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Date:	Tue, 9 Oct 2012 13:06:14 -0400
From:	Konrad Rzeszutek Wilk <konrad@...nel.org>
To:	Lv Zheng <lv.zheng@...el.com>
Cc:	Len Brown <len.brown@...el.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	Jason Wessel <jason.wessel@...driver.com>,
	Feng Tang <feng.tang@...el.com>, linux-kernel@...r.kernel.org,
	linux-acpi@...r.kernel.org, x86@...nel.org,
	platform-driver-x86@...r.kernel.org
Subject: Re: [PATCH v5 2/2] ACPI: Add Intel MID SPI early console support.

On Tue, Oct 09, 2012 at 10:37:32AM +0800, Lv Zheng wrote:
> DesignWare SPI UART is used as one of the debug ports on Low Power Intel
> Architecture (LPIA) platforms.  This patch is introduced to support this
> debugging console reported by ACPI DBGP/DBG2.  The original MID SPI
> early console stuff is also refined to co-exist with the new ACPI usage
> model.
> 
> To use this facility on LPIA platforms, you need to enable the following
> kernel configurations:
>   CONFIG_EARLY_PRINTK_ACPI=y
>   CONFIG_EARLY_PRINTK_INTEL_MID_SPI=y
> Then you need to append the following kernel parameter to the kernel
> command line in the boot loader configuration file:
>   earlyprintk=acpi


.. or earlyprintk=mrst
?
> 
> Signed-off-by: Lv Zheng <lv.zheng@...el.com>
> Reviewed-by: Feng Tang <feng.tang@...el.com>
> ---
>  Documentation/kernel-parameters.txt        |    1 +
>  arch/x86/Kconfig.debug                     |   23 +++
>  arch/x86/include/asm/mrst.h                |    2 +-
>  arch/x86/kernel/early_printk.c             |   12 +-
>  arch/x86/platform/mrst/early_printk_mrst.c |  186 +----------------------
>  drivers/platform/x86/Makefile              |    2 +
>  drivers/platform/x86/early/Makefile        |    5 +
>  drivers/platform/x86/early/intel_mid_spi.c |  220 ++++++++++++++++++++++++++++
>  include/acpi/actbl2.h                      |    1 +
>  include/linux/intel_mid_early.h            |   12 ++
>  10 files changed, 283 insertions(+), 181 deletions(-)
>  create mode 100644 drivers/platform/x86/early/Makefile
>  create mode 100644 drivers/platform/x86/early/intel_mid_spi.c
>  create mode 100644 include/linux/intel_mid_early.h
> 
> diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
> index f656765..003ffd9 100644
> --- a/Documentation/kernel-parameters.txt
> +++ b/Documentation/kernel-parameters.txt
> @@ -762,6 +762,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
>  			earlyprintk=vga
>  			earlyprintk=serial[,ttySn[,baudrate]]
>  			earlyprintk=ttySn[,baudrate]
> +			earlyprintk=mrst
>  			earlyprintk=dbgp[debugController#]
>  			earlyprintk=acpi[debugController#]
>  
> diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug
> index 5778082..4a26e2d 100644
> --- a/arch/x86/Kconfig.debug
> +++ b/arch/x86/Kconfig.debug
> @@ -43,9 +43,32 @@ config EARLY_PRINTK
>  	  with klogd/syslogd or the X server. You should normally N here,
>  	  unless you want to debug such a crash.
>  
> +config EARLY_PRINTK_INTEL_MID_SPI
> +	bool "Early printk for Intel MID SPI UART port"
> +	depends on EARLY_PRINTK
> +	---help---
> +	  Write kernel log output directly into the MID SPI UART debug port.
> +
> +	  Intel MID platforms are using DesignWare SPI UART as its debug
> +	  console.  This option does not introduce actual early console into
> +	  the kernel binary, but is required by a real early console
> +	  implementation (EARLY_PRINTK_INTEL_MID or EARLY_PRINTK_ACPI).
