[v4,33/41] tty: serial: handle HAS_IOPORT dependencies

Message ID 20230516110038.2413224-34-schnelle@linux.ibm.com
State New
Headers
Series treewide: Remove I/O port accessors for HAS_IOPORT=n |

Commit Message

Niklas Schnelle May 16, 2023, 11 a.m. UTC
  In a future patch HAS_IOPORT=n will result in inb()/outb() and friends
not being declared. We thus need to add HAS_IOPORT as dependency for
those drivers using them unconditionally. For 8250 based drivers some
support MMIO only use so fence only the parts requiring I/O ports.

Co-developed-by: Arnd Bergmann <arnd@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@kernel.org>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
---
Note: The HAS_IOPORT Kconfig option was added in v6.4-rc1 so
      per-subsystem patches may be applied independently

 drivers/tty/Kconfig                  |  4 +--
 drivers/tty/serial/8250/8250_early.c |  4 +++
 drivers/tty/serial/8250/8250_pci.c   | 14 +++++++++
 drivers/tty/serial/8250/8250_port.c  | 44 +++++++++++++++++++++++-----
 drivers/tty/serial/8250/Kconfig      |  5 ++--
 drivers/tty/serial/Kconfig           |  2 +-
 6 files changed, 60 insertions(+), 13 deletions(-)
  

Comments

Greg KH May 30, 2023, 10:48 a.m. UTC | #1
On Tue, May 16, 2023 at 01:00:29PM +0200, Niklas Schnelle wrote:
> In a future patch HAS_IOPORT=n will result in inb()/outb() and friends
> not being declared. We thus need to add HAS_IOPORT as dependency for
> those drivers using them unconditionally. For 8250 based drivers some
> support MMIO only use so fence only the parts requiring I/O ports.

Why can't you have dummy inb()/outb() so we don't need these #ifdefs all
over the place in .c files?  Was that documented somewhere?  We do that
for other driver/hardware apis, why are these so special they don't
deserve that?

Otherwise this makes old drivers really messy with these additional
#ifdefs, something we never wanted to do in .c files.

thanks,

greg k-h
  
Arnd Bergmann May 30, 2023, 11:53 a.m. UTC | #2
On Tue, May 30, 2023, at 12:48, Greg Kroah-Hartman wrote:
> On Tue, May 16, 2023 at 01:00:29PM +0200, Niklas Schnelle wrote:
>> In a future patch HAS_IOPORT=n will result in inb()/outb() and friends
>> not being declared. We thus need to add HAS_IOPORT as dependency for
>> those drivers using them unconditionally. For 8250 based drivers some
>> support MMIO only use so fence only the parts requiring I/O ports.
>
> Why can't you have dummy inb()/outb() so we don't need these #ifdefs all
> over the place in .c files?  Was that documented somewhere?  We do that
> for other driver/hardware apis, why are these so special they don't
> deserve that?

That was what our original approach did years ago, and Linus rightfully
rejected it. Almost every driver either requires inb()/outb() to do
anything, or it doesn't use them at all. The 8250 uart is one of the
few exceptions to this, as it has many variants.
It would be possible to separate this out more in the 8250 driver
as well and split it out into separate modules and indirect function
pointers, but that would be a larger rework and have a higher
risk of regressions.

Also, the 8250 driver is already full of #ifdef in .c files, 

    Arnd
  
Greg KH May 30, 2023, 2:31 p.m. UTC | #3
On Tue, May 30, 2023 at 01:53:50PM +0200, Arnd Bergmann wrote:
> On Tue, May 30, 2023, at 12:48, Greg Kroah-Hartman wrote:
> > On Tue, May 16, 2023 at 01:00:29PM +0200, Niklas Schnelle wrote:
> >> In a future patch HAS_IOPORT=n will result in inb()/outb() and friends
> >> not being declared. We thus need to add HAS_IOPORT as dependency for
> >> those drivers using them unconditionally. For 8250 based drivers some
> >> support MMIO only use so fence only the parts requiring I/O ports.
> >
> > Why can't you have dummy inb()/outb() so we don't need these #ifdefs all
> > over the place in .c files?  Was that documented somewhere?  We do that
> > for other driver/hardware apis, why are these so special they don't
> > deserve that?
> 
> That was what our original approach did years ago, and Linus rightfully
> rejected it. Almost every driver either requires inb()/outb() to do
> anything, or it doesn't use them at all. The 8250 uart is one of the
> few exceptions to this, as it has many variants.
> It would be possible to separate this out more in the 8250 driver
> as well and split it out into separate modules and indirect function
> pointers, but that would be a larger rework and have a higher
> risk of regressions.
> 
> Also, the 8250 driver is already full of #ifdef in .c files, 

Yeah, just trying to hope it could be better :(

Ok, I'll go queue up the v5 version of this patch now, thanks.

greg k-h
  

Patch

diff --git a/drivers/tty/Kconfig b/drivers/tty/Kconfig
index 341abaed4ce2..bdd267dbd5e4 100644
--- a/drivers/tty/Kconfig
+++ b/drivers/tty/Kconfig
@@ -222,7 +222,7 @@  config MOXA_INTELLIO
 
 config MOXA_SMARTIO
 	tristate "Moxa SmartIO support v. 2.0"
-	depends on SERIAL_NONSTANDARD && PCI
+	depends on SERIAL_NONSTANDARD && PCI && HAS_IOPORT
 	help
 	  Say Y here if you have a Moxa SmartIO multiport serial card and/or
 	  want to help develop a new version of this driver.
@@ -303,7 +303,7 @@  config GOLDFISH_TTY_EARLY_CONSOLE
 
 config IPWIRELESS
 	tristate "IPWireless 3G UMTS PCMCIA card support"
-	depends on PCMCIA && NETDEVICES
+	depends on PCMCIA && NETDEVICES && HAS_IOPORT
 	select PPP
 	help
 	  This is a driver for 3G UMTS PCMCIA card from IPWireless company. In
diff --git a/drivers/tty/serial/8250/8250_early.c b/drivers/tty/serial/8250/8250_early.c
index 0ebde0ab8167..4192b1ae2736 100644
--- a/drivers/tty/serial/8250/8250_early.c
+++ b/drivers/tty/serial/8250/8250_early.c
@@ -48,8 +48,10 @@  static unsigned int serial8250_early_in(struct uart_port *port, int offset)
 		return readl(port->membase + offset);
 	case UPIO_MEM32BE:
 		return ioread32be(port->membase + offset);
+#ifdef CONFIG_HAS_IOPORT
 	case UPIO_PORT:
 		return inb(port->iobase + offset);
+#endif
 	case UPIO_AU:
 		return port->serial_in(port, reg_offset);
 	default:
@@ -75,9 +77,11 @@  static void serial8250_early_out(struct uart_port *port, int offset, int value)
 	case UPIO_MEM32BE:
 		iowrite32be(value, port->membase + offset);
 		break;
+#ifdef CONFIG_HAS_IOPORT
 	case UPIO_PORT:
 		outb(value, port->iobase + offset);
 		break;
+#endif
 	case UPIO_AU:
 		port->serial_out(port, reg_offset, value);
 		break;
diff --git a/drivers/tty/serial/8250/8250_pci.c b/drivers/tty/serial/8250/8250_pci.c
index c55be6fda0ca..70bd84a05da7 100644
--- a/drivers/tty/serial/8250/8250_pci.c
+++ b/drivers/tty/serial/8250/8250_pci.c
@@ -847,6 +847,7 @@  static int pci_netmos_init(struct pci_dev *dev)
 	return num_serial;
 }
 
+#ifdef CONFIG_HAS_IOPORT
 /*
  * These chips are available with optionally one parallel port and up to
  * two serial ports. Unfortunately they all have the same product id.
@@ -973,6 +974,7 @@  static void pci_ite887x_exit(struct pci_dev *dev)
 	ioport &= 0xffff;
 	release_region(ioport, ITE_887x_IOSIZE);
 }
+#endif /* CONFIG_HAS_IOPORT */
 
 /*
  * Oxford Semiconductor Inc.
@@ -1255,6 +1257,7 @@  static int pci_asix_setup(struct serial_private *priv,
 #define QOPR_CLOCK_X8		0x0003
 #define QOPR_CLOCK_RATE_MASK	0x0003
 
+#ifdef CONFIG_HAS_IOPORT
 /* Quatech devices have their own extra interface features */
 static struct pci_device_id quatech_cards[] = {
 	{ PCI_DEVICE_DATA(QUATECH, QSC100,   1) },
@@ -1474,6 +1477,7 @@  static int pci_quatech_setup(struct serial_private *priv,
 		pci_warn(priv->dev, "software control of RS422 features not currently supported.\n");
 	return pci_default_setup(priv, board, port, idx);
 }
+#endif /* CONFIG_HAS_IOPORT */
 
 static int pci_default_setup(struct serial_private *priv,
 		  const struct pciserial_board *board,
@@ -1753,6 +1757,7 @@  static int skip_tx_en_setup(struct serial_private *priv,
 	return pci_default_setup(priv, board, port, idx);
 }
 
+#ifdef CONFIG_HAS_IOPORT
 static void kt_handle_break(struct uart_port *p)
 {
 	struct uart_8250_port *up = up_to_u8250p(p);
@@ -1796,6 +1801,7 @@  static int kt_serial_setup(struct serial_private *priv,
 	port->port.handle_break = kt_handle_break;
 	return skip_tx_en_setup(priv, board, port, idx);
 }
+#endif /* CONFIG_HAS_IOPORT */
 
 static int pci_eg20t_init(struct pci_dev *dev)
 {
@@ -1840,6 +1846,7 @@  pci_wch_ch38x_setup(struct serial_private *priv,
 #define CH384_XINT_ENABLE_REG   0xEB
 #define CH384_XINT_ENABLE_BIT   0x02
 
+#ifdef CONFIG_HAS_IOPORT
 static int pci_wch_ch38x_init(struct pci_dev *dev)
 {
 	int max_port;
@@ -1867,6 +1874,7 @@  static void pci_wch_ch38x_exit(struct pci_dev *dev)
 	iobase = pci_resource_start(dev, 0);
 	outb(0x0, iobase + CH384_XINT_ENABLE_REG);
 }
+#endif /* CONFIG_HAS_IOPORT */
 
 
 static int
@@ -2070,6 +2078,7 @@  static struct pci_serial_quirk pci_serial_quirks[] = {
 		.subdevice	= PCI_ANY_ID,
 		.setup		= ce4100_serial_setup,
 	},
+#ifdef CONFIG_HAS_IOPORT
 	{
 		.vendor		= PCI_VENDOR_ID_INTEL,
 		.device		= PCI_DEVICE_ID_INTEL_PATSBURG_KT,
@@ -2089,6 +2098,7 @@  static struct pci_serial_quirk pci_serial_quirks[] = {
 		.setup		= pci_default_setup,
 		.exit		= pci_ite887x_exit,
 	},
+#endif
 	/*
 	 * National Instruments
 	 */
@@ -2210,6 +2220,7 @@  static struct pci_serial_quirk pci_serial_quirks[] = {
 		.exit		= pci_ni8430_exit,
 	},
 	/* Quatech */
+#ifdef CONFIG_HAS_IOPORT
 	{
 		.vendor		= PCI_VENDOR_ID_QUATECH,
 		.device		= PCI_ANY_ID,
@@ -2218,6 +2229,7 @@  static struct pci_serial_quirk pci_serial_quirks[] = {
 		.init		= pci_quatech_init,
 		.setup		= pci_quatech_setup,
 	},
+#endif
 	/*
 	 * Panacom
 	 */
@@ -2588,6 +2600,7 @@  static struct pci_serial_quirk pci_serial_quirks[] = {
 		.subdevice      = PCI_ANY_ID,
 		.setup          = pci_wch_ch38x_setup,
 	},
+#ifdef CONFIG_HAS_IOPORT
 	/* WCH CH384 8S card (16850 clone) */
 	{
 		.vendor         = PCIE_VENDOR_ID_WCH,
@@ -2598,6 +2611,7 @@  static struct pci_serial_quirk pci_serial_quirks[] = {
 		.exit		= pci_wch_ch38x_exit,
 		.setup          = pci_wch_ch38x_setup,
 	},
+#endif
 	/*
 	 * ASIX devices with FIFO bug
 	 */
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index fe8d79c4ae95..8d8606dc763b 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -401,6 +401,7 @@  static void au_serial_dl_write(struct uart_8250_port *up, int value)
 
 #endif
 
+#ifdef CONFIG_HAS_IOPORT
 static unsigned int hub6_serial_in(struct uart_port *p, int offset)
 {
 	offset = offset << p->regshift;
@@ -414,6 +415,7 @@  static void hub6_serial_out(struct uart_port *p, int offset, int value)
 	outb(p->hub6 - 1 + offset, p->iobase);
 	outb(value, p->iobase + 1);
 }
+#endif /* CONFIG_HAS_IOPORT */
 
 static unsigned int mem_serial_in(struct uart_port *p, int offset)
 {
@@ -463,6 +465,7 @@  static unsigned int mem32be_serial_in(struct uart_port *p, int offset)
 	return ioread32be(p->membase + offset);
 }
 
+#ifdef CONFIG_HAS_IOPORT
 static unsigned int io_serial_in(struct uart_port *p, int offset)
 {
 	offset = offset << p->regshift;
@@ -474,6 +477,24 @@  static void io_serial_out(struct uart_port *p, int offset, int value)
 	offset = offset << p->regshift;
 	outb(value, p->iobase + offset);
 }
+#endif
+static unsigned int no_serial_in(struct uart_port *p, int offset)
+{
+	return (unsigned int)-1;
+}
+
+static void no_serial_out(struct uart_port *p, int offset, int value)
+{
+}
+
+#ifdef CONFIG_HAS_IOPORT
+static inline bool is_upf_fourport(struct uart_port *port)
+{
+	return port->flags & UPF_FOURPORT;
+}
+#else
+#define is_upf_fourport(x)	false
+#endif
 
 static int serial8250_default_handle_irq(struct uart_port *port);
 
@@ -485,10 +506,12 @@  static void set_io_from_upio(struct uart_port *p)
 	up->dl_write = default_serial_dl_write;
 
 	switch (p->iotype) {
+#ifdef CONFIG_HAS_IOPORT
 	case UPIO_HUB6:
 		p->serial_in = hub6_serial_in;
 		p->serial_out = hub6_serial_out;
 		break;
+#endif
 
 	case UPIO_MEM:
 		p->serial_in = mem_serial_in;
@@ -519,10 +542,17 @@  static void set_io_from_upio(struct uart_port *p)
 		break;
 #endif
 
-	default:
+#ifdef CONFIG_HAS_IOPORT
+	case UPIO_PORT:
 		p->serial_in = io_serial_in;
 		p->serial_out = io_serial_out;
 		break;
+#endif
+
+	default:
+		WARN(1, "Unsupported UART type %x\n", p->iotype);
+		p->serial_in = no_serial_in;
+		p->serial_out = no_serial_out;
 	}
 	/* Remember loaded iotype */
 	up->cur_iotype = p->iotype;
@@ -1379,7 +1409,7 @@  static void autoconfig_irq(struct uart_8250_port *up)
 	unsigned long irqs;
 	int irq;
 
-	if (port->flags & UPF_FOURPORT) {
+	if (is_upf_fourport(port)) {
 		ICP = (port->iobase & 0xfe0) | 0x1f;
 		save_ICP = inb_p(ICP);
 		outb_p(0x80, ICP);
@@ -1398,7 +1428,7 @@  static void autoconfig_irq(struct uart_8250_port *up)
 	irqs = probe_irq_on();
 	serial8250_out_MCR(up, 0);
 	udelay(10);
-	if (port->flags & UPF_FOURPORT) {
+	if (is_upf_fourport(port)) {
 		serial8250_out_MCR(up, UART_MCR_DTR | UART_MCR_RTS);
 	} else {
 		serial8250_out_MCR(up,
@@ -1416,7 +1446,7 @@  static void autoconfig_irq(struct uart_8250_port *up)
 	serial8250_out_MCR(up, save_mcr);
 	serial_out(up, UART_IER, save_ier);
 
-	if (port->flags & UPF_FOURPORT)
+	if (is_upf_fourport(port))
 		outb_p(save_ICP, ICP);
 
 	if (uart_console(port))
@@ -2381,7 +2411,7 @@  int serial8250_do_startup(struct uart_port *port)
 	serial_port_out(port, UART_LCR, UART_LCR_WLEN8);
 
 	spin_lock_irqsave(&port->lock, flags);
-	if (up->port.flags & UPF_FOURPORT) {
+	if (is_upf_fourport(&up->port)) {
 		if (!up->port.irq)
 			up->port.mctrl |= TIOCM_OUT1;
 	} else
@@ -2463,7 +2493,7 @@  int serial8250_do_startup(struct uart_port *port)
 	 */
 	up->ier = UART_IER_RLSI | UART_IER_RDI;
 
-	if (port->flags & UPF_FOURPORT) {
+	if (is_upf_fourport(port)) {
 		unsigned int icp;
 		/*
 		 * Enable interrupts on the AST Fourport board
@@ -2506,7 +2536,7 @@  void serial8250_do_shutdown(struct uart_port *port)
 		serial8250_release_dma(up);
 
 	spin_lock_irqsave(&port->lock, flags);
-	if (port->flags & UPF_FOURPORT) {
+	if (is_upf_fourport(port)) {
 		/* reset interrupts on the AST Fourport board */
 		inb((port->iobase & 0xfe0) | 0x1f);
 		port->mctrl |= TIOCM_OUT1;
diff --git a/drivers/tty/serial/8250/Kconfig b/drivers/tty/serial/8250/Kconfig
index 5313aa31930f..2a43bea7d7c3 100644
--- a/drivers/tty/serial/8250/Kconfig
+++ b/drivers/tty/serial/8250/Kconfig
@@ -6,7 +6,6 @@ 
 
 config SERIAL_8250
 	tristate "8250/16550 and compatible serial support"
-	depends on !S390
 	select SERIAL_CORE
 	select SERIAL_MCTRL_GPIO if GPIOLIB
 	help
@@ -72,7 +71,7 @@  config SERIAL_8250_16550A_VARIANTS
 
 config SERIAL_8250_FINTEK
 	bool "Support for Fintek F81216A LPC to 4 UART RS485 API"
-	depends on SERIAL_8250
+	depends on SERIAL_8250 && HAS_IOPORT
 	help
 	  Selecting this option will add support for the RS485 capabilities
 	  of the Fintek F81216A LPC to 4 UART.
@@ -160,7 +159,7 @@  config SERIAL_8250_HP300
 
 config SERIAL_8250_CS
 	tristate "8250/16550 PCMCIA device support"
-	depends on PCMCIA && SERIAL_8250
+	depends on PCMCIA && SERIAL_8250 && HAS_IOPORT
 	help
 	  Say Y here to enable support for 16-bit PCMCIA serial devices,
 	  including serial port cards, modems, and the modem functions of
diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index 398e5aac2e77..dc41b3be6800 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -871,7 +871,7 @@  config SERIAL_TXX9_STDSERIAL
 
 config SERIAL_JSM
 	tristate "Digi International NEO and Classic PCI Support"
-	depends on PCI
+	depends on PCI && HAS_IOPORT
 	select SERIAL_CORE
 	help
 	  This is a driver for Digi International's Neo and Classic series