[net,v5,1/2] ptp: ocp: adjust sysfs entries to expose tty information

Commit Message

Vadim Fedorenko Aug. 22, 2024, 3:44 p.m. UTC

Starting v6.8 the serial port subsystem changed the hierarchy of devices
and symlinks are not working anymore. Previous discussion made it clear
that the idea of symlinks for tty devices was wrong by design [1].
Implement additional attributes to expose the information. Fixes tag
points to the commit which introduced the change.

[1] https://lore.kernel.org/netdev/2024060503-subsonic-pupil-bbee@gregkh/

Fixes: b286f4e87e32 ("serial: core: Move tty and serdev to be children of serial core port device")
Signed-off-by: Vadim Fedorenko <[e-mail]>
---
 drivers/ptp/ptp_ocp.c | 168 +++++++++++++++++++++++++-----------------
 1 file changed, 101 insertions(+), 67 deletions(-)

Comments

Jiri Slaby Aug. 23, 2024, 6:10 a.m. UTC | #1

On 22. 08. 24, 17:44, Vadim Fedorenko wrote:
> Starting v6.8 the serial port subsystem changed the hierarchy of devices
> and symlinks are not working anymore. Previous discussion made it clear
> that the idea of symlinks for tty devices was wrong by design [1].
> Implement additional attributes to expose the information. Fixes tag
> points to the commit which introduced the change.
> 
> [1] https://lore.kernel.org/netdev/2024060503-subsonic-pupil-bbee@gregkh/
> 
> Fixes: b286f4e87e32 ("serial: core: Move tty and serdev to be children of serial core port device")
> Signed-off-by: Vadim Fedorenko <[e-mail]>

Looks good to me. Except I still think it should be 2 patches:

>> The conversion to the array needs to go to a separate patch, apparently.
> 
> I'm not sure here. I'm trying to fix the regression introduced back in
> 6.8. The conversion to the array itself doesn't solve the issue, it's
> pure net-next material.

It doesn't matter...

> But the simple fix was NACKed previously, that's
> why I had to introduce such a big change. I would like to keep these
> changes all together in one patch. 

No problem, if you plan on stable to pick this up, mark them both for Cc 
stable.

It's much easier to process in brain and review smaller changes, than a 
large single patch. And especially: it is less error-prone.

thanks,

Patch

diff --git a/drivers/ptp/ptp_ocp.c b/drivers/ptp/ptp_ocp.c
index ee2ced88ab34..e7479b9b90cb 100644
--- a/drivers/ptp/ptp_ocp.c
+++ b/drivers/ptp/ptp_ocp.c
@@ -316,6 +316,15 @@  struct ptp_ocp_serial_port {
 #define OCP_SERIAL_LEN			6
 #define OCP_SMA_NUM			4
 