> +	  You should normally N here unless you need to do kernel booting
> +	  development.
> +
>  config EARLY_PRINTK_INTEL_MID
>  	bool "Early printk for Intel MID platform support"
>  	depends on EARLY_PRINTK && X86_INTEL_MID
> +	select EARLY_PRINTK_INTEL_MID_SPI
> +	---help---
> +	  Write kernel log output directly into the MID SPI UART debug port.
> +
> +	  Intel MID platforms are always equipped with SPI debug ports and
> +	  USB OTG debug ports. To enable these debugging facilities, you
> +	  need to pass "earlyprintk=mrst" parameter to the kernel through
> +	  boot loaders.  Please see "Documentation/kernel-parameter.txt" for
> +	  details.  You should normally N here unless you need to do kernel
> +	  booting development.
>  
>  config EARLY_PRINTK_DBGP
>  	bool "Early printk via EHCI debug port"
> diff --git a/arch/x86/include/asm/mrst.h b/arch/x86/include/asm/mrst.h
> index fc18bf3..8ab0655 100644
> --- a/arch/x86/include/asm/mrst.h
> +++ b/arch/x86/include/asm/mrst.h
> @@ -12,6 +12,7 @@
>  #define _ASM_X86_MRST_H
>  
>  #include <linux/sfi.h>
> +#include <linux/intel_mid_early.h>
>  
>  extern int pci_mrst_init(void);
>  extern int __init sfi_parse_mrtc(struct sfi_table_header *table);
> @@ -63,7 +64,6 @@ extern enum mrst_timer_options mrst_timer_options;
>  #define SFI_MTMR_MAX_NUM 8
>  #define SFI_MRTC_MAX	8
>  
> -extern struct console early_mrst_console;
>  extern void mrst_early_console_init(void);
>  
>  extern struct console early_hsu_console;
> diff --git a/arch/x86/kernel/early_printk.c b/arch/x86/kernel/early_printk.c
> index bf5b596..9b5ee96 100644
> --- a/arch/x86/kernel/early_printk.c
> +++ b/arch/x86/kernel/early_printk.c
> @@ -205,6 +205,16 @@ static inline void early_console_register(struct console *con, int keep_early)
>  
>  int __init __acpi_early_console_start(struct acpi_debug_port *info)
>  {
> +#ifdef CONFIG_EARLY_PRINTK_INTEL_MID_SPI
> +	if (info->port_type == ACPI_DBG2_SERIAL_PORT
> +	    && info->port_subtype == ACPI_DBG2_INTEL_MID_SPI
> +	    && info->register_count > 0) {

Is it ever going to be zero?

> +		mid_spi_early_console_init((u32)(info->registers[0].address));
> +		early_console_register(&mid_spi_early_console,
> +				       acpi_early_console_keep(info));
> +	}
> +#endif
> +
>  	return 0;
>  }
>  #endif
> @@ -256,7 +266,7 @@ static int __init setup_early_printk(char *buf)
>  #ifdef CONFIG_EARLY_PRINTK_INTEL_MID
>  		if (!strncmp(buf, "mrst", 4)) {
>  			mrst_early_console_init();
> -			early_console_register(&early_mrst_console, keep);
> +			early_console_register(&mid_spi_early_console, keep);
>  		}
>  
>  		if (!strncmp(buf, "hsu", 3)) {
> diff --git a/arch/x86/platform/mrst/early_printk_mrst.c b/arch/x86/platform/mrst/early_printk_mrst.c
> index 028454f..7afbf18 100644
> --- a/arch/x86/platform/mrst/early_printk_mrst.c
> +++ b/arch/x86/platform/mrst/early_printk_mrst.c
> @@ -29,82 +29,8 @@
>  #include <asm/pgtable.h>
