[PATCH 1/5] mrst_earlyprintk: add a kmsg_dumper to dump the printk buffer when panic

[PATCH 1/5] mrst_earlyprintk: add a kmsg_dumper to dump the printk buffer when panic

[Alan Cox]

From: Feng Tang <feng.tang@intel.com>

As normal max3110 console can't work during panic case, add a helper
function which make debug easier

Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
---

 arch/x86/Kconfig                   |   18 ++
 arch/x86/Kconfig.debug             |    4 +
 arch/x86/include/asm/mrst.h        |    5 +
 arch/x86/kernel/Makefile           |    1 
 arch/x86/kernel/early_printk.c     |    5 +
 arch/x86/kernel/mrst_earlyprintk.c |  283 ++++++++++++++++++++++++++++++++++++
 6 files changed, 311 insertions(+), 5 deletions(-)
 create mode 100644 arch/x86/kernel/mrst_earlyprintk.c


diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 162d1aa..97d3016 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -420,6 +420,14 @@ config X86_MRST
 	  nor standard legacy replacement devices/features. e.g. Moorestown does
 	  not contain i8259, i8254, HPET, legacy BIOS, most of the io ports.
 
+config MRST_SPI_UART_BOOT_MSG
+	def_bool y
+	prompt "Moorestown SPI UART boot message"
+	depends on (X86_MRST && X86_32)
+	help
+	  Enable this to see boot message during protected mode boot phase, such as
+	  kernel decompression, BAUD rate is set at 115200 8n1
+
 config X86_RDC321X
 	bool "RDC R-321x SoC"
 	depends on X86_32
@@ -630,11 +638,11 @@ config APB_TIMER
        def_bool y if MRST
        prompt "Langwell APB Timer Support" if X86_MRST
        help
-         APB timer is the replacement for 8254, HPET on X86 MID platforms.
-         The APBT provides a stable time base on SMP
-         systems, unlike the TSC, but it is more expensive to access,
-         as it is off-chip. APB timers are always running regardless of CPU
-         C states, they are used as per CPU clockevent device when possible.
+		APB timer is the replacement for 8254, HPET on X86 MID platforms.
+		The APBT provides a stable time base on SMP
+		systems, unlike the TSC, but it is more expensive to access,
+		as it is off-chip. APB timers are always running regardless of CPU
+		C states, they are used as per CPU clockevent device when possible.
 
 # Mark as embedded because too many people got it wrong.
 # The code disables itself when not needed.
diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug
index 7f15308..3e104d1 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..704d2fd 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 +45,6 @@ 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_printk(const char *fmt, ...);
 #endif /* _ASM_X86_MRST_H */
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 11a9925..e0a8357 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -84,6 +84,7 @@ 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..4aff765
--- /dev/null
+++ b/arch/x86/kernel/mrst_earlyprintk.c
@@ -0,0 +1,283 @@
+/*
+ * 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
+
+#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 */
+} __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;
+
+/* Always contains a accessable address, start with 0 */
+static u32 *pclk_spi0;
+static struct dw_spi_reg *pspi;
+static int mrst_spi_inited;
+static spinlock_t dw_lock;
+static int real_pgt_is_up;
+
+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_inited = 0;
+
+	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);
+}
+
+/*
+ * One trick for the early printk is that it could be called
+ * before and after the real page table is enabled for kernel,
+ * so the PHY IO registers should be mapped twice. And a flag
+ * "real_pgt_is_up" is used as an indicator
+ */
+static void early_mrst_spi_init(void)
+{
+	u32 ctrlr0 = 0;
+	u32 spi0_cdiv;
+	static u32 freq; /* freq info only need be searched once */
+
+	if (pspi && mrst_spi_inited)
+		return;
+
+	spin_lock_init(&dw_lock);
+
+	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 */
+	dw_writel(pspi, baudr, freq/100000);
+
+	/* disable all INT for early phase */
+	dw_writel(pspi, imr, 0x0);
+
+	/* set the cs to max3110 */
+	dw_writel(pspi, ser, 0x2);
+
+	/* enable the HW, the last step for HW init */
+	dw_writel(pspi, ssienr, 0x1);
+
+	mrst_spi_inited = 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);
+}
+
+/* transfer char to a eligibal word and send to max3110 */
+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 int 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*/
+	while (timeout--) {
+		sr = dw_readl(pspi, sr);
+		if (!(sr & SR_TF_NOT_FULL))
+			cpu_relax();
+		else
+			break;
+	}
+
+	if (timeout == 0xffffffff) {
+		printk(KERN_INFO "SPI: waiting timeout\n");
+		return -1;
+	}
+
+	max3110_write_data(c);
+	return 0;
+}
+
+/* early SPI only use polling mode */
+static void early_mrst_spi_write(struct console *con,
+				const char *str, unsigned n)
+{
+	int  i;
+	unsigned long flags;
+
+	if ((read_cr3() == __pa(swapper_pg_dir)) && !real_pgt_is_up) {
+		mrst_spi_inited = 0;
+		real_pgt_is_up = 1;
+	}
+
+	if (unlikely(!mrst_spi_inited)) {
+		early_mrst_spi_init();
+		max3110_write_config();
+	}
+
+	spin_lock_irqsave(&dw_lock, flags);
+	for (i = 0; i < n && *str; i++) {
+		if (*str == '\n')
+			early_mrst_spi_putc('\r');
+		early_mrst_spi_putc(*str);
+
+		str++;
+	}
+	spin_unlock_irqrestore(&dw_lock, flags);
+}
+
+struct console early_mrst_console = {
+	.name =		"earlymrst",
+	.write =	early_mrst_spi_write,
+	.flags =	CON_PRINTBUFFER,
+	.index =	-1,
+};
+
+/* a debug function */
+void mrst_early_printk(const char *fmt, ...)
+{
+	char buf[512];
+	int n;
+	va_list ap;
+
+	va_start(ap, fmt);
+	n = vscnprintf(buf, 512, fmt, ap);
+	va_end(ap);
+
+	early_mrst_console.write(&early_mrst_console, buf, n);
+}

