Message-ID: <20250723115823.76341-1-tsbogend@alpha.franken.de>
Date: Wed, 23 Jul 2025 13:58:23 +0200
From: Thomas Bogendoerfer <tsbogend@...ha.franken.de>
To: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Jiri Slaby <jirislaby@...nel.org>,
	linux-mips@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	linux-serial@...r.kernel.org
Subject: [PATCH] tty: serial: ip22zilog: Use platform device for probing

After commit 84a9582fd203 ("serial: core: Start managing serial controllers
to enable runtime PM") serial drivers need to provide a device in
struct uart_port.dev otherwise an oops happens. To fix this issue
for ip22zilog driver switch driver to a platform driver and setup
the serial device in sgi-ip22 code.

Signed-off-by: Thomas Bogendoerfer <tsbogend@...ha.franken.de>
---
 arch/mips/sgi-ip22/ip22-platform.c |  39 ++++
 drivers/tty/serial/ip22zilog.c     | 360 ++++++++++++-----------------
 2 files changed, 186 insertions(+), 213 deletions(-)

diff --git a/arch/mips/sgi-ip22/ip22-platform.c b/arch/mips/sgi-ip22/ip22-platform.c
index 0b2002e02a47..592b7f4085d9 100644
--- a/arch/mips/sgi-ip22/ip22-platform.c
+++ b/arch/mips/sgi-ip22/ip22-platform.c
@@ -221,3 +221,42 @@ static int __init sgi_ds1286_devinit(void)
 }
 
 device_initcall(sgi_ds1286_devinit);
+
+#define SGI_ZILOG_BASE	(HPC3_CHIP0_BASE + \
+			 offsetof(struct hpc3_regs, pbus_extregs[6]) + \
+			 offsetof(struct sgioc_regs, uart))
+
+static struct resource sgi_zilog_resources[] = {
+	{
+		.start	= SGI_ZILOG_BASE,
+		.end	= SGI_ZILOG_BASE + 15,
+		.flags	= IORESOURCE_MEM
+	},
+	{
+		.start	= SGI_SERIAL_IRQ,
+		.end	= SGI_SERIAL_IRQ,
+		.flags	= IORESOURCE_IRQ
+	}
+};
+
+static struct platform_device zilog_device = {
+	.name		= "ip22zilog",
+	.id		= 0,
+	.num_resources	= ARRAY_SIZE(sgi_zilog_resources),
+	.resource	= sgi_zilog_resources,
+};
+
+
+static int __init sgi_zilog_devinit(void)
+{
+	struct resource res;
+
+	memset(&res, 0, sizeof(res));
+	res.start = HPC3_CHIP0_BASE + offsetof(struct hpc3_regs, rtcregs);
+	res.end = res.start + sizeof(hpc3c0->rtcregs) - 1;
+	res.flags = IORESOURCE_MEM;
+
+	return platform_device_register(&zilog_device);
+}
+
+device_initcall(sgi_zilog_devinit);
diff --git a/drivers/tty/serial/ip22zilog.c b/drivers/tty/serial/ip22zilog.c
index c2cae50f06f3..6e19c6713849 100644
--- a/drivers/tty/serial/ip22zilog.c
+++ b/drivers/tty/serial/ip22zilog.c
@@ -30,6 +30,7 @@
 #include <linux/console.h>
 #include <linux/spinlock.h>
 #include <linux/init.h>
+#include <linux/platform_device.h>
 
 #include <linux/io.h>
 #include <asm/irq.h>
@@ -50,8 +51,9 @@
 #define ZSDELAY_LONG()		udelay(20)
 #define ZS_WSYNC(channel)	do { } while (0)
 
-#define NUM_IP22ZILOG		1
-#define NUM_CHANNELS		(NUM_IP22ZILOG * 2)
+#define NUM_CHANNELS		2
+#define CHANNEL_B		0
+#define CHANNEL_A		1
 