+enum {
+	PORT_GNSS,
+	PORT_GNSS2,
+	PORT_MAC, /* miniature atomic clock */
+	PORT_NMEA,
+
+	__PORT_COUNT,
+};
+
 struct ptp_ocp {
 	struct pci_dev		*pdev;
 	struct device		dev;
@@ -357,10 +366,7 @@  struct ptp_ocp {
 	struct delayed_work	sync_work;
 	int			id;
 	int			n_irqs;
-	struct ptp_ocp_serial_port	gnss_port;
-	struct ptp_ocp_serial_port	gnss2_port;
-	struct ptp_ocp_serial_port	mac_port;   /* miniature atomic clock */
-	struct ptp_ocp_serial_port	nmea_port;
+	struct ptp_ocp_serial_port	port[__PORT_COUNT];
 	bool			fw_loader;
 	u8			fw_tag;
 	u16			fw_version;
@@ -655,28 +661,28 @@  static struct ocp_resource ocp_fb_resource[] = {
 		},
 	},
 	{
-		OCP_SERIAL_RESOURCE(gnss_port),
+		OCP_SERIAL_RESOURCE(port[PORT_GNSS]),
 		.offset = 0x00160000 + 0x1000, .irq_vec = 3,
 		.extra = &(struct ptp_ocp_serial_port) {
 			.baud = 115200,
 		},
 	},
 	{
-		OCP_SERIAL_RESOURCE(gnss2_port),
+		OCP_SERIAL_RESOURCE(port[PORT_GNSS2]),
 		.offset = 0x00170000 + 0x1000, .irq_vec = 4,
 		.extra = &(struct ptp_ocp_serial_port) {
 			.baud = 115200,
 		},
 	},
 	{
-		OCP_SERIAL_RESOURCE(mac_port),
+		OCP_SERIAL_RESOURCE(port[PORT_MAC]),
 		.offset = 0x00180000 + 0x1000, .irq_vec = 5,
 		.extra = &(struct ptp_ocp_serial_port) {
 			.baud = 57600,
 		},
 	},
 	{
-		OCP_SERIAL_RESOURCE(nmea_port),
+		OCP_SERIAL_RESOURCE(port[PORT_NMEA]),
 		.offset = 0x00190000 + 0x1000, .irq_vec = 10,
 	},
 	{
@@ -740,7 +746,7 @@  static struct ocp_resource ocp_art_resource[] = {
 		.offset = 0x01000000, .size = 0x10000,
 	},
 	{
-		OCP_SERIAL_RESOURCE(gnss_port),
+		OCP_SERIAL_RESOURCE(port[PORT_GNSS]),
 		.offset = 0x00160000 + 0x1000, .irq_vec = 3,
 		.extra = &(struct ptp_ocp_serial_port) {
 			.baud = 115200,
@@ -839,7 +845,7 @@  static struct ocp_resource ocp_art_resource[] = {
 		},
 	},
 	{
-		OCP_SERIAL_RESOURCE(mac_port),
+		OCP_SERIAL_RESOURCE(port[PORT_MAC]),
 		.offset = 0x00190000, .irq_vec = 7,
 		.extra = &(struct ptp_ocp_serial_port) {
 			.baud = 9600,
@@ -950,14 +956,14 @@  static struct ocp_resource ocp_adva_resource[] = {
 		.offset = 0x00220000, .size = 0x1000,
 	},
 	{
-		OCP_SERIAL_RESOURCE(gnss_port),
+		OCP_SERIAL_RESOURCE(port[PORT_GNSS]),
 		.offset = 0x00160000 + 0x1000, .irq_vec = 3,
 		.extra = &(struct ptp_ocp_serial_port) {
 			.baud = 9600,
 		},
 	},
 	{
-		OCP_SERIAL_RESOURCE(mac_port),
+		OCP_SERIAL_RESOURCE(port[PORT_MAC]),
 		.offset = 0x00180000 + 0x1000, .irq_vec = 5,
 		.extra = &(struct ptp_ocp_serial_port) {
 			.baud = 115200,
@@ -1649,6 +1655,15 @@  ptp_ocp_tod_gnss_name(int idx)
 	return gnss_name[idx];
 }
 
+static const char *
+ptp_ocp_tty_port_name(int idx)
+{
+	static const char * const tty_name[] = {
+		"GNSS", "GNSS2", "MAC", "NMEA"
+	};
+	return tty_name[idx];
+}
+
 struct ptp_ocp_nvmem_match_info {
 	struct ptp_ocp *bp;
 	const void * const tag;
@@ -3346,6 +3361,54 @@  static EXT_ATTR_RO(freq, frequency, 1);
 static EXT_ATTR_RO(freq, frequency, 2);
 static EXT_ATTR_RO(freq, frequency, 3);
 
+static ssize_t
+ptp_ocp_tty_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct dev_ext_attribute *ea = to_ext_attr(attr);
+	struct ptp_ocp *bp = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "ttyS%d", bp->port[(uintptr_t)ea->var].line);
+}
+
+static umode_t
+ptp_ocp_timecard_tty_is_visible(struct kobject *kobj, struct attribute *attr, int n)
+{
+	struct ptp_ocp *bp = dev_get_drvdata(kobj_to_dev(kobj));
+	struct ptp_ocp_serial_port *port;
+	struct device_attribute *dattr;
+	struct dev_ext_attribute *ea;
+
+	if (strncmp(attr->name, "tty", 3))
+		return attr->mode;
+
+	dattr = container_of(attr, struct device_attribute, attr);
+	ea = container_of(dattr, struct dev_ext_attribute, attr);
+	port = &bp->port[(uintptr_t)ea->var];
+	return port->line == -1 ? 0 : 0444;
+}
+
+#define EXT_TTY_ATTR_RO(_name, _val)			\
+	struct dev_ext_attribute dev_attr_tty##_name =	\
+		{ __ATTR(tty##_name, 0444, ptp_ocp_tty_show, NULL), (void *)_val }
+
+static EXT_TTY_ATTR_RO(GNSS, PORT_GNSS);
+static EXT_TTY_ATTR_RO(GNSS2, PORT_GNSS2);
+static EXT_TTY_ATTR_RO(MAC, PORT_MAC);
+static EXT_TTY_ATTR_RO(NMEA, PORT_NMEA);
+static struct attribute *ptp_ocp_timecard_tty_attrs[] = {
+	&dev_attr_ttyGNSS.attr.attr,
+	&dev_attr_ttyGNSS2.attr.attr,
+	&dev_attr_ttyMAC.attr.attr,
+	&dev_attr_ttyNMEA.attr.attr,
+	NULL,
+};
+
+static const struct attribute_group ptp_ocp_timecard_tty_group = {
+	.name = "tty",
+	.attrs = ptp_ocp_timecard_tty_attrs,
+	.is_visible = ptp_ocp_timecard_tty_is_visible,
+};
+
 static ssize_t
 serialnum_show(struct device *dev, struct device_attribute *attr, char *buf)
 {
@@ -3775,6 +3838,7 @@  static const struct attribute_group fb_timecard_group = {
 