>  #include <asm/mrst.h>
>  
> -#define MRST_SPI_TIMEOUT		0x200000
>  #define MRST_REGBASE_SPI0		0xff128000
>  #define MRST_REGBASE_SPI1		0xff128400
> -#define MRST_CLK_SPI0_REG		0xff11d86c
> -
> -/* Bit fields in CTRLR0 */
> -#define SPI_DFS_OFFSET			0
> -
> -#define SPI_FRF_OFFSET			4
> -#define SPI_FRF_SPI			0x0
> -#define SPI_FRF_SSP			0x1
> -#define SPI_FRF_MICROWIRE		0x2
> -#define SPI_FRF_RESV			0x3
> -
> -#define SPI_MODE_OFFSET			6
> -#define SPI_SCPH_OFFSET			6
> -#define SPI_SCOL_OFFSET			7
> -#define SPI_TMOD_OFFSET			8
> -#define	SPI_TMOD_TR			0x0		/* xmit & recv */
> -#define SPI_TMOD_TO			0x1		/* xmit only */
> -#define SPI_TMOD_RO			0x2		/* recv only */
> -#define SPI_TMOD_EPROMREAD		0x3		/* eeprom read mode */
> -
> -#define SPI_SLVOE_OFFSET		10
> -#define SPI_SRL_OFFSET			11
> -#define SPI_CFS_OFFSET			12
> -
> -/* Bit fields in SR, 7 bits */
> -#define SR_MASK				0x7f		/* cover 7 bits */
> -#define SR_BUSY				(1 << 0)
> -#define SR_TF_NOT_FULL			(1 << 1)
> -#define SR_TF_EMPT			(1 << 2)
> -#define SR_RF_NOT_EMPT			(1 << 3)
> -#define SR_RF_FULL			(1 << 4)
> -#define SR_TX_ERR			(1 << 5)
> -#define SR_DCOL				(1 << 6)
> -
> -struct dw_spi_reg {
> -	u32	ctrl0;
> -	u32	ctrl1;
> -	u32	ssienr;
> -	u32	mwcr;
> -	u32	ser;
> -	u32	baudr;
> -	u32	txfltr;
> -	u32	rxfltr;
> -	u32	txflr;
> -	u32	rxflr;
> -	u32	sr;
> -	u32	imr;
> -	u32	isr;
> -	u32	risr;
> -	u32	txoicr;
> -	u32	rxoicr;
> -	u32	rxuicr;
> -	u32	msticr;
> -	u32	icr;
> -	u32	dmacr;
> -	u32	dmatdlr;
> -	u32	dmardlr;
> -	u32	idr;
> -	u32	version;
> -
> -	/* Currently operates as 32 bits, though only the low 16 bits matter */
> -	u32	dr;
> -} __packed;
> -
> -#define dw_readl(dw, name)		__raw_readl(&(dw)->name)
> -#define dw_writel(dw, name, val)	__raw_writel((val), &(dw)->name)
> -
> -/* Default use SPI0 register for mrst, we will detect Penwell and use SPI1 */
> -static unsigned long mrst_spi_paddr = MRST_REGBASE_SPI0;
> -
> -static u32 *pclk_spi0;
> -/* Always contains an accessible address, start with 0 */
> -static struct dw_spi_reg *pspi;
>  
>  static struct kmsg_dumper dw_dumper;
>  static int dumper_registered;
> @@ -116,77 +42,21 @@ static void dw_kmsg_dump(struct kmsg_dumper *dumper,
>  	size_t len;
>  
>  	/* When run to this, we'd better re-init the HW */
> -	mrst_early_console_init();
> +	mid_spi_early_console_reset();
>  
>  	while (kmsg_dump_get_line(dumper, true, line, sizeof(line), &len))
> -		early_mrst_console.write(&early_mrst_console, line, len);
> -}
> -
> -/* Set the ratio rate to 115200, 8n1, IRQ disabled */
> -static void max3110_write_config(void)
> -{
> -	u16 config;
> -
> -	config = 0xc001;
> -	dw_writel(pspi, dr, config);
> -}
> -
> -/* Translate char to a eligible word and send to max3110 */
> -static void max3110_write_data(char c)
> -{
> -	u16 data;
> -
> -	data = 0x8000 | c;
> -	dw_writel(pspi, dr, data);
> +		mid_spi_early_console.write(&mid_spi_early_console, line, len);