 #define ZS_CLOCK		3672000	/* Zilog input clock rate. */
 #define ZS_CLOCK_DIVISOR	16      /* Divisor this driver uses. */
@@ -62,9 +64,6 @@
 struct uart_ip22zilog_port {
 	struct uart_port		port;
 
-	/* IRQ servicing chain.  */
-	struct uart_ip22zilog_port	*next;
-
 	/* Current values of Zilog write registers.  */
 	unsigned char			curregs[NUM_ZSREGS];
 
@@ -72,7 +71,6 @@ struct uart_ip22zilog_port {
 #define IP22ZILOG_FLAG_IS_CONS		0x00000004
 #define IP22ZILOG_FLAG_IS_KGDB		0x00000008
 #define IP22ZILOG_FLAG_MODEM_STATUS	0x00000010
-#define IP22ZILOG_FLAG_IS_CHANNEL_A	0x00000020
 #define IP22ZILOG_FLAG_REGS_HELD	0x00000040
 #define IP22ZILOG_FLAG_TX_STOPPED	0x00000080
 #define IP22ZILOG_FLAG_TX_ACTIVE	0x00000100
@@ -84,6 +82,8 @@ struct uart_ip22zilog_port {
 	unsigned char			prev_status;
 };
 
+static struct uart_ip22zilog_port ip22zilog_port_table[NUM_CHANNELS];
+
 #define ZILOG_CHANNEL_FROM_PORT(PORT)	((struct zilog_channel *)((PORT)->membase))
 #define UART_ZILOG(PORT)		((struct uart_ip22zilog_port *)(PORT))
 #define IP22ZILOG_GET_CURR_REG(PORT, REGNUM)		\
@@ -93,7 +93,6 @@ struct uart_ip22zilog_port {
 #define ZS_IS_CONS(UP)	((UP)->flags & IP22ZILOG_FLAG_IS_CONS)
 #define ZS_IS_KGDB(UP)	((UP)->flags & IP22ZILOG_FLAG_IS_KGDB)
 #define ZS_WANTS_MODEM_STATUS(UP)	((UP)->flags & IP22ZILOG_FLAG_MODEM_STATUS)
-#define ZS_IS_CHANNEL_A(UP)	((UP)->flags & IP22ZILOG_FLAG_IS_CHANNEL_A)
 #define ZS_REGS_HELD(UP)	((UP)->flags & IP22ZILOG_FLAG_REGS_HELD)
 #define ZS_TX_STOPPED(UP)	((UP)->flags & IP22ZILOG_FLAG_TX_STOPPED)
 #define ZS_TX_ACTIVE(UP)	((UP)->flags & IP22ZILOG_FLAG_TX_ACTIVE)
@@ -423,60 +422,57 @@ static void ip22zilog_transmit_chars(struct uart_ip22zilog_port *up,
 
 static irqreturn_t ip22zilog_interrupt(int irq, void *dev_id)
 {
-	struct uart_ip22zilog_port *up = dev_id;
+	struct uart_ip22zilog_port *up;
+	struct zilog_channel *channel;
+	unsigned char r3;
+	bool push = false;
 
-	while (up) {
-		struct zilog_channel *channel
-			= ZILOG_CHANNEL_FROM_PORT(&up->port);
-		unsigned char r3;
-		bool push = false;
+	up = &ip22zilog_port_table[CHANNEL_A];
+	channel = ZILOG_CHANNEL_FROM_PORT(&up->port);
 
-		uart_port_lock(&up->port);
-		r3 = read_zsreg(channel, R3);
+	uart_port_lock(&up->port);
+	r3 = read_zsreg(channel, R3);
 
-		/* Channel A */
-		if (r3 & (CHAEXT | CHATxIP | CHARxIP)) {
-			writeb(RES_H_IUS, &channel->control);
-			ZSDELAY();
-			ZS_WSYNC(channel);
+	/* Channel A */
+	if (r3 & (CHAEXT | CHATxIP | CHARxIP)) {
+		writeb(RES_H_IUS, &channel->control);
+		ZSDELAY();
+		ZS_WSYNC(channel);
 
