[PATCH 0/4] n2rng: add support for m5/m7 rng register layout

[PATCH 0/4] n2rng: add support for m5/m7 rng register layout

[Shannon Nelson]

Commit c1e9b3b0eea1 ("hwrng: n2 - Attach on T5/M5, T7/M7 SPARC CPUs")
added config strings to enable the random number generator in the sparc
m5 and m7 platforms.  This worked fine for client LDoms, but not for the
primary LDom, or running on bare metal, because the actual rng hardware
layout changed and self-test would now fail, continually spewing error
messages on the console.

This patch series adds correct support for the new rng register layout,
and adds a limiter to the spewing of error messages.

Orabug: 25127795

Shannon Nelson (4):
  n2rng: limit error spewage when self-test fails
  n2rng: add device data descriptions
  n2rng: support new hardware register layout
  n2rng: update version info

 drivers/char/hw_random/n2-drv.c |  204 +++++++++++++++++++++++++++++----------
 drivers/char/hw_random/n2rng.h  |   51 ++++++++--
 2 files changed, 196 insertions(+), 59 deletions(-)

[PATCH 1/4] n2rng: limit error spewage when self-test fails

[Shannon Nelson]

If the self-test fails, it probably won't actually suddenly
start working.  Currently, this causes an endless spew of
error messages on the console and in the logs, so this patch
adds a limiter to the test.

Reported-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Signed-off-by: Shannon Nelson <shannon.nelson@oracle.com>
---
 drivers/char/hw_random/n2-drv.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/drivers/char/hw_random/n2-drv.c b/drivers/char/hw_random/n2-drv.c
index 3b06c1d..102560f 100644
--- a/drivers/char/hw_random/n2-drv.c
+++ b/drivers/char/hw_random/n2-drv.c
@@ -589,6 +589,7 @@ static void n2rng_work(struct work_struct *work)
 {
 	struct n2rng *np = container_of(work, struct n2rng, work.work);
 	int err = 0;
+	static int retries = 4;
 
 	if (!(np->flags & N2RNG_FLAG_CONTROL)) {
 		err = n2rng_guest_check(np);
@@ -606,7 +607,9 @@ static void n2rng_work(struct work_struct *work)
 		dev_info(&np->op->dev, "RNG ready\n");
 	}
 
-	if (err && !(np->flags & N2RNG_FLAG_SHUTDOWN))
+	if (--retries == 0)
+		dev_err(&np->op->dev, "Self-test retries failed, RNG not ready\n");
+	else if (err && !(np->flags & N2RNG_FLAG_SHUTDOWN))
 		schedule_delayed_work(&np->work, HZ * 2);
 }
 
-- 
1.7.1

[PATCH 2/4] n2rng: add device data descriptions

[Shannon Nelson]

Since we're going to need to keep track of more than just one
attribute of the hardware, we'll change the use of the data field
from the match struct from a single flag to a struct pointer.
This patch adds the struct template and initial descriptions.

Signed-off-by: Shannon Nelson <shannon.nelson@oracle.com>
---
 drivers/char/hw_random/n2-drv.c |   47 ++++++++++++++++++++++++++++++++------
 drivers/char/hw_random/n2rng.h  |   15 ++++++++++++
 2 files changed, 54 insertions(+), 8 deletions(-)

diff --git a/drivers/char/hw_random/n2-drv.c b/drivers/char/hw_random/n2-drv.c
index 102560f..74c26c7 100644
--- a/drivers/char/hw_random/n2-drv.c
+++ b/drivers/char/hw_random/n2-drv.c
@@ -625,24 +625,23 @@ static void n2rng_driver_version(void)
 static int n2rng_probe(struct platform_device *op)
 {
 	const struct of_device_id *match;
-	int multi_capable;
 	int err = -ENOMEM;
 	struct n2rng *np;
 
 	match = of_match_device(n2rng_match, &op->dev);
 	if (!match)
 		return -EINVAL;
-	multi_capable = (match->data != NULL);
 
 	n2rng_driver_version();
 	np = devm_kzalloc(&op->dev, sizeof(*np), GFP_KERNEL);
 	if (!np)
 		goto out;
 	np->op = op;
+	np->data = (struct n2rng_template *)match->data;
 
