linux-kernel - [PATCH v4 2/3] drivers: amba: Update component matching to use the CoreSight UCI values.

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Message-Id: <20190130234051.2294-3-mike.leach@linaro.org>
Date:   Wed, 30 Jan 2019 23:40:50 +0000
From:   Mike Leach <mike.leach@...aro.org>
To:     mike.leach@...aro.org, linux-arm-kernel@...ts.infradead.org,
        coresight@...ts.linaro.org, linux-kernel@...r.kernel.org
Cc:     linux@...linux.org.uk, saiprakash.ranjan@...eaurora.org,
        mathieu.poirier@...aro.org, suzuki.poulose@....com, arm@...nel.org
Subject: [PATCH v4 2/3] drivers: amba: Update component matching to use the CoreSight UCI values.

The patches provide an update of amba_device and matching code to handle
the additional registers required for the Class 0x9 (CoreSight) UCI.

The *data pointer in the amba_id is used by the driver to provide extended
ID register values for matching.

CoreSight components where PID/CID pair is currently sufficient for
unique identification need not provide this additional information.

Signed-off-by: Mike Leach <mike.leach@...aro.org>
---
 drivers/amba/bus.c       | 45 +++++++++++++++++++++++++++++++++-------
 include/linux/amba/bus.h |  6 ++++++
 2 files changed, 43 insertions(+), 8 deletions(-)

diff --git a/drivers/amba/bus.c b/drivers/amba/bus.c
index 41b706403ef7..b4dae624b9af 100644
--- a/drivers/amba/bus.c
+++ b/drivers/amba/bus.c
@@ -26,19 +26,36 @@
 
 #define to_amba_driver(d)	container_of(d, struct amba_driver, drv)
 
-static const struct amba_id *
-amba_lookup(const struct amba_id *table, struct amba_device *dev)
+/* called on periphid match and class 0x9 coresight device. */
+static int
+amba_cs_uci_id_match(const struct amba_id *table, struct amba_device *dev)
 {
 	int ret = 0;
+	struct amba_cs_uci_id *uci;
+
+	uci = table->data;
 
+	/* no table data or zero mask - return match on periphid */
+	if (!uci || (uci->devarch_mask == 0))
+		return 1;
+
+	/* test against read devtype and masked devarch value */
+	ret = (dev->uci.devtype == uci->devtype) &&
+		((dev->uci.devarch & uci->devarch_mask) == uci->devarch);
+	return ret;
+}
+
+static const struct amba_id *
+amba_lookup(const struct amba_id *table, struct amba_device *dev)
+{
 	while (table->mask) {
-		ret = (dev->periphid & table->mask) == table->id;
-		if (ret)
-			break;
+		if (((dev->periphid & table->mask) == table->id) &&
+			((dev->cid != CORESIGHT_CID) ||
+			 (amba_cs_uci_id_match(table, dev))))
+			return table;
 		table++;
 	}
-
-	return ret ? table : NULL;
+	return NULL;
 }
 
 static int amba_match(struct device *dev, struct device_driver *drv)
@@ -399,10 +416,22 @@ static int amba_device_try_add(struct amba_device *dev, struct resource *parent)
 			cid |= (readl(tmp + size - 0x10 + 4 * i) & 255) <<
 				(i * 8);
 
+		if (cid == CORESIGHT_CID) {
+			/* set the base to the start of the last 4k block */
+			void __iomem *csbase = tmp + size - 4096;
+
+			dev->uci.devarch =
+				readl(csbase + UCI_REG_DEVARCH_OFFSET);
+			dev->uci.devtype =
+				readl(csbase + UCI_REG_DEVTYPE_OFFSET) & 0xff;
+		}
+
 		amba_put_disable_pclk(dev);
 
-		if (cid == AMBA_CID || cid == CORESIGHT_CID)
+		if (cid == AMBA_CID || cid == CORESIGHT_CID) {
 			dev->periphid = pid;
+			dev->cid = cid;
+		}
 
 		if (!dev->periphid)
 			ret = -ENODEV;
diff --git a/include/linux/amba/bus.h b/include/linux/amba/bus.h
index e3c36223e40b..f99b74a6e4ca 100644
--- a/include/linux/amba/bus.h
+++ b/include/linux/amba/bus.h
@@ -58,6 +58,10 @@ struct amba_cs_uci_id {
 	void *data;
 };
 
+/* define offsets for registers used by UCI */
+#define UCI_REG_DEVTYPE_OFFSET	0xFCC
+#define UCI_REG_DEVARCH_OFFSET	0xFBC
+
 struct clk;
 
 struct amba_device {
@@ -65,6 +69,8 @@ struct amba_device {
 	struct resource		res;
 	struct clk		*pclk;
 	unsigned int		periphid;
+	unsigned int		cid;
+	struct amba_cs_uci_id	uci;
 	unsigned int		irq[AMBA_NR_IRQS];
 	char			*driver_override;
 };
-- 
2.19.1