-			if (r3 & CHARxIP)
-				push = ip22zilog_receive_chars(up, channel);
-			if (r3 & CHAEXT)
-				ip22zilog_status_handle(up, channel);
-			if (r3 & CHATxIP)
-				ip22zilog_transmit_chars(up, channel);
-		}
-		uart_port_unlock(&up->port);
-
-		if (push)
-			tty_flip_buffer_push(&up->port.state->port);
-
-		/* Channel B */
-		up = up->next;
-		channel = ZILOG_CHANNEL_FROM_PORT(&up->port);
-		push = false;
-
-		uart_port_lock(&up->port);
-		if (r3 & (CHBEXT | CHBTxIP | CHBRxIP)) {
-			writeb(RES_H_IUS, &channel->control);
-			ZSDELAY();
-			ZS_WSYNC(channel);
-
-			if (r3 & CHBRxIP)
-				push = ip22zilog_receive_chars(up, channel);
-			if (r3 & CHBEXT)
-				ip22zilog_status_handle(up, channel);
-			if (r3 & CHBTxIP)
-				ip22zilog_transmit_chars(up, channel);
-		}
-		uart_port_unlock(&up->port);
-
-		if (push)
-			tty_flip_buffer_push(&up->port.state->port);
-
-		up = up->next;
+		if (r3 & CHARxIP)
+			push = ip22zilog_receive_chars(up, channel);
+		if (r3 & CHAEXT)
+			ip22zilog_status_handle(up, channel);
+		if (r3 & CHATxIP)
+			ip22zilog_transmit_chars(up, channel);
 	}
+	uart_port_unlock(&up->port);
+
+	if (push)
+		tty_flip_buffer_push(&up->port.state->port);
+
+	/* Channel B */
+	up = &ip22zilog_port_table[CHANNEL_B];
+	channel = ZILOG_CHANNEL_FROM_PORT(&up->port);
+	push = false;
+
+	uart_port_lock(&up->port);
+	if (r3 & (CHBEXT | CHBTxIP | CHBRxIP)) {
+		writeb(RES_H_IUS, &channel->control);
+		ZSDELAY();
+		ZS_WSYNC(channel);
+
+		if (r3 & CHBRxIP)
+			push = ip22zilog_receive_chars(up, channel);
+		if (r3 & CHBEXT)
+			ip22zilog_status_handle(up, channel);
+		if (r3 & CHBTxIP)
+			ip22zilog_transmit_chars(up, channel);
+	}
+	uart_port_unlock(&up->port);
+
+	if (push)
+		tty_flip_buffer_push(&up->port.state->port);
 
 	return IRQ_HANDLED;
 }
@@ -692,16 +688,16 @@ static void __ip22zilog_reset(struct uart_ip22zilog_port *up)
 		udelay(100);
 	}
 
-	if (!ZS_IS_CHANNEL_A(up)) {
-		up++;
-		channel = ZILOG_CHANNEL_FROM_PORT(&up->port);
-	}
+	up = &ip22zilog_port_table[CHANNEL_A];
+	channel = ZILOG_CHANNEL_FROM_PORT(&up->port);
+
 	write_zsreg(channel, R9, FHWRES);
 	ZSDELAY_LONG();
 	(void) read_zsreg(channel, R0);
 
 	up->flags |= IP22ZILOG_FLAG_RESET_DONE;
-	up->next->flags |= IP22ZILOG_FLAG_RESET_DONE;
+	up = &ip22zilog_port_table[CHANNEL_B];
+	up->flags |= IP22ZILOG_FLAG_RESET_DONE;
 }
 
 static void __ip22zilog_startup(struct uart_ip22zilog_port *up)
@@ -942,47 +938,6 @@ static const struct uart_ops ip22zilog_pops = {
 	.verify_port	=	ip22zilog_verify_port,
 };
 