>  }
>  
>  void mrst_early_console_init(void)
>  {
> -	u32 ctrlr0 = 0;
> -	u32 spi0_cdiv;
> -	u32 freq; /* Freqency info only need be searched once */
> -
> -	/* Base clk is 100 MHz, the actual clk = 100M / (clk_divider + 1) */
> -	pclk_spi0 = (void *)set_fixmap_offset_nocache(FIX_EARLYCON_MEM_BASE,
> -							MRST_CLK_SPI0_REG);
> -	spi0_cdiv = ((*pclk_spi0) & 0xe00) >> 9;
> -	freq = 100000000 / (spi0_cdiv + 1);
> +	/* Default use SPI0 register for mrst */
> +	unsigned long spi_paddr = MRST_REGBASE_SPI0;
>  
> +	/* Detect Penwell and use SPI1 */
>  	if (mrst_identify_cpu() == MRST_CPU_CHIP_PENWELL)
> -		mrst_spi_paddr = MRST_REGBASE_SPI1;
> -
> -	pspi = (void *)set_fixmap_offset_nocache(FIX_EARLYCON_MEM_BASE,
> -						mrst_spi_paddr);
> -
> -	/* Disable SPI controller */
> -	dw_writel(pspi, ssienr, 0);
> -
> -	/* Set control param, 8 bits, transmit only mode */
> -	ctrlr0 = dw_readl(pspi, ctrl0);
> -
> -	ctrlr0 &= 0xfcc0;
> -	ctrlr0 |= 0xf | (SPI_FRF_SPI << SPI_FRF_OFFSET)
> -		      | (SPI_TMOD_TO << SPI_TMOD_OFFSET);
> -	dw_writel(pspi, ctrl0, ctrlr0);
> -
> -	/*
> -	 * Change the spi0 clk to comply with 115200 bps, use 100000 to
> -	 * calculate the clk dividor to make the clock a little slower
> -	 * than real baud rate.
> -	 */
> -	dw_writel(pspi, baudr, freq/100000);
> -
> -	/* Disable all INT for early phase */
> -	dw_writel(pspi, imr, 0x0);
> -
> -	/* Set the cs to spi-uart */
> -	dw_writel(pspi, ser, 0x2);
> -
> -	/* Enable the HW, the last step for HW init */
> -	dw_writel(pspi, ssienr, 0x1);
> -
> -	/* Set the default configuration */
> -	max3110_write_config();
> +		spi_paddr = MRST_REGBASE_SPI1;
> +	mid_spi_early_console_init(spi_paddr);
>  
>  	/* Register the kmsg dumper */
>  	if (!dumper_registered) {
> @@ -196,48 +66,6 @@ void mrst_early_console_init(void)
>  	}
>  }
>  
> -/* Slave select should be called in the read/write function */
> -static void early_mrst_spi_putc(char c)
> -{
> -	unsigned int timeout;
> -	u32 sr;
> -
> -	timeout = MRST_SPI_TIMEOUT;
> -	/* Early putc needs to make sure the TX FIFO is not full */
> -	while (--timeout) {
> -		sr = dw_readl(pspi, sr);
> -		if (!(sr & SR_TF_NOT_FULL))
> -			cpu_relax();
> -		else
> -			break;
> -	}
> -
> -	if (!timeout)
> -		pr_warning("MRST earlycon: timed out\n");
> -	else
> -		max3110_write_data(c);
> -}
> -
> -/* Early SPI only uses polling mode */
> -static void early_mrst_spi_write(struct console *con, const char *str, unsigned n)
> -{
> -	int i;
> -
> -	for (i = 0; i < n && *str; i++) {
> -		if (*str == '\n')
> -			early_mrst_spi_putc('\r');
> -		early_mrst_spi_putc(*str);
> -		str++;
> -	}
> -}
> -
> -struct console early_mrst_console = {
> -	.name =		"earlymrst",
> -	.write =	early_mrst_spi_write,
> -	.flags =	CON_PRINTBUFFER,
> -	.index =	-1,
> -};
> -
>  /*
>   * Following is the early console based on Medfield HSU (High
>   * Speed UART) device.
> diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
> index bf7e4f9..6e4ff46 100644
> --- a/drivers/platform/x86/Makefile
> +++ b/drivers/platform/x86/Makefile
> @@ -50,3 +50,5 @@ obj-$(CONFIG_INTEL_MID_POWER_BUTTON)	+= intel_mid_powerbtn.o
>  obj-$(CONFIG_INTEL_OAKTRAIL)	+= intel_oaktrail.o
>  obj-$(CONFIG_SAMSUNG_Q10)	+= samsung-q10.o
>  obj-$(CONFIG_APPLE_GMUX)	+= apple-gmux.o
> +
> +obj-$(CONFIG_EARLY_PRINTK)	+= early/
> diff --git a/drivers/platform/x86/early/Makefile b/drivers/platform/x86/early/Makefile
> new file mode 100644
> index 0000000..5d9408c
> --- /dev/null
> +++ b/drivers/platform/x86/early/Makefile
> @@ -0,0 +1,5 @@
> +#
> +# Makefile for linux/drivers/platform/x86/early
> +# x86 Platform-Specific Early Printk Support
> +#
> +obj-$(CONFIG_EARLY_PRINTK_INTEL_MID_SPI)	+= intel_mid_spi.o
> diff --git a/drivers/platform/x86/early/intel_mid_spi.c b/drivers/platform/x86/early/intel_mid_spi.c
> new file mode 100644
> index 0000000..fa5a1a2
> --- /dev/null
> +++ b/drivers/platform/x86/early/intel_mid_spi.c
> @@ -0,0 +1,220 @@
> +/*
> + * intel_mid_spi.c - SPI UART early consoles for Intel MID platforms
> + *
> + * Copyright (c) 2008-2012, Intel Corporation
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License
> + * as published by the Free Software Foundation; version 2
> + * of the License.
> + */
> +
> +/*
> + * This file is originally implemented by Feng Tang <feng.tang@...el.com>.
> + * It is moved here to co-exist with CONFIG_EARLY_PRINTK_ACPI.
> + * Any questions you should contact the original author.