 static const struct ocp_attr_group fb_timecard_groups[] = {
 	{ .cap = OCP_CAP_BASIC,	    .group = &fb_timecard_group },
+	{ .cap = OCP_CAP_BASIC,	    .group = &ptp_ocp_timecard_tty_group },
 	{ .cap = OCP_CAP_SIGNAL,    .group = &fb_timecard_signal0_group },
 	{ .cap = OCP_CAP_SIGNAL,    .group = &fb_timecard_signal1_group },
 	{ .cap = OCP_CAP_SIGNAL,    .group = &fb_timecard_signal2_group },
@@ -3814,6 +3878,7 @@  static const struct attribute_group art_timecard_group = {
 
 static const struct ocp_attr_group art_timecard_groups[] = {
 	{ .cap = OCP_CAP_BASIC,	    .group = &art_timecard_group },
+	{ .cap = OCP_CAP_BASIC,	    .group = &ptp_ocp_timecard_tty_group },
 	{ },
 };
 
@@ -3841,6 +3906,7 @@  static const struct attribute_group adva_timecard_group = {
 
 static const struct ocp_attr_group adva_timecard_groups[] = {
 	{ .cap = OCP_CAP_BASIC,	    .group = &adva_timecard_group },
+	{ .cap = OCP_CAP_BASIC,	    .group = &ptp_ocp_timecard_tty_group },
 	{ .cap = OCP_CAP_SIGNAL,    .group = &fb_timecard_signal0_group },
 	{ .cap = OCP_CAP_SIGNAL,    .group = &fb_timecard_signal1_group },
 	{ .cap = OCP_CAP_FREQ,	    .group = &fb_timecard_freq0_group },
@@ -3960,16 +4026,11 @@  ptp_ocp_summary_show(struct seq_file *s, void *data)
 	bp = dev_get_drvdata(dev);
 
 	seq_printf(s, "%7s: /dev/ptp%d\n", "PTP", ptp_clock_index(bp->ptp));
-	if (bp->gnss_port.line != -1)
-		seq_printf(s, "%7s: /dev/ttyS%d\n", "GNSS1",
-			   bp->gnss_port.line);
-	if (bp->gnss2_port.line != -1)
-		seq_printf(s, "%7s: /dev/ttyS%d\n", "GNSS2",
-			   bp->gnss2_port.line);
-	if (bp->mac_port.line != -1)
-		seq_printf(s, "%7s: /dev/ttyS%d\n", "MAC", bp->mac_port.line);
-	if (bp->nmea_port.line != -1)
-		seq_printf(s, "%7s: /dev/ttyS%d\n", "NMEA", bp->nmea_port.line);
+	for (i = 0; i < __PORT_COUNT; i++) {
+		if (bp->port[i].line != -1)
+			seq_printf(s, "%7s: /dev/ttyS%d\n", ptp_ocp_tty_port_name(i),
+				   bp->port[i].line);
+	}
 
 	memset(sma_val, 0xff, sizeof(sma_val));
 	if (bp->sma_map1) {
@@ -4279,7 +4340,7 @@  ptp_ocp_dev_release(struct device *dev)
 static int
 ptp_ocp_device_init(struct ptp_ocp *bp, struct pci_dev *pdev)
 {
-	int err;
+	int i, err;
 
 	mutex_lock(&ptp_ocp_lock);
 	err = idr_alloc(&ptp_ocp_idr, bp, 0, 0, GFP_KERNEL);
@@ -4292,10 +4353,10 @@  ptp_ocp_device_init(struct ptp_ocp *bp, struct pci_dev *pdev)
 
 	bp->ptp_info = ptp_ocp_clock_info;
 	spin_lock_init(&bp->lock);
-	bp->gnss_port.line = -1;
-	bp->gnss2_port.line = -1;
-	bp->mac_port.line = -1;
-	bp->nmea_port.line = -1;
+
+	for (i = 0; i < __PORT_COUNT; i++)
+		bp->port[i].line = -1;
+
 	bp->pdev = pdev;
 
 	device_initialize(&bp->dev);
@@ -4352,22 +4413,6 @@  ptp_ocp_complete(struct ptp_ocp *bp)
 	struct pps_device *pps;
 	char buf[32];
 