-static struct uart_ip22zilog_port *ip22zilog_port_table;
-static struct zilog_layout **ip22zilog_chip_regs;
-
-static struct uart_ip22zilog_port *ip22zilog_irq_chain;
-static int zilog_irq = -1;
-
-static void * __init alloc_one_table(unsigned long size)
-{
-	return kzalloc(size, GFP_KERNEL);
-}
-
-static void __init ip22zilog_alloc_tables(void)
-{
-	ip22zilog_port_table = (struct uart_ip22zilog_port *)
-		alloc_one_table(NUM_CHANNELS * sizeof(struct uart_ip22zilog_port));
-	ip22zilog_chip_regs = (struct zilog_layout **)
-		alloc_one_table(NUM_IP22ZILOG * sizeof(struct zilog_layout *));
-
-	if (ip22zilog_port_table == NULL || ip22zilog_chip_regs == NULL) {
-		panic("IP22-Zilog: Cannot allocate IP22-Zilog tables.");
-	}
-}
-
-/* Get the address of the registers for IP22-Zilog instance CHIP.  */
-static struct zilog_layout * __init get_zs(int chip)
-{
-	unsigned long base;
-
-	if (chip < 0 || chip >= NUM_IP22ZILOG) {
-		panic("IP22-Zilog: Illegal chip number %d in get_zs.", chip);
-	}
-
-	/* Not probe-able, hard code it. */
-	base = (unsigned long) &sgioc->uart;
-
-	zilog_irq = SGI_SERIAL_IRQ;
-	request_mem_region(base, 8, "IP22-Zilog");
-
-	return (struct zilog_layout *) base;
-}
-
 #define ZS_PUT_CHAR_MAX_DELAY	2000	/* 10 ms */
 
 #ifdef CONFIG_SERIAL_IP22_ZILOG_CONSOLE
@@ -1070,144 +1025,123 @@ static struct uart_driver ip22zilog_reg = {
 #endif
 };
 
-static void __init ip22zilog_prepare(void)
+static void __init ip22zilog_prepare(struct uart_ip22zilog_port *up)
 {
 	unsigned char sysrq_on = IS_ENABLED(CONFIG_SERIAL_IP22_ZILOG_CONSOLE);
-	struct uart_ip22zilog_port *up;
-	struct zilog_layout *rp;
-	int channel, chip;
+	int brg;
 
-	/*
-	 * Temporary fix.
-	 */
-	for (channel = 0; channel < NUM_CHANNELS; channel++)
-		spin_lock_init(&ip22zilog_port_table[channel].port.lock);
+	spin_lock_init(&up->port.lock);
 
-	ip22zilog_irq_chain = &ip22zilog_port_table[NUM_CHANNELS - 1];
-        up = &ip22zilog_port_table[0];
-	for (channel = NUM_CHANNELS - 1 ; channel > 0; channel--)
-		up[channel].next = &up[channel - 1];
-	up[channel].next = NULL;
+	up->port.iotype = UPIO_MEM;
+	up->port.uartclk = ZS_CLOCK;
+	up->port.fifosize = 1;
+	up->port.has_sysrq = sysrq_on;
+	up->port.ops = &ip22zilog_pops;
+	up->port.type = PORT_IP22ZILOG;
 
