* Feng Tang <feng.tang@xxxxxxxxx> wrote:
> Intel Moorestown platform has a spi-uart device(Maxim3110), which
> connects to a Designware spi core controller. This patch will add
> early console function based on it.
>
> As it will be used long before Linux spi subsystem get initialised,
> we simply directly manipulate the spi controller's register to
> acheive the early console func. This is safe as it will be disabled
> when devices subsytem get initialised.
>
> To use it, user need enable CONFIG_X86_MRST_EARLY_PRINTK in kenrel
> config and add "earlyprintk=mrst" in kernel command line.
>
> Signed-off-by: Feng Tang <feng.tang@xxxxxxxxx>
> Cc: x86 maintainers <x86@xxxxxxxxxx>
> Signed-off-by: Alan Cox <alan@xxxxxxxxxxxxxxx>
> ---
> arch/x86/Kconfig.debug | 4 +
> arch/x86/include/asm/mrst.h | 4 +
> arch/x86/kernel/Makefile | 1 +
> arch/x86/kernel/early_printk.c | 5 +
> arch/x86/kernel/mrst_earlyprintk.c | 241 ++++++++++++++++++++++++++++++++++++
> 5 files changed, 255 insertions(+), 0 deletions(-)
> create mode 100644 arch/x86/kernel/mrst_earlyprintk.c
>
> diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug
> index 7508508..9c10cd6 100644
> --- a/arch/x86/Kconfig.debug
> +++ b/arch/x86/Kconfig.debug
> @@ -43,6 +43,10 @@ config EARLY_PRINTK
> with klogd/syslogd or the X server. You should normally N here,
> unless you want to debug such a crash.
>
> +config X86_MRST_EARLY_PRINTK
> + bool "Early printk for MRST platform support"
> + depends on EARLY_PRINTK && X86_MRST
> +
> config EARLY_PRINTK_DBGP
> bool "Early printk via EHCI debug port"
> depends on EARLY_PRINTK && PCI
> diff --git a/arch/x86/include/asm/mrst.h b/arch/x86/include/asm/mrst.h
> index 1635074..4b891b3 100644
> --- a/arch/x86/include/asm/mrst.h
> +++ b/arch/x86/include/asm/mrst.h
> @@ -10,6 +10,9 @@
> */
> #ifndef _ASM_X86_MRST_H
> #define _ASM_X86_MRST_H
> +
> +#include <linux/sfi.h>
> +
> extern int pci_mrst_init(void);
> int __init sfi_parse_mrtc(struct sfi_table_header *table);
>
> @@ -42,4 +45,5 @@ 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;
> #endif /* _ASM_X86_MRST_H */
> diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
> index 0925676..e6dbe95 100644
> --- a/arch/x86/kernel/Makefile
> +++ b/arch/x86/kernel/Makefile
> @@ -83,6 +83,7 @@ obj-$(CONFIG_DOUBLEFAULT) += doublefault_32.o
> obj-$(CONFIG_KGDB) += kgdb.o
> obj-$(CONFIG_VM86) += vm86_32.o
> obj-$(CONFIG_EARLY_PRINTK) += early_printk.o
> +obj-$(CONFIG_X86_MRST_EARLY_PRINTK) += mrst_earlyprintk.o
>
> obj-$(CONFIG_HPET_TIMER) += hpet.o
> obj-$(CONFIG_APB_TIMER) += apb_timer.o
> diff --git a/arch/x86/kernel/early_printk.c b/arch/x86/kernel/early_printk.c
> index fa99bae..435a070 100644
> --- a/arch/x86/kernel/early_printk.c
> +++ b/arch/x86/kernel/early_printk.c
> @@ -14,6 +14,7 @@
> #include <xen/hvc-console.h>
> #include <asm/pci-direct.h>
> #include <asm/fixmap.h>
> +#include <asm/mrst.h>
> #include <asm/pgtable.h>
> #include <linux/usb/ehci_def.h>
>
> @@ -239,6 +240,10 @@ static int __init setup_early_printk(char *buf)
> if (!strncmp(buf, "xen", 3))
> early_console_register(&xenboot_console, keep);
> #endif
> +#ifdef CONFIG_X86_MRST_EARLY_PRINTK
> + if (!strncmp(buf, "mrst", 4))
> + early_console_register(&early_mrst_console, keep);
> +#endif
> buf++;
> }
> return 0;
> diff --git a/arch/x86/kernel/mrst_earlyprintk.c b/arch/x86/kernel/mrst_earlyprintk.c
> new file mode 100644
> index 0000000..7c29025
> --- /dev/null
> +++ b/arch/x86/kernel/mrst_earlyprintk.c
Small nit: please name the new file hierarchically and according to
existing namespace patterns: i.e. arch/x86/kernel/early_printk_mrst.c.
> @@ -0,0 +1,241 @@
> +/*
> + * mrst_earlyprintk.c - spi-uart early printk for Intel Moorestown platform
> + *
> + * Copyright (c) 2009 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.
> + */
> +
> +#include <linux/kmsg_dump.h>
> +#include <linux/console.h>
> +#include <linux/kernel.h>
> +#include <linux/init.h>
> +#include <linux/io.h>
> +
> +#include <asm/fixmap.h>
> +#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
Small nit: please try to use uniform vertical spacing for like-minded
symbols - i.e. move the four MRST_* one tab to the right - so that if
someone looks at the file for the first time sees a tidy picture of
constants, without extra visual noise.
