this: restore the masking of interrupts which we have
already recorded in the system as ones we cannot handle.

Fixes: 2100b595b7 ("bus: omap_l3_noc: ignore masked out unclearable targets")
Acked-by: Nishanth Menon <nm at ti.com>
Signed-off-by: Keerthy <j-keerthy at ti.com>
Signed-off-by: Tony Lindgren <tony at atomide.com>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/bus/omap_l3_noc.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)

diff --git a/drivers/bus/omap_l3_noc.c b/drivers/bus/omap_l3_noc.c
index 531ae591783b..b5eac29d8f6e 100644
--- a/drivers/bus/omap_l3_noc.c
+++ b/drivers/bus/omap_l3_noc.c
@@ -296,11 +296,66 @@ static int omap_l3_probe(struct platform_device *pdev)
 	return ret;
 }

+#ifdef	CONFIG_PM
+
+/**
+ * l3_resume_noirq() - resume function for l3_noc
+ * @dev:	pointer to l3_noc device structure
+ *
+ * We only have the resume handler only since we
+ * have already maintained the delta register
+ * configuration as part of configuring the system
+ */
+static int l3_resume_noirq(struct device *dev)
+{
+	struct omap_l3 *l3 = dev_get_drvdata(dev);
+	int i;
+	struct l3_flagmux_data *flag_mux;
+	void __iomem *base, *mask_regx = NULL;
+	u32 mask_val;
+
+	for (i = 0; i < l3->num_modules; i++) {
+		base = l3->l3_base[i];
+		flag_mux = l3->l3_flagmux[i];
+		if (!flag_mux->mask_app_bits && !flag_mux->mask_dbg_bits)
+			continue;
+
+		mask_regx = base + flag_mux->offset + L3_FLAGMUX_MASK0 +
+			   (L3_APPLICATION_ERROR << 3);
+		mask_val = readl_relaxed(mask_regx);
+		mask_val &= ~(flag_mux->mask_app_bits);
+
+		writel_relaxed(mask_val, mask_regx);
+		mask_regx = base + flag_mux->offset + L3_FLAGMUX_MASK0 +
+			   (L3_DEBUG_ERROR << 3);
+		mask_val = readl_relaxed(mask_regx);
+		mask_val &= ~(flag_mux->mask_dbg_bits);
+
+		writel_relaxed(mask_val, mask_regx);
+	}
+
+	/* Dummy read to force OCP barrier */
+	if (mask_regx)
+		(void)readl(mask_regx);
+
+	return 0;
+}
+
+static const struct dev_pm_ops l3_dev_pm_ops = {
+	.resume_noirq		= l3_resume_noirq,
+};
+
+#define L3_DEV_PM_OPS (&l3_dev_pm_ops)
+#else
+#define L3_DEV_PM_OPS NULL
+#endif
+
 static struct platform_driver omap_l3_driver = {
 	.probe		= omap_l3_probe,
 	.driver		= {
 		.name		= "omap_l3_noc",
 		.owner		= THIS_MODULE,
+		.pm		= L3_DEV_PM_OPS,
 		.of_match_table = of_match_ptr(l3_noc_match),
 	},
 };
--
2.1.4