 	INIT_DELAYED_WORK(&np->work, n2rng_work);
 
-	if (multi_capable)
+	if (np->data->multi_capable)
 		np->flags |= N2RNG_FLAG_MULTI;
 
 	err = -ENODEV;
@@ -673,8 +672,9 @@ static int n2rng_probe(struct platform_device *op)
 			dev_err(&op->dev, "VF RNG lacks rng-#units property\n");
 			goto out_hvapi_unregister;
 		}
-	} else
+	} else {
 		np->num_units = 1;
+	}
 
 	dev_info(&op->dev, "Registered RNG HVAPI major %lu minor %lu\n",
 		 np->hvapi_major, np->hvapi_minor);
@@ -731,30 +731,61 @@ static int n2rng_remove(struct platform_device *op)
 	return 0;
 }
 
+static struct n2rng_template n2_template = {
+	.id = N2_n2_rng,
+	.multi_capable = 0,
+	.chip_version = 1,
+};
+
+static struct n2rng_template vf_template = {
+	.id = N2_vf_rng,
+	.multi_capable = 1,
+	.chip_version = 1,
+};
+
+static struct n2rng_template kt_template = {
+	.id = N2_kt_rng,
+	.multi_capable = 1,
+	.chip_version = 1,
+};
+
+static struct n2rng_template m4_template = {
+	.id = N2_m4_rng,
+	.multi_capable = 1,
+	.chip_version = 2,
+};
+
+static struct n2rng_template m7_template = {
+	.id = N2_m7_rng,
+	.multi_capable = 1,
+	.chip_version = 2,
+};
+
 static const struct of_device_id n2rng_match[] = {
 	{
 		.name		= "random-number-generator",
 		.compatible	= "SUNW,n2-rng",
+		.data		= &n2_template,
 	},
 	{
 		.name		= "random-number-generator",
 		.compatible	= "SUNW,vf-rng",
-		.data		= (void *) 1,
+		.data		= &vf_template,
 	},
 	{
 		.name		= "random-number-generator",
 		.compatible	= "SUNW,kt-rng",
-		.data		= (void *) 1,
+		.data		= &kt_template,
 	},
 	{
 		.name		= "random-number-generator",
 		.compatible	= "ORCL,m4-rng",
-		.data		= (void *) 1,
+		.data		= &m4_template,
 	},
 	{
 		.name		= "random-number-generator",
 		.compatible	= "ORCL,m7-rng",
-		.data		= (void *) 1,
+		.data		= &m7_template,
 	},
 	{},
 };
diff --git a/drivers/char/hw_random/n2rng.h b/drivers/char/hw_random/n2rng.h
index f244ac8..e41e55a 100644
--- a/drivers/char/hw_random/n2rng.h
+++ b/drivers/char/hw_random/n2rng.h
@@ -60,6 +60,20 @@ extern unsigned long sun4v_rng_data_read_diag_v2(unsigned long data_ra,
 extern unsigned long sun4v_rng_data_read(unsigned long data_ra,
 					 unsigned long *tick_delta);
 
+enum n2rng_compat_id {
+	N2_n2_rng,
+	N2_vf_rng,
+	N2_kt_rng,
+	N2_m4_rng,
+	N2_m7_rng,
+};
+
+struct n2rng_template {
+	enum n2rng_compat_id id;
+	int multi_capable;
+	int chip_version;
+};
+
 struct n2rng_unit {
 	u64			control[HV_RNG_NUM_CONTROL];
 };
@@ -74,6 +88,7 @@ struct n2rng {
 #define N2RNG_FLAG_SHUTDOWN	0x00000010 /* Driver unregistering        */
 #define N2RNG_FLAG_BUFFER_VALID	0x00000020 /* u32 buffer holds valid data */
 
+	struct n2rng_template	*data;
 	int			num_units;
 	struct n2rng_unit	*units;
 
-- 
1.7.1

[PATCH 3/4] n2rng: support new hardware register layout

[Shannon Nelson]

Add the new register layout constants and the requisite logic
for using them.

