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Date: Fri, 26 Oct 2012 11:46:05 +0530 From: Vineet Gupta <Vineet.Gupta1@...opsys.com> To: Greg KH <gregkh@...uxfoundation.org> CC: <alan@...ux.intel.com>, <arc-linux-dev@...opsys.com>, <linux-serial@...r.kernel.org>, <linux-kernel@...r.kernel.org> Subject: Re: [PATCH] serial/arc-uart: Add new driver On Friday 26 October 2012 12:06 AM, Greg KH wrote: > On Thu, Oct 25, 2012 at 12:00:08PM +0530, Vineet.Gupta1@...opsys.com wrote: >> From: Vineet Gupta <vgupta@...opsys.com> >> >> Driver for non-standard on-chip UART, instantiated in the ARC (Synopsys) >> FPGA Boards such as ARCAngel4/ML50x >> >> Signed-off-by: Vineet Gupta <vgupta@...opsys.com> >> --- >> drivers/tty/serial/Kconfig | 25 ++ >> drivers/tty/serial/Makefile | 1 + >> drivers/tty/serial/arc_uart.c | 747 ++++++++++++++++++++++++++++++++++++++ >> include/uapi/linux/serial_core.h | 2 + >> 4 files changed, 775 insertions(+), 0 deletions(-) >> create mode 100644 drivers/tty/serial/arc_uart.c >> >> diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig >> index 2a53be5..efee7fe 100644 >> --- a/drivers/tty/serial/Kconfig >> +++ b/drivers/tty/serial/Kconfig >> @@ -1423,4 +1423,29 @@ config SERIAL_EFM32_UART_CONSOLE >> depends on SERIAL_EFM32_UART=y >> select SERIAL_CORE_CONSOLE >> >> +config SERIAL_ARC >> + bool "ARC UART driver support" >> + select SERIAL_CORE >> + default y >> + help >> + Driver for on-chip UART for ARC(Synopsys) for the legacy >> + FPGA Boards (ML50x/ARCAngel4) > Unless you will break a user's box, NEVER define a default value for a > new configuration option as y. OK ! > And why can't I select this driver as a module? Because it's missing the equivalent of following (plus some more changes) - bool "ARC UART driver support" + tristate "ARC UART driver support" ARC platform (where this driver originates from) always had system console on UART - thus we never had the need for making it a loadable module. But I guess as a matter of principle it nevertheless needs to work - fixed in the next revision ! >> + >> +config SERIAL_ARC_CONSOLE >> + bool >> + select SERIAL_CORE_CONSOLE >> + depends on SERIAL_ARC=y >> + default y >> + help >> + Enable system Console on ARC UART >> + >> +config SERIAL_ARC_NR_PORTS >> + int 'Number of ports' >> + range 1 3 >> + default 1 >> + depends on SERIAL_ARC >> + help >> + Set this to the number of serial ports you want the driver >> + to support. >> + >> endmenu >> diff --git a/drivers/tty/serial/Makefile b/drivers/tty/serial/Makefile >> index 4f694da..df1b998 100644 >> --- a/drivers/tty/serial/Makefile >> +++ b/drivers/tty/serial/Makefile >> @@ -82,3 +82,4 @@ obj-$(CONFIG_SERIAL_XILINX_PS_UART) += xilinx_uartps.o >> obj-$(CONFIG_SERIAL_SIRFSOC) += sirfsoc_uart.o >> obj-$(CONFIG_SERIAL_AR933X) += ar933x_uart.o >> obj-$(CONFIG_SERIAL_EFM32_UART) += efm32-uart.o >> +obj-$(CONFIG_SERIAL_ARC) += arc_uart.o >> diff --git a/drivers/tty/serial/arc_uart.c b/drivers/tty/serial/arc_uart.c >> new file mode 100644 >> index 0000000..9215bf4 >> --- /dev/null >> +++ b/drivers/tty/serial/arc_uart.c >> @@ -0,0 +1,747 @@ >> +/* >> + * ARC On-Chip(fpga) UART Driver >> + * >> + * Copyright (C) 2010-2012 Synopsys, Inc. (www.synopsys.com) >> + * >> + * This program is free software; you can redistribute it and/or modify >> + * it under the terms of the GNU General Public License version 2 as >> + * published by the Free Software Foundation. >> + * >> + * vineetg: July 10th 2012 >> + * -Decoupled the driver from arch/arc >> + * +Using platform_get_resource() for irq/membase (thx to bfin_uart.c) >> + * +Using early_platform_xxx() for early console (thx to mach-shmobile/xxx) >> + * >> + * Vineetg: Aug 21st 2010 >> + * -Is uart_tx_stopped() not done in tty write path as it has already been >> + * taken care of, in serial core >> + * >> + * Vineetg: Aug 18th 2010 >> + * -New Serial Core based ARC UART driver >> + * -Derived largely from blackfin driver albiet with some major tweaks >> + * >> + * TODO: >> + * -check if sysreq works >> + */ >> + >> +#if defined(CONFIG_SERIAL_ARC_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ) >> +#define SUPPORT_SYSRQ >> +#endif > Are you sure this works? Don't you usually need to include some .h > files before you check these config values? We've been using the exact same driver for years - literally. AFAIK, all the CONFIG_xxx items come in from generated autoconf.h which is included implicitly by build system via cmd line based -include kconfig.h, thus any explicit header is not needed for them. Also SUPPORT_SYSRQ needs to be defined BEFORE including any header because that is the way serial_core.h build can be influenced in a non-ambiguous way. >> + >> +#include <linux/module.h> >> +#include <linux/serial.h> >> +#include <linux/console.h> >> +#include <linux/sysrq.h> >> +#include <linux/platform_device.h> >> +#include <linux/tty.h> >> +#include <linux/tty_flip.h> >> +#include <linux/serial_core.h> >> +#include <linux/io.h> >> + >> +/************************************* >> + * ARC UART Hardware Specs >> + ************************************/ >> +#define ARC_UART_TX_FIFO_SIZE 1 >> + >> +/* >> + * UART Register set (this is not a Standards Compliant IP) >> + * Also each reg is Word aligned, but only 8 bits wide >> + */ >> +#define R_ID0 0 >> +#define R_ID1 1 >> +#define R_ID2 2 >> +#define R_ID3 3 >> +#define R_DATA 4 >> +#define R_STS 5 >> +#define R_BAUDL 6 >> +#define R_BAUDH 7 >> + >> +/* Bits for UART Status Reg (R/W) */ >> +#define RXIENB 0x04 /* Receive Interrupt Enable */ >> +#define TXIENB 0x40 /* Transmit Interrupt Enable */ >> + >> +#define RXEMPTY 0x20 /* Receive FIFO Empty: No char receivede */ >> +#define TXEMPTY 0x80 /* Transmit FIFO Empty, thus char can be written into */ >> + >> +#define RXFULL 0x08 /* Receive FIFO full */ >> +#define RXFULL1 0x10 /* Receive FIFO has space for 1 char (tot space=4) */ >> + >> +#define RXFERR 0x01 /* Frame Error: Stop Bit not detected */ >> +#define RXOERR 0x02 /* OverFlow Err: Char recv but RXFULL still set */ >> + >> +/* Uart bit fiddling helpers: lowest level */ >> +#define RBASE(uart, reg) ((unsigned int *)uart->port.membase + reg) >> +#define UART_REG_SET(u, r, v) writeb((v), RBASE(u, r)) >> +#define UART_REG_GET(u, r) readb(RBASE(u, r)) > What happens when you run sparse on this driver? (1) The cast was indeed causing warning - that's now fixed, with an equivalent of following: -#define R_ID1 1 -#define R_ID2 2 -#define R_ID3 3 -#define R_DATA 4 -#define R_STS 5 -#define R_BAUDL 6 -#define R_BAUDH 7 +#define R_ID1 4 +#define R_ID2 8 +#define R_ID3 12 +#define R_DATA 16 +#define R_STS 20 +#define R_BAUDL 24 +#define R_BAUDH 28 -#define RBASE(uart, reg) ((unsigned int *)uart->port.membase + reg) +#define RBASE(uart, reg) (uart->port.membase + reg) (2) Other two seem to be false warnings for imbalance of spin_lock_irqsave/restore, which otherwise seem OK to me! > > thanks, > > greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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