> + */
> +
> +#include <linux/serial_reg.h>
> +#include <linux/serial_mfd.h>
> +#include <linux/kernel.h>
> +#include <linux/delay.h>
> +#include <linux/init.h>
> +#include <linux/export.h>
> +#include <linux/io.h>
> +#include <linux/intel_mid_early.h>
> +#include <asm/fixmap.h>
> +
> +#define DW_SPI_TIMEOUT			0x200000
> +#define DW_SPI0_CLK_REG			0xff11d86c
> +
> +/* Bit fields in CTRLR0 */
> +#define SPI_DFS_OFFSET			0
> +
> +#define SPI_FRF_OFFSET			4
> +#define SPI_FRF_SPI			0x0
> +#define SPI_FRF_SSP			0x1
> +#define SPI_FRF_MICROWIRE		0x2
> +#define SPI_FRF_RESV			0x3
> +
> +#define SPI_MODE_OFFSET			6
> +#define SPI_SCPH_OFFSET			6
> +#define SPI_SCOL_OFFSET			7
> +#define SPI_TMOD_OFFSET			8
> +#define	SPI_TMOD_TR			0x0		/* xmit & recv */
> +#define SPI_TMOD_TO			0x1		/* xmit only */
> +#define SPI_TMOD_RO			0x2		/* recv only */
> +#define SPI_TMOD_EPROMREAD		0x3		/* eeprom read mode */
> +
> +#define SPI_SLVOE_OFFSET		10
> +#define SPI_SRL_OFFSET			11
> +#define SPI_CFS_OFFSET			12
> +
> +/* Bit fields in SR, 7 bits */
> +#define SR_MASK				0x7f		/* cover 7 bits */
> +#define SR_BUSY				(1 << 0)
> +#define SR_TF_NOT_FULL			(1 << 1)
> +#define SR_TF_EMPT			(1 << 2)
> +#define SR_RF_NOT_EMPT			(1 << 3)
> +#define SR_RF_FULL			(1 << 4)
> +#define SR_TX_ERR			(1 << 5)
> +#define SR_DCOL				(1 << 6)
> +
> +struct dw_spi_reg {
> +	u32	ctrl0;
> +	u32	ctrl1;
> +	u32	ssienr;
> +	u32	mwcr;
> +	u32	ser;
> +	u32	baudr;
> +	u32	txfltr;
> +	u32	rxfltr;
> +	u32	txflr;
> +	u32	rxflr;
> +	u32	sr;
> +	u32	imr;
> +	u32	isr;
> +	u32	risr;
> +	u32	txoicr;
> +	u32	rxoicr;
> +	u32	rxuicr;
> +	u32	msticr;
> +	u32	icr;
> +	u32	dmacr;
> +	u32	dmatdlr;
> +	u32	dmardlr;
> +	u32	idr;
> +	u32	version;
> +
> +	/* Currently operates as 32 bits, though only the low 16 bits matter */
> +	u32	dr;
> +} __packed;
> +
> +#define dw_readl(dw, name)		__raw_readl(&(dw)->name)
> +#define dw_writel(dw, name, val)	__raw_writel((val), &(dw)->name)
> +
> +static u32 *pclk_spi0;
> +/* Always contains an accessible address, start with 0 */
> +static struct dw_spi_reg *pspi;
> +static int dw_spi_initialized;
> +static u32 dw_spi_regbase;
> +
> +/* Translate char to a eligible word and send to max3110 */
> +static void max3110_write_data(char c)
> +{
> +	u16 data;
> +
> +	data = 0x8000 | c;
> +	dw_writel(pspi, dr, data);
> +}
> +
> +/* Set the ratio rate to 115200, 8n1, IRQ disabled */
> +static void max3110_write_config(void)
> +{
> +	u16 config;
> +
> +	config = 0xc001;
> +	dw_writel(pspi, dr, config);
> +}
> +
> +int mid_spi_early_console_reset(void)
> +{
> +	u32 ctrlr0 = 0;
> +	u32 spi0_cdiv;
> +	u32 freq; /* Freqency info only need be searched once */
> +
> +	/* Base clk is 100 MHz, the actual clk = 100M / (clk_divider + 1) */
> +	pclk_spi0 = (void *)set_fixmap_offset_nocache(FIX_EARLYCON_MEM_BASE,
> +						      DW_SPI0_CLK_REG);
> +	spi0_cdiv = ((*pclk_spi0) & 0xe00) >> 9;
> +	freq = 100000000 / (spi0_cdiv + 1);
> +
> +	pspi = (void *)set_fixmap_offset_nocache(FIX_EARLYCON_MEM_BASE,
> +						 dw_spi_regbase);
> +
> +	/* Disable SPI controller */
> +	dw_writel(pspi, ssienr, 0);
> +
> +	/* Set control param, 8 bits, transmit only mode */
> +	ctrlr0 = dw_readl(pspi, ctrl0);
> +
> +	ctrlr0 &= 0xfcc0;
> +	ctrlr0 |= 0xf | (SPI_FRF_SPI << SPI_FRF_OFFSET)
> +		      | (SPI_TMOD_TO << SPI_TMOD_OFFSET);
> +	dw_writel(pspi, ctrl0, ctrlr0);
> +
> +	/*
> +	 * Change the spi0 clk to comply with 115200 bps, use 100000 to
> +	 * calculate the clk dividor to make the clock a little slower
> +	 * than real baud rate.
