[PATCH 2/2] bus: brcmstb_gisb: Add support for breakpoint interrupts

[Florian Fainelli <f.fainelli@gmail.com>]

GISB breakpoint interrupts can be raised when a breakpoint has been
enabled to match a specific master and/or GISB register address. Being
able to print a message, similar to those done during target abort or
timeout greatly helps debug systems.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
---
 drivers/bus/brcmstb_gisb.c | 96 +++++++++++++++++++++++++++++++++++++-
 1 file changed, 95 insertions(+), 1 deletion(-)

diff --git a/drivers/bus/brcmstb_gisb.c b/drivers/bus/brcmstb_gisb.c
index 7579439971e3..7355fa2cb439 100644
--- a/drivers/bus/brcmstb_gisb.c
+++ b/drivers/bus/brcmstb_gisb.c
@@ -30,8 +30,22 @@
 #define  ARB_ERR_CAP_STATUS_WRITE	(1 << 1)
 #define  ARB_ERR_CAP_STATUS_VALID	(1 << 0)
 
+#define  ARB_BP_CAP_CLEAR		(1 << 0)
+#define  ARB_BP_CAP_STATUS_PROT_SHIFT	14
+#define  ARB_BP_CAP_STATUS_TYPE		(1 << 13)
+#define  ARB_BP_CAP_STATUS_RSP_SHIFT	10
+#define  ARB_BP_CAP_STATUS_MASK		GENMASK(1, 0)
+#define  ARB_BP_CAP_STATUS_BS_SHIFT	2
+#define  ARB_BP_CAP_STATUS_WRITE	(1 << 1)
+#define  ARB_BP_CAP_STATUS_VALID	(1 << 0)
+
 enum {
 	ARB_TIMER,
+	ARB_BP_CAP_CLR,
+	ARB_BP_CAP_HI_ADDR,
+	ARB_BP_CAP_ADDR,
+	ARB_BP_CAP_STATUS,
+	ARB_BP_CAP_MASTER,
 	ARB_ERR_CAP_CLR,
 	ARB_ERR_CAP_HI_ADDR,
 	ARB_ERR_CAP_ADDR,
@@ -41,6 +55,11 @@ enum {
 
 static const int gisb_offsets_bcm7038[] = {
 	[ARB_TIMER]		= 0x00c,
+	[ARB_BP_CAP_CLR]	= 0x014,
+	[ARB_BP_CAP_HI_ADDR]	= -1,
+	[ARB_BP_CAP_ADDR]	= 0x0b8,
+	[ARB_BP_CAP_STATUS]	= 0x0c0,
+	[ARB_BP_CAP_MASTER]	= -1,
 	[ARB_ERR_CAP_CLR]	= 0x0c4,
 	[ARB_ERR_CAP_HI_ADDR]	= -1,
 	[ARB_ERR_CAP_ADDR]	= 0x0c8,
@@ -50,6 +69,11 @@ static const int gisb_offsets_bcm7038[] = {
 
 static const int gisb_offsets_bcm7278[] = {
 	[ARB_TIMER]		= 0x008,
+	[ARB_BP_CAP_CLR]	= 0x01c,
+	[ARB_BP_CAP_HI_ADDR]	= -1,
+	[ARB_BP_CAP_ADDR]	= 0x220,
+	[ARB_BP_CAP_STATUS]	= 0x230,
+	[ARB_BP_CAP_MASTER]	= 0x234,
 	[ARB_ERR_CAP_CLR]	= 0x7f8,
 	[ARB_ERR_CAP_HI_ADDR]	= -1,
 	[ARB_ERR_CAP_ADDR]	= 0x7e0,
@@ -59,6 +83,11 @@ static const int gisb_offsets_bcm7278[] = {
 
 static const int gisb_offsets_bcm7400[] = {
 	[ARB_TIMER]		= 0x00c,
+	[ARB_BP_CAP_CLR]	= 0x014,
+	[ARB_BP_CAP_HI_ADDR]	= -1,
+	[ARB_BP_CAP_ADDR]	= 0x0b8,
+	[ARB_BP_CAP_STATUS]	= 0x0c0,
+	[ARB_BP_CAP_MASTER]	= 0x0c4,
 	[ARB_ERR_CAP_CLR]	= 0x0c8,
 	[ARB_ERR_CAP_HI_ADDR]	= -1,
 	[ARB_ERR_CAP_ADDR]	= 0x0cc,
@@ -68,6 +97,11 @@ static const int gisb_offsets_bcm7400[] = {
 