Signed-off-by: Shannon Nelson <shannon.nelson@oracle.com>
---
 drivers/char/hw_random/n2-drv.c |  144 +++++++++++++++++++++++++++++----------
 drivers/char/hw_random/n2rng.h  |   36 +++++++---
 2 files changed, 134 insertions(+), 46 deletions(-)

diff --git a/drivers/char/hw_random/n2-drv.c b/drivers/char/hw_random/n2-drv.c
index 74c26c7..f0bd5ee 100644
--- a/drivers/char/hw_random/n2-drv.c
+++ b/drivers/char/hw_random/n2-drv.c
@@ -302,26 +302,57 @@ static int n2rng_try_read_ctl(struct n2rng *np)
 	return n2rng_hv_err_trans(hv_err);
 }
 
-#define CONTROL_DEFAULT_BASE		\
-	((2 << RNG_CTL_ASEL_SHIFT) |	\
-	 (N2RNG_ACCUM_CYCLES_DEFAULT << RNG_CTL_WAIT_SHIFT) |	\
-	 RNG_CTL_LFSR)
-
-#define CONTROL_DEFAULT_0		\
-	(CONTROL_DEFAULT_BASE |		\
-	 (1 << RNG_CTL_VCO_SHIFT) |	\
-	 RNG_CTL_ES1)
-#define CONTROL_DEFAULT_1		\
-	(CONTROL_DEFAULT_BASE |		\
-	 (2 << RNG_CTL_VCO_SHIFT) |	\
-	 RNG_CTL_ES2)
-#define CONTROL_DEFAULT_2		\
-	(CONTROL_DEFAULT_BASE |		\
-	 (3 << RNG_CTL_VCO_SHIFT) |	\
-	 RNG_CTL_ES3)
-#define CONTROL_DEFAULT_3		\
-	(CONTROL_DEFAULT_BASE |		\
-	 RNG_CTL_ES1 | RNG_CTL_ES2 | RNG_CTL_ES3)
+static u64 n2rng_control_default(struct n2rng *np, int ctl)
+{
+	u64 val = 0;
+
+	if (np->data->chip_version == 1) {
+		val = ((2 << RNG_v1_CTL_ASEL_SHIFT) |
+			(N2RNG_ACCUM_CYCLES_DEFAULT << RNG_v1_CTL_WAIT_SHIFT) |
+			 RNG_CTL_LFSR);
+
+		switch (ctl) {
+		case 0:
+			val |= (1 << RNG_v1_CTL_VCO_SHIFT) | RNG_CTL_ES1;
+			break;
+		case 1:
+			val |= (2 << RNG_v1_CTL_VCO_SHIFT) | RNG_CTL_ES2;
+			break;
+		case 2:
+			val |= (3 << RNG_v1_CTL_VCO_SHIFT) | RNG_CTL_ES3;
+			break;
+		case 3:
+			val |= RNG_CTL_ES1 | RNG_CTL_ES2 | RNG_CTL_ES3;
+			break;
+		default:
+			break;
+		}
+
+	} else {
+		val = ((2 << RNG_v2_CTL_ASEL_SHIFT) |
+			(N2RNG_ACCUM_CYCLES_DEFAULT << RNG_v2_CTL_WAIT_SHIFT) |
+			 RNG_CTL_LFSR);
+
+		switch (ctl) {
+		case 0:
+			val |= (1 << RNG_v2_CTL_VCO_SHIFT) | RNG_CTL_ES1;
+			break;
+		case 1:
+			val |= (2 << RNG_v2_CTL_VCO_SHIFT) | RNG_CTL_ES2;
+			break;
+		case 2:
+			val |= (3 << RNG_v2_CTL_VCO_SHIFT) | RNG_CTL_ES3;
+			break;
+		case 3:
+			val |= RNG_CTL_ES1 | RNG_CTL_ES2 | RNG_CTL_ES3;
+			break;
+		default:
+			break;
+		}
+	}
+
+	return val;
+}
 
 static void n2rng_control_swstate_init(struct n2rng *np)
 {
@@ -336,10 +367,10 @@ static void n2rng_control_swstate_init(struct n2rng *np)
 	for (i = 0; i < np->num_units; i++) {
 		struct n2rng_unit *up = &np->units[i];
 