-	for (chip = 0; chip < NUM_IP22ZILOG; chip++) {
-		if (!ip22zilog_chip_regs[chip]) {
-			ip22zilog_chip_regs[chip] = rp = get_zs(chip);
-
-			up[(chip * 2) + 0].port.membase = (char *) &rp->channelB;
-			up[(chip * 2) + 1].port.membase = (char *) &rp->channelA;
-
-			/* In theory mapbase is the physical address ...  */
-			up[(chip * 2) + 0].port.mapbase =
-				(unsigned long) ioremap((unsigned long) &rp->channelB, 8);
-			up[(chip * 2) + 1].port.mapbase =
-				(unsigned long) ioremap((unsigned long) &rp->channelA, 8);
-		}
-
-		/* Channel A */
-		up[(chip * 2) + 0].port.iotype = UPIO_MEM;
-		up[(chip * 2) + 0].port.irq = zilog_irq;
-		up[(chip * 2) + 0].port.uartclk = ZS_CLOCK;
-		up[(chip * 2) + 0].port.fifosize = 1;
-		up[(chip * 2) + 0].port.has_sysrq = sysrq_on;
-		up[(chip * 2) + 0].port.ops = &ip22zilog_pops;
-		up[(chip * 2) + 0].port.type = PORT_IP22ZILOG;
-		up[(chip * 2) + 0].port.flags = 0;
-		up[(chip * 2) + 0].port.line = (chip * 2) + 0;
-		up[(chip * 2) + 0].flags = 0;
-
-		/* Channel B */
-		up[(chip * 2) + 1].port.iotype = UPIO_MEM;
-		up[(chip * 2) + 1].port.irq = zilog_irq;
-		up[(chip * 2) + 1].port.uartclk = ZS_CLOCK;
-		up[(chip * 2) + 1].port.fifosize = 1;
-		up[(chip * 2) + 1].port.has_sysrq = sysrq_on;
-		up[(chip * 2) + 1].port.ops = &ip22zilog_pops;
-		up[(chip * 2) + 1].port.type = PORT_IP22ZILOG;
-		up[(chip * 2) + 1].port.line = (chip * 2) + 1;
-		up[(chip * 2) + 1].flags |= IP22ZILOG_FLAG_IS_CHANNEL_A;
-	}
-
-	for (channel = 0; channel < NUM_CHANNELS; channel++) {
-		struct uart_ip22zilog_port *up = &ip22zilog_port_table[channel];
-		int brg;
-
-		/* Normal serial TTY. */
-		up->parity_mask = 0xff;
-		up->curregs[R1] = EXT_INT_ENAB | INT_ALL_Rx | TxINT_ENAB;
-		up->curregs[R4] = PAR_EVEN | X16CLK | SB1;
-		up->curregs[R3] = RxENAB | Rx8;
-		up->curregs[R5] = TxENAB | Tx8;
-		up->curregs[R9] = NV | MIE;
-		up->curregs[R10] = NRZ;
-		up->curregs[R11] = TCBR | RCBR;
-		brg = BPS_TO_BRG(9600, ZS_CLOCK / ZS_CLOCK_DIVISOR);
-		up->curregs[R12] = (brg & 0xff);
-		up->curregs[R13] = (brg >> 8) & 0xff;
-		up->curregs[R14] = BRENAB;
-	}
+	/* Normal serial TTY. */
+	up->parity_mask = 0xff;
+	up->curregs[R1] = EXT_INT_ENAB | INT_ALL_Rx | TxINT_ENAB;
+	up->curregs[R4] = PAR_EVEN | X16CLK | SB1;
+	up->curregs[R3] = RxENAB | Rx8;
+	up->curregs[R5] = TxENAB | Tx8;
+	up->curregs[R9] = NV | MIE;
+	up->curregs[R10] = NRZ;
+	up->curregs[R11] = TCBR | RCBR;
+	brg = BPS_TO_BRG(9600, ZS_CLOCK / ZS_CLOCK_DIVISOR);
+	up->curregs[R12] = (brg & 0xff);
+	up->curregs[R13] = (brg >> 8) & 0xff;
+	up->curregs[R14] = BRENAB;
 }
 
-static int __init ip22zilog_ports_init(void)
+static int ip22zilog_probe(struct platform_device *pdev)
 {
-	int ret;
+	struct uart_ip22zilog_port *up;
+	char __iomem *membase;
+	struct resource *res;
+	int irq;
+	int i;
 
-	printk(KERN_INFO "Serial: IP22 Zilog driver (%d chips).\n", NUM_IP22ZILOG);
+	up = &ip22zilog_port_table[CHANNEL_B];
+	if (up->port.dev)
+		return -ENOSPC;
 
-	ip22zilog_prepare();
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return irq;
 