 static const int gisb_offsets_bcm7435[] = {
 	[ARB_TIMER]		= 0x00c,
+	[ARB_BP_CAP_CLR]	= 0x014,
+	[ARB_BP_CAP_HI_ADDR]	= -1,
+	[ARB_BP_CAP_ADDR]	= 0x158,
+	[ARB_BP_CAP_STATUS]	= 0x160,
+	[ARB_BP_CAP_MASTER]	= 0x164,
 	[ARB_ERR_CAP_CLR]	= 0x168,
 	[ARB_ERR_CAP_HI_ADDR]	= -1,
 	[ARB_ERR_CAP_ADDR]	= 0x16c,
@@ -77,6 +111,11 @@ static const int gisb_offsets_bcm7435[] = {
 
 static const int gisb_offsets_bcm7445[] = {
 	[ARB_TIMER]		= 0x008,
+	[ARB_BP_CAP_CLR]	= 0x010,
+	[ARB_BP_CAP_HI_ADDR]	= -1,
+	[ARB_BP_CAP_ADDR]	= 0x1d8,
+	[ARB_BP_CAP_STATUS]	= 0x1e0,
+	[ARB_BP_CAP_MASTER]	= 0x1e4,
 	[ARB_ERR_CAP_CLR]	= 0x7e4,
 	[ARB_ERR_CAP_HI_ADDR]	= 0x7e8,
 	[ARB_ERR_CAP_ADDR]	= 0x7ec,
@@ -125,6 +164,16 @@ static u64 gisb_read_address(struct brcmstb_gisb_arb_device *gdev)
 	return value;
 }
 
+static u64 gisb_read_bp_address(struct brcmstb_gisb_arb_device *gdev)
+{
+	u64 value;
+
+	value = gisb_read(gdev, ARB_BP_CAP_ADDR);
+	value |= (u64)gisb_read(gdev, ARB_BP_CAP_HI_ADDR) << 32;
+
+	return value;
+}
+
 static void gisb_write(struct brcmstb_gisb_arb_device *gdev, u32 val, int reg)
 {
 	int offset = gdev->gisb_offsets[reg];
@@ -259,6 +308,41 @@ static irqreturn_t brcmstb_gisb_tea_handler(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
+static irqreturn_t brcmstb_gisb_bp_handler(int irq, void *dev_id)
+{
+	struct brcmstb_gisb_arb_device *gdev = dev_id;
+	const char *m_name;
+	u32 bp_status;
+	u64 arb_addr;
+	u32 master;
+	char m_fmt[11];
+
+	bp_status = gisb_read(gdev, ARB_BP_CAP_STATUS);
+
+	/* Invalid captured address, bail out */
+	if (!(bp_status & ARB_BP_CAP_STATUS_VALID))
+		return IRQ_HANDLED;
+
+	/* Read the address and master */
+	arb_addr = gisb_read_bp_address(gdev);
+	master = gisb_read(gdev, ARB_BP_CAP_MASTER);
+
+	m_name = brcmstb_gisb_master_to_str(gdev, master);
+	if (!m_name) {
+		snprintf(m_fmt, sizeof(m_fmt), "0x%08x", master);
+		m_name = m_fmt;
+	}
+
+	pr_crit("GISB: breakpoint at 0x%llx [%c], core: %s\n",
+		arb_addr, bp_status & ARB_BP_CAP_STATUS_WRITE ? 'W' : 'R',
+		m_name);
+
+	/* clear the GISB error */
+	gisb_write(gdev, ARB_ERR_CAP_CLEAR, ARB_ERR_CAP_CLR);
+
+	return IRQ_HANDLED;
+}
+
 /*
  * Dump out gisb errors on die or panic.
  */
@@ -317,13 +401,14 @@ static int __init brcmstb_gisb_arb_probe(struct platform_device *pdev)
 	struct brcmstb_gisb_arb_device *gdev;
 	const struct of_device_id *of_id;
 	struct resource *r;
-	int err, timeout_irq, tea_irq;
+	int err, timeout_irq, tea_irq, bp_irq;
 	unsigned int num_masters, j = 0;
 	int i, first, last;
 
 	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	timeout_irq = platform_get_irq(pdev, 0);
 	tea_irq = platform_get_irq(pdev, 1);
+	bp_irq = platform_get_irq(pdev, 2);
 
 	gdev = devm_kzalloc(&pdev->dev, sizeof(*gdev), GFP_KERNEL);
 	if (!gdev)
@@ -356,6 +441,15 @@ static int __init brcmstb_gisb_arb_probe(struct platform_device *pdev)
 	if (err < 0)
 		return err;
 
+	/* Interrupt is optional */
+	if (bp_irq > 0) {
+		err = devm_request_irq(&pdev->dev, bp_irq,
+				       brcmstb_gisb_bp_handler, 0, pdev->name,
+				       gdev);
+		if (err < 0)
+			return err;
+	}
+
 	/* If we do not have a valid mask, assume all masters are enabled */
 	if (of_property_read_u32(dn, "brcm,gisb-arb-master-mask",
 				&gdev->valid_mask))
-- 
2.25.1