-	if (bp->gnss_port.line != -1) {
-		sprintf(buf, "ttyS%d", bp->gnss_port.line);
-		ptp_ocp_link_child(bp, buf, "ttyGNSS");
-	}
-	if (bp->gnss2_port.line != -1) {
-		sprintf(buf, "ttyS%d", bp->gnss2_port.line);
-		ptp_ocp_link_child(bp, buf, "ttyGNSS2");
-	}
-	if (bp->mac_port.line != -1) {
-		sprintf(buf, "ttyS%d", bp->mac_port.line);
-		ptp_ocp_link_child(bp, buf, "ttyMAC");
-	}
-	if (bp->nmea_port.line != -1) {
-		sprintf(buf, "ttyS%d", bp->nmea_port.line);
-		ptp_ocp_link_child(bp, buf, "ttyNMEA");
-	}
 	sprintf(buf, "ptp%d", ptp_clock_index(bp->ptp));
 	ptp_ocp_link_child(bp, buf, "ptp");
 
@@ -4416,23 +4461,20 @@  ptp_ocp_info(struct ptp_ocp *bp)
 	};
 	struct device *dev = &bp->pdev->dev;
 	u32 reg;
+	int i;
 
 	ptp_ocp_phc_info(bp);
 
-	ptp_ocp_serial_info(dev, "GNSS", bp->gnss_port.line,
-			    bp->gnss_port.baud);
-	ptp_ocp_serial_info(dev, "GNSS2", bp->gnss2_port.line,
-			    bp->gnss2_port.baud);
-	ptp_ocp_serial_info(dev, "MAC", bp->mac_port.line, bp->mac_port.baud);
-	if (bp->nmea_out && bp->nmea_port.line != -1) {
-		bp->nmea_port.baud = -1;
+	for (i = 0; i < __PORT_COUNT; i++) {
+		if (i == PORT_NMEA && bp->nmea_out && bp->port[PORT_NMEA].line != -1) {
+			bp->port[PORT_NMEA].baud = -1;
 
-		reg = ioread32(&bp->nmea_out->uart_baud);
-		if (reg < ARRAY_SIZE(nmea_baud))
-			bp->nmea_port.baud = nmea_baud[reg];
-
-		ptp_ocp_serial_info(dev, "NMEA", bp->nmea_port.line,
-				    bp->nmea_port.baud);
+			reg = ioread32(&bp->nmea_out->uart_baud);
+			if (reg < ARRAY_SIZE(nmea_baud))
+				bp->port[PORT_NMEA].baud = nmea_baud[reg];
+		}
+		ptp_ocp_serial_info(dev, ptp_ocp_tty_port_name(i), bp->port[i].line,
+				    bp->port[i].baud);
 	}
 }
 
@@ -4441,9 +4483,6 @@  ptp_ocp_detach_sysfs(struct ptp_ocp *bp)
 {
 	struct device *dev = &bp->dev;
 
-	sysfs_remove_link(&dev->kobj, "ttyGNSS");
-	sysfs_remove_link(&dev->kobj, "ttyGNSS2");
-	sysfs_remove_link(&dev->kobj, "ttyMAC");
 	sysfs_remove_link(&dev->kobj, "ptp");
 	sysfs_remove_link(&dev->kobj, "pps");
 }
@@ -4473,14 +4512,9 @@  ptp_ocp_detach(struct ptp_ocp *bp)
 	for (i = 0; i < 4; i++)
 		if (bp->signal_out[i])
 			ptp_ocp_unregister_ext(bp->signal_out[i]);
-	if (bp->gnss_port.line != -1)
-		serial8250_unregister_port(bp->gnss_port.line);
-	if (bp->gnss2_port.line != -1)
-		serial8250_unregister_port(bp->gnss2_port.line);
-	if (bp->mac_port.line != -1)
-		serial8250_unregister_port(bp->mac_port.line);
-	if (bp->nmea_port.line != -1)
-		serial8250_unregister_port(bp->nmea_port.line);
+	for (i = 0; i < __PORT_COUNT; i++)
+		if (bp->port[i].line != -1)
+			serial8250_unregister_port(bp->port[i].line);
 	platform_device_unregister(bp->spi_flash);
 	platform_device_unregister(bp->i2c_ctrl);
 	if (bp->i2c_clk)