-		up->control[0] = CONTROL_DEFAULT_0;
-		up->control[1] = CONTROL_DEFAULT_1;
-		up->control[2] = CONTROL_DEFAULT_2;
-		up->control[3] = CONTROL_DEFAULT_3;
+		up->control[0] = n2rng_control_default(np, 0);
+		up->control[1] = n2rng_control_default(np, 1);
+		up->control[2] = n2rng_control_default(np, 2);
+		up->control[3] = n2rng_control_default(np, 3);
 	}
 
 	np->hv_state = HV_RNG_STATE_UNCONFIGURED;
@@ -399,6 +430,7 @@ static int n2rng_data_read(struct hwrng *rng, u32 *data)
 	} else {
 		int err = n2rng_generic_read_data(ra);
 		if (!err) {
+			np->flags |= N2RNG_FLAG_BUFFER_VALID;
 			np->buffer = np->test_data >> 32;
 			*data = np->test_data & 0xffffffff;
 			len = 4;
@@ -487,9 +519,21 @@ static void n2rng_dump_test_buffer(struct n2rng *np)
 
 static int n2rng_check_selftest_buffer(struct n2rng *np, unsigned long unit)
 {
-	u64 val = SELFTEST_VAL;
+	u64 val;
 	int err, matches, limit;
 
+	switch (np->data->id) {
+	case N2_n2_rng:
+	case N2_vf_rng:
+	case N2_kt_rng:
+	case N2_m4_rng:  /* yes, m4 uses the old value */
+		val = RNG_v1_SELFTEST_VAL;
+		break;
+	default:
+		val = RNG_v2_SELFTEST_VAL;
+		break;
+	}
+
 	matches = 0;
 	for (limit = 0; limit < SELFTEST_LOOPS_MAX; limit++) {
 		matches += n2rng_test_buffer_find(np, val);
@@ -512,14 +556,32 @@ static int n2rng_check_selftest_buffer(struct n2rng *np, unsigned long unit)
 static int n2rng_control_selftest(struct n2rng *np, unsigned long unit)
 {
 	int err;
+	u64 base, base3;
+
+	switch (np->data->id) {
+	case N2_n2_rng:
+	case N2_vf_rng:
+	case N2_kt_rng:
+		base = RNG_v1_CTL_ASEL_NOOUT << RNG_v1_CTL_ASEL_SHIFT;
+		base3 = base | RNG_CTL_LFSR |
+			((RNG_v1_SELFTEST_TICKS - 2) << RNG_v1_CTL_WAIT_SHIFT);
+		break;
+	case N2_m4_rng:
+		base = RNG_v2_CTL_ASEL_NOOUT << RNG_v2_CTL_ASEL_SHIFT;
+		base3 = base | RNG_CTL_LFSR |
+			((RNG_v1_SELFTEST_TICKS - 2) << RNG_v2_CTL_WAIT_SHIFT);
+		break;
+	default:
+		base = RNG_v2_CTL_ASEL_NOOUT << RNG_v2_CTL_ASEL_SHIFT;
+		base3 = base | RNG_CTL_LFSR |
+			(RNG_v2_SELFTEST_TICKS << RNG_v2_CTL_WAIT_SHIFT);
+		break;
+	}
 
-	np->test_control[0] = (0x2 << RNG_CTL_ASEL_SHIFT);
-	np->test_control[1] = (0x2 << RNG_CTL_ASEL_SHIFT);
-	np->test_control[2] = (0x2 << RNG_CTL_ASEL_SHIFT);
-	np->test_control[3] = ((0x2 << RNG_CTL_ASEL_SHIFT) |
-			       RNG_CTL_LFSR |
-			       ((SELFTEST_TICKS - 2) << RNG_CTL_WAIT_SHIFT));
-
+	np->test_control[0] = base;
+	np->test_control[1] = base;
+	np->test_control[2] = base;
+	np->test_control[3] = base3;
 
 	err = n2rng_entropy_diag_read(np, unit, np->test_control,
 				      HV_RNG_STATE_HEALTHCHECK,
@@ -557,11 +619,19 @@ static int n2rng_control_configure_units(struct n2rng *np)
 		struct n2rng_unit *up = &np->units[unit];
 		unsigned long ctl_ra = __pa(&up->control[0]);
 		int esrc;
-		u64 base;
+		u64 base, shift;
 