> +
> +#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;
> + u32 dr; /* Currently oper as 32 bits,
> + though only low 16 bits matters */
please use the customary (multi-line) comment style:
/*
* Comment .....
* ...... goes here.
*/
specified in Documentation/CodingStyle. (or use an overlong comment line
and ignore checkpatch)
Also, the sentence should probably read:
/* Currently operates as 32 bits, though only the low 16 bits matter */
> +} __packed;
> +
> +#define dw_readl(dw, name) \
> + __raw_readl(&dw->name)
> +#define dw_writel(dw, name, val) \
> + __raw_writel((val), &dw->name)
'dw' needs to be macro-side-effect protected as well, not just 'val'.
Also, these definitions do not need to be multi-line. This looks much
tidier:
#define dw_readl(dw, name) __raw_readl(&(dw)->name)
#define dw_writel(dw, name, val) __raw_writel((val), &(dw)->name)
( for extra bonus see that the vertical spacing lines up with the
constant section higher in the file. )
> +
> +/* 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 accessable address, start with 0 */
> +static struct dw_spi_reg *pspi;
> +static int mrst_spi_init_done;
> +
> +static struct kmsg_dumper dw_dumper;
> +static int dumper_registered;
> +
> +static void dw_kmsg_dump(struct kmsg_dumper *dumper,
> + enum kmsg_dump_reason reason,
> + const char *s1, unsigned long l1,
> + const char *s2, unsigned long l2)
> +{
> + int i;
> +
> + /* When run to this, we'd better re-init the HW */
> + mrst_spi_init_done = 0;
The mrst_spi_init_done flaggery and its interaction with implicit
initialization in the write() method is really ugly and non-obvious.
Please add an explicit 'first initialization' call in the MRST bootup
code (or somewhere in the x86 bootup code), and then explicitly call
early_mrst_spi_init() here in the dumper.
This allows the elimination of mrst_spi_init_done.
> +
> + for (i = 0; i < l1; i++)
> + early_mrst_console.write(&early_mrst_console, s1 + i, 1);
> + for (i = 0; i < l2; i++)
> + early_mrst_console.write(&early_mrst_console, s2 + i, 1);
> +}
> +
> +static void early_mrst_spi_init(void)
> +{
> + u32 ctrlr0 = 0;
> + u32 spi0_cdiv;
> + static u32 freq; /* freq info only need be searched once */
Very small nit: please use consistent capitalization in comments. This
comment should be capitalized - as most other comments are in the file.
> +
> + if (!freq) {
> + set_fixmap_nocache(FIX_EARLYCON_MEM_BASE, MRST_CLK_SPI0_REG);
> + pclk_spi0 = (void *)(__fix_to_virt(FIX_EARLYCON_MEM_BASE) +
> + (MRST_CLK_SPI0_REG & (PAGE_SIZE - 1)));
> +
> + spi0_cdiv = ((*pclk_spi0) & 0xe00) >> 9;
> + freq = 100000000 / (spi0_cdiv + 1);
> + }
> +
> + if (mrst_identify_cpu() == MRST_CPU_CHIP_PENWELL)
> + mrst_spi_paddr = MRST_REGBASE_SPI1;
> +
> + set_fixmap_nocache(FIX_EARLYCON_MEM_BASE, mrst_spi_paddr);
> + pspi = (void *)(__fix_to_virt(FIX_EARLYCON_MEM_BASE) +
> + (mrst_spi_paddr & (PAGE_SIZE - 1)));
> +
> + /* 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 as dividor to make the clock a little
> + * slower than baud rate */
Comment style.
> + 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);
> +
> + mrst_spi_init_done = 1;
> +
> + /* Register the kmsg dumper */
> + if (!dumper_registered) {
> + dw_dumper.dump = dw_kmsg_dump;
> + kmsg_dump_register(&dw_dumper);
> + dumper_registered = 1;
> + }
> +}
> +
> +/* Set the ratio rate, INT */
> +static void max3110_write_config(void)
> +{
> + u16 config;
> +
> + /* 115200, TM not set, no parity, 8bit word */
> + config = 0xc001;
> + dw_writel(pspi, dr, config);
> +}
> +
> +/* Translate char to a eligibal word and send to max3110 */
eligible?
> +static void max3110_write_data(char c)
> +{
> + u16 data;
> +
> + data = 0x8000 | c;
> + dw_writel(pspi, dr, data);
> +}
> +
> +/* 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 need make sure the TX FIFO is not full*/
Comments end with ' */', not with '*/', plus the sentence should
probably read:
/* 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("SPI: waiting timeout\n");
"SPI: timed out\n"
or:
"SPI: waiting timed out\n"
> + else
> + max3110_write_data(c);
> +}
> +
> +/* Early SPI only use polling mode */
s/use/uses
> +static void early_mrst_spi_write(struct console *con, const char *str, unsigned n)
> +{
> + int i;
> +
> + if (unlikely(!mrst_spi_init_done)) {
> + early_mrst_spi_init();
> + max3110_write_config();
> + }
Shouldnt the call to max3110_write_config() be moved into
early_mrst_spi_init()?
> +
> + 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,
> +};
Thanks,
Ingo
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