> +	 */
> +	dw_writel(pspi, baudr, freq/100000);
> +
> +	/* Disable all INT for early phase */
> +	dw_writel(pspi, imr, 0x0);
> +
> +	/* Set the cs to spi-uart */
> +	dw_writel(pspi, ser, 0x2);
> +
> +	/* Enable the HW, the last step for HW init */
> +	dw_writel(pspi, ssienr, 0x1);
> +
> +	/* Set the default configuration */
> +	max3110_write_config();
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL(mid_spi_early_console_reset);
> +
> +/* Slave select should be called in the read/write function */
> +static void dw_early_spi_putc(char c)
> +{
> +	unsigned int timeout;
> +	u32 sr;
> +
> +	timeout = DW_SPI_TIMEOUT;
> +	/* Early putc needs to make sure the TX FIFO is not full */
> +	while (--timeout) {
> +		sr = dw_readl(pspi, sr);
> +		if (!(sr & SR_TF_NOT_FULL))
> +			cpu_relax();
> +		else
> +			break;
> +	}
> +
> +	if (!timeout)
> +		pr_warn("mid-spi-early: timed out\n");
> +	else
> +		max3110_write_data(c);
> +}
> +
> +/* Early SPI only uses polling mode */
> +static void dw_early_spi_write(struct console *con,
> +			       const char *str, unsigned n)
> +{
> +	int i;
> +
> +	for (i = 0; i < n && *str; i++) {
> +		if (*str == '\n')
> +			dw_early_spi_putc('\r');
> +		dw_early_spi_putc(*str);
> +		str++;
> +	}
> +}
> +
> +struct console mid_spi_early_console = {
> +	.name =		"earlymidspi",
> +	.write =	dw_early_spi_write,
> +	.flags =	CON_PRINTBUFFER,
> +	.index =	-1,
> +};
> +
> +void __init mid_spi_early_console_init(u32 spi_paddr)
> +{
> +	if (dw_spi_initialized)
> +		return;
> +	dw_spi_regbase = spi_paddr;
> +	mid_spi_early_console_reset();
> +	dw_spi_initialized = 1;
> +}
> +
> diff --git a/include/acpi/actbl2.h b/include/acpi/actbl2.h
> index 1b2b356..ffa9d62 100644
> --- a/include/acpi/actbl2.h
> +++ b/include/acpi/actbl2.h
> @@ -341,6 +341,7 @@ struct acpi_dbg2_device {
>  
>  #define ACPI_DBG2_16550_COMPATIBLE  0x0000
>  #define ACPI_DBG2_16550_SUBSET      0x0001
> +#define ACPI_DBG2_INTEL_MID_SPI     0x0002
>  
>  #define ACPI_DBG2_1394_STANDARD     0x0000
>  
> diff --git a/include/linux/intel_mid_early.h b/include/linux/intel_mid_early.h
> new file mode 100644
> index 0000000..edba232
> --- /dev/null
> +++ b/include/linux/intel_mid_early.h
> @@ -0,0 +1,12 @@
> +#ifndef LINUX_INTEL_MID_EARLY_H
> +#define LINUX_INTEL_MID_EARLY_H
> +
> +#include <linux/console.h>
> +
> +extern struct console mid_spi_early_console;
> +
> +extern void mid_spi_early_console_init(u32 spi_paddr);
> +extern int mid_spi_early_console_reset(void);
> +
> +#endif /* LINUX_INTEL_MID_EARLY_H */
> +
> -- 
> 1.7.10
> 
> --
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