-		base = ((np->accum_cycles << RNG_CTL_WAIT_SHIFT) |
-			(2 << RNG_CTL_ASEL_SHIFT) |
-			RNG_CTL_LFSR);
+		if (np->data->chip_version == 1) {
+			base = ((np->accum_cycles << RNG_v1_CTL_WAIT_SHIFT) |
+			      (RNG_v1_CTL_ASEL_NOOUT << RNG_v1_CTL_ASEL_SHIFT) |
+			      RNG_CTL_LFSR);
+			shift = RNG_v1_CTL_VCO_SHIFT;
+		} else {
+			base = ((np->accum_cycles << RNG_v2_CTL_WAIT_SHIFT) |
+			      (RNG_v2_CTL_ASEL_NOOUT << RNG_v2_CTL_ASEL_SHIFT) |
+			      RNG_CTL_LFSR);
+			shift = RNG_v2_CTL_VCO_SHIFT;
+		}
 
 		/* XXX This isn't the best.  We should fetch a bunch
 		 * XXX of words using each entropy source combined XXX
@@ -570,7 +640,7 @@ static int n2rng_control_configure_units(struct n2rng *np)
 		 */
 		for (esrc = 0; esrc < 3; esrc++)
 			up->control[esrc] = base |
-				(esrc << RNG_CTL_VCO_SHIFT) |
+				(esrc << shift) |
 				(RNG_CTL_ES1 << esrc);
 
 		up->control[3] = base |
diff --git a/drivers/char/hw_random/n2rng.h b/drivers/char/hw_random/n2rng.h
index e41e55a..6bad6cc 100644
--- a/drivers/char/hw_random/n2rng.h
+++ b/drivers/char/hw_random/n2rng.h
@@ -6,18 +6,34 @@
 #ifndef _N2RNG_H
 #define _N2RNG_H
 
-#define RNG_CTL_WAIT       0x0000000001fffe00ULL /* Minimum wait time       */
-#define RNG_CTL_WAIT_SHIFT 9
-#define RNG_CTL_BYPASS     0x0000000000000100ULL /* VCO voltage source      */
-#define RNG_CTL_VCO        0x00000000000000c0ULL /* VCO rate control        */
-#define RNG_CTL_VCO_SHIFT  6
-#define RNG_CTL_ASEL       0x0000000000000030ULL /* Analog MUX select       */
-#define RNG_CTL_ASEL_SHIFT 4
+/* ver1 devices - n2-rng, vf-rng, kt-rng */
+#define RNG_v1_CTL_WAIT       0x0000000001fffe00ULL /* Minimum wait time    */
+#define RNG_v1_CTL_WAIT_SHIFT 9
+#define RNG_v1_CTL_BYPASS     0x0000000000000100ULL /* VCO voltage source   */
+#define RNG_v1_CTL_VCO        0x00000000000000c0ULL /* VCO rate control     */
+#define RNG_v1_CTL_VCO_SHIFT  6
+#define RNG_v1_CTL_ASEL       0x0000000000000030ULL /* Analog MUX select    */
+#define RNG_v1_CTL_ASEL_SHIFT 4
+#define RNG_v1_CTL_ASEL_NOOUT 2
+
+/* these are the same in v2 as in v1 */
 #define RNG_CTL_LFSR       0x0000000000000008ULL /* Use LFSR or plain shift */
 #define RNG_CTL_ES3        0x0000000000000004ULL /* Enable entropy source 3 */
 #define RNG_CTL_ES2        0x0000000000000002ULL /* Enable entropy source 2 */
 #define RNG_CTL_ES1        0x0000000000000001ULL /* Enable entropy source 1 */
 