-	if (request_irq(zilog_irq, ip22zilog_interrupt, 0,
-			"IP22-Zilog", ip22zilog_irq_chain)) {
+	membase = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
+	if (IS_ERR(membase))
+		return PTR_ERR(membase);
+
+	ip22zilog_prepare(up);
+
+	up->port.mapbase = res->start + offsetof(struct zilog_layout, channelB);
+	up->port.membase = membase + offsetof(struct zilog_layout, channelB);
+	up->port.line = 0;
+	up->port.dev = &pdev->dev;
+	up->port.irq = irq;
+
+	up = &ip22zilog_port_table[CHANNEL_A];
+	ip22zilog_prepare(up);
+
+	up->port.mapbase = res->start + offsetof(struct zilog_layout, channelA);
+	up->port.membase = membase + offsetof(struct zilog_layout, channelA);
+	up->port.line = 1;
+	up->port.dev = &pdev->dev;
+	up->port.irq = irq;
+
+	if (request_irq(irq, ip22zilog_interrupt, 0,
+			"IP22-Zilog", NULL)) {
 		panic("IP22-Zilog: Unable to register zs interrupt handler.\n");
 	}
 
-	ret = uart_register_driver(&ip22zilog_reg);
-	if (ret == 0) {
-		int i;
-
-		for (i = 0; i < NUM_CHANNELS; i++) {
-			struct uart_ip22zilog_port *up = &ip22zilog_port_table[i];
-
-			uart_add_one_port(&ip22zilog_reg, &up->port);
-		}
-	}
-
-	return ret;
-}
-
-static int __init ip22zilog_init(void)
-{
-	/* IP22 Zilog setup is hard coded, no probing to do.  */
-	ip22zilog_alloc_tables();
-	ip22zilog_ports_init();
+	for (i = 0; i < NUM_CHANNELS; i++)
+		uart_add_one_port(&ip22zilog_reg,
+				  &ip22zilog_port_table[i].port);
 
 	return 0;
 }
 
-static void __exit ip22zilog_exit(void)
+static void ip22zilog_remove(struct platform_device *pdev)
 {
 	int i;
-	struct uart_ip22zilog_port *up;
 
 	for (i = 0; i < NUM_CHANNELS; i++) {
-		up = &ip22zilog_port_table[i];
-
-		uart_remove_one_port(&ip22zilog_reg, &up->port);
+		uart_remove_one_port(&ip22zilog_reg,
+				     &ip22zilog_port_table[i].port);
+		ip22zilog_port_table[i].port.dev = NULL;
 	}
+}
 
-	/* Free IO mem */
-	up = &ip22zilog_port_table[0];
-	for (i = 0; i < NUM_IP22ZILOG; i++) {
-		if (up[(i * 2) + 0].port.mapbase) {
-		   iounmap((void*)up[(i * 2) + 0].port.mapbase);
-		   up[(i * 2) + 0].port.mapbase = 0;
-		}
-		if (up[(i * 2) + 1].port.mapbase) {
-			iounmap((void*)up[(i * 2) + 1].port.mapbase);
-			up[(i * 2) + 1].port.mapbase = 0;
-		}
+static struct platform_driver ip22zilog_driver = {
+	.probe	= ip22zilog_probe,
+	.remove	= ip22zilog_remove,
+	.driver	= {
+		.name = "ip22zilog"
 	}
+};
 
+static int __init ip22zilog_init(void)
+{
+	int ret;
+
+	ret = uart_register_driver(&ip22zilog_reg);
+	if (ret)
+		return ret;
+
+	ret = platform_driver_register(&ip22zilog_driver);
+	if (ret)
+		uart_unregister_driver(&ip22zilog_reg);
+
+	return ret;
+
+}
+
+static void __exit ip22zilog_exit(void)
+{
 	uart_unregister_driver(&ip22zilog_reg);
+	platform_driver_unregister(&ip22zilog_driver);
 }
 
 module_init(ip22zilog_init);
-- 
2.43.0

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