intel_th: pti: Support Low Power Path output port type

The Low Power Path (LPP) output port type, looks mostly like PTI to
the software, with a few additional bits in the control register.

This extends the PTI driver to support LPP ports as well.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>

drivers/hwtracing/intel_th/pti.c

 /*
  * Intel(R) Trace Hub PTI output driver
  *
- * Copyright (C) 2014-2015 Intel Corporation.
+ * Copyright (C) 2014-2016 Intel Corporation.
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms and conditions of the GNU General Public License,
@@ -34,6 +34,8 @@ struct pti_device {
 	unsigned int		freeclk;
 	unsigned int		clkdiv;
 	unsigned int		patgen;
+	unsigned int		lpp_dest_mask;
+	unsigned int		lpp_dest;
 };
 
 /* map PTI widths to MODE settings of PTI_CTL register */
@@ -163,6 +165,7 @@ static int intel_th_pti_activate(struct intel_th_device *thdev)
 		ctl |= PTI_FCEN;
 	ctl |= pti->mode << __ffs(PTI_MODE);
 	ctl |= pti->clkdiv << __ffs(PTI_CLKDIV);
+	ctl |= pti->lpp_dest << __ffs(LPP_DEST);
 
 	iowrite32(ctl, pti->base + REG_PTI_CTL);
 
@@ -192,6 +195,15 @@ static void read_hw_config(struct pti_device *pti)
 		pti->mode = pti_width_mode(4);
 	if (!pti->clkdiv)
 		pti->clkdiv = 1;
+
+	if (pti->thdev->output.type == GTH_LPP) {
+		if (ctl & LPP_PTIPRESENT)
+			pti->lpp_dest_mask |= LPP_DEST_PTI;
+		if (ctl & LPP_BSSBPRESENT)
+			pti->lpp_dest_mask |= LPP_DEST_EXI;
+		if (ctl & LPP_DEST)
+			pti->lpp_dest = 1;
+	}
 }
 
 static int intel_th_pti_probe(struct intel_th_device *thdev)
@@ -239,10 +251,103 @@ static struct intel_th_driver intel_th_pti_driver = {
 	},
 };
 
-module_driver(intel_th_pti_driver,
-	      intel_th_driver_register,
-	      intel_th_driver_unregister);
+static const char * const lpp_dest_str[] = { "pti", "exi" };
+
+static ssize_t lpp_dest_show(struct device *dev, struct device_attribute *attr,
+			     char *buf)
+{
+	struct pti_device *pti = dev_get_drvdata(dev);
+	ssize_t ret = 0;
+	int i;
+
+	for (i = ARRAY_SIZE(lpp_dest_str) - 1; i >= 0; i--) {
+		const char *fmt = pti->lpp_dest == i ? "[%s] " : "%s ";
+
+		if (!(pti->lpp_dest_mask & BIT(i)))
+			continue;
+
+		ret += scnprintf(buf + ret, PAGE_SIZE - ret,
+				 fmt, lpp_dest_str[i]);
+	}
+
+	if (ret)
+		buf[ret - 1] = '\n';
+
+	return ret;
+}
+
+static ssize_t lpp_dest_store(struct device *dev, struct device_attribute *attr,
+			      const char *buf, size_t size)
+{
+	struct pti_device *pti = dev_get_drvdata(dev);
+	ssize_t ret = -EINVAL;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(lpp_dest_str); i++)
+		if (sysfs_streq(buf, lpp_dest_str[i]))
+			break;
+
+	if (i < ARRAY_SIZE(lpp_dest_str) && pti->lpp_dest_mask & BIT(i)) {
+		pti->lpp_dest = i;
+		ret = size;
+	}
+
+	return ret;
+}
+
+static DEVICE_ATTR_RW(lpp_dest);
+
+static struct attribute *lpp_output_attrs[] = {
+	&dev_attr_mode.attr,
+	&dev_attr_freerunning_clock.attr,
+	&dev_attr_clock_divider.attr,
+	&dev_attr_lpp_dest.attr,
+	NULL,
+};
+
+static struct attribute_group lpp_output_group = {
+	.attrs	= lpp_output_attrs,
+};
+
+static struct intel_th_driver intel_th_lpp_driver = {
+	.probe		= intel_th_pti_probe,
+	.remove		= intel_th_pti_remove,
+	.activate	= intel_th_pti_activate,
+	.deactivate	= intel_th_pti_deactivate,
+	.attr_group	= &lpp_output_group,
+	.driver	= {
+		.name	= "lpp",
+		.owner	= THIS_MODULE,
+	},
+};
+
+static int __init intel_th_pti_lpp_init(void)
+{
+	int err;
+
+	err = intel_th_driver_register(&intel_th_pti_driver);
+	if (err)
+		return err;
+
+	err = intel_th_driver_register(&intel_th_lpp_driver);
+	if (err) {
+		intel_th_driver_unregister(&intel_th_pti_driver);
+		return err;
+	}
+
+	return 0;
+}
+
+module_init(intel_th_pti_lpp_init);
+
+static void __exit intel_th_pti_lpp_exit(void)
+{
+	intel_th_driver_unregister(&intel_th_pti_driver);
+	intel_th_driver_unregister(&intel_th_lpp_driver);
+}
+
+module_exit(intel_th_pti_lpp_exit);
 
 MODULE_LICENSE("GPL v2");
-MODULE_DESCRIPTION("Intel(R) Trace Hub PTI output driver");
+MODULE_DESCRIPTION("Intel(R) Trace Hub PTI/LPP output driver");
 MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@linux.intel.com>");

drivers/hwtracing/intel_th/pti.h

@@ -23,7 +23,15 @@ enum {
 #define PTI_EN		BIT(0)
 #define PTI_FCEN	BIT(1)
 #define PTI_MODE	0xf0
+#define LPP_PTIPRESENT	BIT(8)
+#define LPP_BSSBPRESENT	BIT(9)
 #define PTI_CLKDIV	0x000f0000
 #define PTI_PATGENMODE	0x00f00000
+#define LPP_DEST	BIT(25)
+#define LPP_BSSBACT	BIT(30)
+#define LPP_LPPBUSY	BIT(31)
+
+#define LPP_DEST_PTI	BIT(0)
+#define LPP_DEST_EXI	BIT(1)
 
 #endif /* __INTEL_TH_STH_H__ */