+/* ver2 devices - m4-rng, m7-rng */
+#define RNG_v2_CTL_WAIT       0x0000000007fff800ULL /* Minimum wait time    */
+#define RNG_v2_CTL_WAIT_SHIFT 12
+#define RNG_v2_CTL_BYPASS     0x0000000000000400ULL /* VCO voltage source   */
+#define RNG_v2_CTL_VCO        0x0000000000000300ULL /* VCO rate control     */
+#define RNG_v2_CTL_VCO_SHIFT  9
+#define RNG_v2_CTL_PERF       0x0000000000000180ULL /* Perf */
+#define RNG_v2_CTL_ASEL       0x0000000000000070ULL /* Analog MUX select    */
+#define RNG_v2_CTL_ASEL_SHIFT 4
+#define RNG_v2_CTL_ASEL_NOOUT 7
+
+
 #define HV_FAST_RNG_GET_DIAG_CTL	0x130
 #define HV_FAST_RNG_CTL_READ		0x131
 #define HV_FAST_RNG_CTL_WRITE		0x132
@@ -112,8 +128,10 @@ struct n2rng {
 
 	u64			scratch_control[HV_RNG_NUM_CONTROL];
 
-#define SELFTEST_TICKS		38859
-#define SELFTEST_VAL		((u64)0xB8820C7BD387E32C)
+#define RNG_v1_SELFTEST_TICKS	38859
+#define RNG_v1_SELFTEST_VAL	((u64)0xB8820C7BD387E32C)
+#define RNG_v2_SELFTEST_TICKS	64
+#define RNG_v2_SELFTEST_VAL	((u64)0xffffffffffffffff)
 #define SELFTEST_POLY		((u64)0x231DCEE91262B8A3)
 #define SELFTEST_MATCH_GOAL	6
 #define SELFTEST_LOOPS_MAX	40000
-- 
1.7.1

[PATCH 4/4] n2rng: update version info

[Shannon Nelson]

Signed-off-by: Shannon Nelson <shannon.nelson@oracle.com>
---
 drivers/char/hw_random/n2-drv.c |    8 ++++----
 1 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/char/hw_random/n2-drv.c b/drivers/char/hw_random/n2-drv.c
index f0bd5ee..31cbdbb 100644
--- a/drivers/char/hw_random/n2-drv.c
+++ b/drivers/char/hw_random/n2-drv.c
@@ -21,11 +21,11 @@
 
 #define DRV_MODULE_NAME		"n2rng"
 #define PFX DRV_MODULE_NAME	": "
-#define DRV_MODULE_VERSION	"0.2"
-#define DRV_MODULE_RELDATE	"July 27, 2011"
+#define DRV_MODULE_VERSION	"0.3"
+#define DRV_MODULE_RELDATE	"Jan 7, 2017"
 
 static char version[] =
-	DRV_MODULE_NAME ".c:v" DRV_MODULE_VERSION " (" DRV_MODULE_RELDATE ")\n";
+	DRV_MODULE_NAME " v" DRV_MODULE_VERSION " (" DRV_MODULE_RELDATE ")\n";
 
 MODULE_AUTHOR("David S. Miller (davem@davemloft.net)");
 MODULE_DESCRIPTION("Niagara2 RNG driver");
@@ -765,7 +765,7 @@ static int n2rng_probe(struct platform_device *op)
 		  "multi-unit-capable" : "single-unit"),
 		 np->num_units);
 
-	np->hwrng.name = "n2rng";
+	np->hwrng.name = DRV_MODULE_NAME;
 	np->hwrng.data_read = n2rng_data_read;
 	np->hwrng.priv = (unsigned long) np;
 
-- 
1.7.1

Re: [PATCH 0/4] n2rng: add support for m5/m7 rng register layout

[Herbert Xu]

On Thu, Jan 12, 2017 at 10:52:45AM -0800, Shannon Nelson wrote:
> Commit c1e9b3b0eea1 ("hwrng: n2 - Attach on T5/M5, T7/M7 SPARC CPUs")
> added config strings to enable the random number generator in the sparc
> m5 and m7 platforms.  This worked fine for client LDoms, but not for the
> primary LDom, or running on bare metal, because the actual rng hardware
> layout changed and self-test would now fail, continually spewing error
> messages on the console.
> 
> This patch series adds correct support for the new rng register layout,
> and adds a limiter to the spewing of error messages.

All applied.  Thanks.
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt