From: AMEET M. PARANJAPE <aparanja@redhat.com> Date: Fri, 23 Jan 2009 16:28:12 -0500 Subject: [ppc64] serial_core: define FIXED_PORT flag Message-id: 20090123212700.11116.80247.sendpatchset@squad5-lp1.lab.bos.redhat.com O-Subject: [PATCH RHEL5.4 BZ475621] define FIXED_PORT flag for serial_core Bugzilla: 475621 RH-Acked-by: David Howells <dhowells@redhat.com> RH-Acked-by: Pete Zaitcev <zaitcev@redhat.com> RH-Acked-by: Aristeu Rozanski <aris@redhat.com> RHBZ#: ====== https://bugzilla.redhat.com/show_bug.cgi?id=475621 Description: =========== At present, the serial core always allows setserial in userspace to change the port address, irq and base clock of any serial port. That makes sense for legacy ISA ports, but not for (say) embedded ns16550 compatible serial ports at peculiar addresses. In these cases, the kernel code configuring the ports must know exactly where they are, and their clocking arrangements (which can be unusual on embedded boards). It doesn't make sense for userspace to change these settings. Therefore, this patch defines a UPF_FIXED_PORT flag for the uart_port structure. If this flag is set when the serial port is configured, any attempts to alter the port's type, io address, irq or base clock with setserial are ignored. In addition this patch uses the new flag for on-chip serial ports probed in arch/powerpc/kernel/legacy_serial.c, and for other hard-wired serial ports probed by drivers/serial/of_serial.c. RHEL Version Found: ================ RHEL 5.3 kABI Status: ============ No symbols were harmed. Brew: ===== Built on all platforms. http://brewweb.devel.redhat.com/brew/taskinfo?taskID=1661130 Upstream Status: ================ GIT Commit ID abb4a2390737867353ebafc012d45f2b03f3f944 Test Status: ============ Without this patch the QS2* serial over lan (SOL) console results in a garbled output to the screen. The work around was to provide the 'console=ttyS0,19200' at the linux boot prompt and then changing the /etc/inittab entry to include 'tty:2345:respawn:/sbin/agetty ttyS0 19200 vt100-nav'. With this patch the workaround entries are no longer required and SOL works by default. =============================================================== Ameet Paranjape 978-392-3903 ext 23903 IBM on-site partner Proposed Patch: =============== diff --git a/arch/powerpc/kernel/legacy_serial.c b/arch/powerpc/kernel/legacy_serial.c index dfd2bd6..abf244a 100644 --- a/arch/powerpc/kernel/legacy_serial.c +++ b/arch/powerpc/kernel/legacy_serial.c @@ -114,7 +114,8 @@ static int __init add_legacy_soc_port(struct device_node *np, { u64 addr; u32 *addrp; - upf_t flags = UPF_BOOT_AUTOCONF | UPF_SKIP_TEST | UPF_SHARE_IRQ; + upf_t flags = UPF_BOOT_AUTOCONF | UPF_SKIP_TEST | UPF_SHARE_IRQ + | UPF_FIXED_PORT; struct device_node *tsi = of_get_parent(np); /* We only support ports that have a clock frequency properly diff --git a/drivers/serial/of_serial.c b/drivers/serial/of_serial.c index e2b1f2e..eea02a5 100644 --- a/drivers/serial/of_serial.c +++ b/drivers/serial/of_serial.c @@ -48,7 +48,8 @@ static int __devinit of_platform_serial_setup(struct of_device *ofdev, port->iotype = UPIO_MEM; port->type = type; port->uartclk = *clk; - port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_IOREMAP; + port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_IOREMAP + | UPF_FIXED_PORT; port->dev = &ofdev->dev; port->custom_divisor = *clk / (16 * (*spd)); diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c index 5dc8fce..b80c760 100644 --- a/drivers/serial/serial_core.c +++ b/drivers/serial/serial_core.c @@ -683,19 +683,21 @@ static int uart_set_info(struct uart_state *state, */ mutex_lock(&state->mutex); - change_irq = new_serial.irq != port->irq; + change_irq = !(port->flags & UPF_FIXED_PORT) + && new_serial.irq != port->irq; /* * Since changing the 'type' of the port changes its resource * allocations, we should treat type changes the same as * IO port changes. */ - change_port = new_port != port->iobase || - (unsigned long)new_serial.iomem_base != port->mapbase || - new_serial.hub6 != port->hub6 || - new_serial.io_type != port->iotype || - new_serial.iomem_reg_shift != port->regshift || - new_serial.type != port->type; + change_port = !(port->flags & UPF_FIXED_PORT) + && (new_port != port->iobase || + (unsigned long)new_serial.iomem_base != port->mapbase || + new_serial.hub6 != port->hub6 || + new_serial.io_type != port->iotype || + new_serial.iomem_reg_shift != port->regshift || + new_serial.type != port->type); old_flags = port->flags; new_flags = new_serial.flags; @@ -806,8 +808,10 @@ static int uart_set_info(struct uart_state *state, } } - port->irq = new_serial.irq; - port->uartclk = new_serial.baud_base * 16; + if (change_irq) + port->irq = new_serial.irq; + if (!(port->flags & UPF_FIXED_PORT)) + port->uartclk = new_serial.baud_base * 16; port->flags = (port->flags & ~UPF_CHANGE_MASK) | (new_flags & UPF_CHANGE_MASK); port->custom_divisor = new_serial.custom_divisor; diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h index 3fad04f..00443cd 100644 --- a/include/linux/serial_core.h +++ b/include/linux/serial_core.h @@ -258,6 +258,7 @@ struct uart_port { #define UPF_CONS_FLOW ((__force upf_t) (1 << 23)) #define UPF_SHARE_IRQ ((__force upf_t) (1 << 24)) #define UPF_BOOT_AUTOCONF ((__force upf_t) (1 << 28)) +#define UPF_FIXED_PORT ((__force upf_t) (1 << 29)) #define UPF_DEAD ((__force upf_t) (1 << 30)) #define UPF_IOREMAP ((__force upf_t) (1 << 31))