[PATCH 2/5] hsu, earlyprintk: add early printk for hsu_port2 console

[Alan Cox]

From: Feng Tang <feng.tang@intel.com>

To enable early printk of HSU console, simply set "earlyprint=hsu" in
kernel command line.

Currently we put the code in the mrst_earlyprintk.c and it need enable
CONFIG_X86_MRST_EARLY_PRINTK config option

Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
---

 arch/x86/include/asm/mrst.h        |    1 
 arch/x86/kernel/early_printk.c     |    3 +
 arch/x86/kernel/mrst_earlyprintk.c |  128 ++++++++++++++++++++++++++++++++++++
 3 files changed, 132 insertions(+), 0 deletions(-)


diff --git a/arch/x86/include/asm/mrst.h b/arch/x86/include/asm/mrst.h
index 704d2fd..b6531da 100644
--- a/arch/x86/include/asm/mrst.h
+++ b/arch/x86/include/asm/mrst.h
@@ -46,5 +46,6 @@ extern enum mrst_timer_options mrst_timer_options;
 #define SFI_MRTC_MAX	8
 
 extern struct console early_mrst_console;
+extern struct console early_hsu_console;
 extern void mrst_early_printk(const char *fmt, ...);
 #endif /* _ASM_X86_MRST_H */
diff --git a/arch/x86/kernel/early_printk.c b/arch/x86/kernel/early_printk.c
index 435a070..fd095e7 100644
--- a/arch/x86/kernel/early_printk.c
+++ b/arch/x86/kernel/early_printk.c
@@ -243,6 +243,9 @@ static int __init setup_early_printk(char *buf)
 #ifdef CONFIG_X86_MRST_EARLY_PRINTK
 		if (!strncmp(buf, "mrst", 4))
 			early_console_register(&early_mrst_console, keep);
+
+		if (!strncmp(buf, "hsu", 3))
+			early_console_register(&early_hsu_console, keep);
 #endif
 		buf++;
 	}
diff --git a/arch/x86/kernel/mrst_earlyprintk.c b/arch/x86/kernel/mrst_earlyprintk.c
index 4aff765..1fb1305 100644
--- a/arch/x86/kernel/mrst_earlyprintk.c
+++ b/arch/x86/kernel/mrst_earlyprintk.c
@@ -9,9 +9,12 @@
  * of the License.
  */
 
+#include <linux/serial_reg.h>
+#include <linux/serial_mfd.h>
 #include <linux/kmsg_dump.h>
 #include <linux/console.h>
 #include <linux/kernel.h>
+#include <linux/delay.h>
 #include <linux/init.h>
 #include <linux/io.h>
 
@@ -281,3 +284,128 @@ void mrst_early_printk(const char *fmt, ...)
 
 	early_mrst_console.write(&early_mrst_console, buf, n);
 }
+
+
+/* Will use HSU port2 for early console */
+
+/*
+ * Note:
+ * 1. still need GPIO workaround for UART2
+ *
+ */
+static spinlock_t hsu_lock;
+static int hsu_inited;
+static void __iomem *phsu;
+#define HSU_PORT2_PADDR		0xffa28180
+#define MFD_GPIO_HSU_REG	0xff12c064
+
+static void early_hsu_init(void)
+{
+	u8 lcr;
+
+	if (phsu && hsu_inited)
+		return;
+
+	spin_lock_init(&hsu_lock);
+
+	/* GPIO workaround */
+	set_fixmap_nocache(FIX_EARLYCON_MEM_BASE, MFD_GPIO_HSU_REG);
+	phsu = (void *)(__fix_to_virt(FIX_EARLYCON_MEM_BASE) +
+			(MFD_GPIO_HSU_REG & (PAGE_SIZE - 1)));
+
+	*((u32 *)phsu) = 0x55465;
+
+	set_fixmap_nocache(FIX_EARLYCON_MEM_BASE, HSU_PORT2_PADDR);
+	phsu = (void *)(__fix_to_virt(FIX_EARLYCON_MEM_BASE) +
+			(HSU_PORT2_PADDR & (PAGE_SIZE - 1)));
+
+	writeb(0x0, phsu + UART_FCR);
+
+	/* set to default 115200 */
+	lcr = readb(phsu + UART_LCR);
+	writeb((0x80 | lcr), phsu + UART_LCR);
+	writeb(0x18, phsu + UART_DLL);
+	writeb(lcr,  phsu + UART_LCR);
+	writel(0x3600, phsu + UART_MUL*4);
+
+	writeb(0x8, phsu + UART_MCR);
+	writeb(0x7, phsu + UART_FCR);
+	writeb(0x3, phsu + UART_LCR);
+
+	/* clear IRQ status */
+	readb(phsu + UART_LSR);
+	readb(phsu + UART_RX);
+	readb(phsu + UART_IIR);
+	readb(phsu + UART_MSR);
+
+
+
+	writeb(0x7, phsu + UART_FCR);
+
+	hsu_inited = 1;
+}
+
+#define BOTH_EMPTY (UART_LSR_TEMT | UART_LSR_THRE)
+static void early_hsu_putc(char ch)
+{
+	unsigned int timeout = 10000; /* 10ms*/
+	u8 status;
+
+	while (timeout--) {
+		status = readb(phsu + UART_LSR);
+		if (status & BOTH_EMPTY)
+			break;
+
+		udelay(1);
+	}
+
+	if (timeout == 0xffffffff)
+		return;
+
+	writeb(ch, phsu + UART_TX);
+}
+
+static void early_hsu_write(struct console *con,
+			const char *str, unsigned n)
+{
+	int  i;
+	unsigned long flags;
+
+	/*
+	printk("%s(): enter\n\n", __func__);
+	*/
+
+	if (unlikely(!hsu_inited))
+		early_hsu_init();
+
+	spin_lock_irqsave(&hsu_lock, flags);
+	for (i = 0; i < n && *str; i++) {
+		if (*str == '\n')
+			early_hsu_putc('\r');
+		early_hsu_putc(*str);
+
+		str++;
+	}
+	spin_unlock_irqrestore(&hsu_lock, flags);
+}
+
+
+struct console early_hsu_console = {
+	.name =		"earlyhsu",
+	.write =	early_hsu_write,
+	.flags =	CON_PRINTBUFFER,
+	.index =	-1,
+};
+
+void hsu_early_printk(const char *fmt, ...)
+{
+	char buf[512];
+	int n;
+	va_list ap;
+
+	va_start(ap, fmt);
+	n = vscnprintf(buf, 512, fmt, ap);
+	va_end(ap);
+
+	early_hsu_console.write(&early_mrst_console, buf, n);
+}

[PATCH 3/5] hsu, earlyprintk: remove the GPIO work around

[Alan Cox]

From: Feng Tang <feng.tang@intel.com>

Latest firmware will correctly configure the GPIO lines used by
hsu console, so remove that workaround.

Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
---

 arch/x86/kernel/mrst_earlyprintk.c |   20 --------------------
 1 files changed, 0 insertions(+), 20 deletions(-)


diff --git a/arch/x86/kernel/mrst_earlyprintk.c b/arch/x86/kernel/mrst_earlyprintk.c
index 1fb1305..d1a49a7 100644
--- a/arch/x86/kernel/mrst_earlyprintk.c
+++ b/arch/x86/kernel/mrst_earlyprintk.c
@@ -287,17 +287,10 @@ void mrst_early_printk(const char *fmt, ...)
 
 
 /* Will use HSU port2 for early console */
-
-/*
- * Note:
- * 1. still need GPIO workaround for UART2
- *
- */
 static spinlock_t hsu_lock;
 static int hsu_inited;
 static void __iomem *phsu;
 #define HSU_PORT2_PADDR		0xffa28180
-#define MFD_GPIO_HSU_REG	0xff12c064
 
 static void early_hsu_init(void)
 {
@@ -308,13 +301,6 @@ static void early_hsu_init(void)
 
 	spin_lock_init(&hsu_lock);
 
-	/* GPIO workaround */
-	set_fixmap_nocache(FIX_EARLYCON_MEM_BASE, MFD_GPIO_HSU_REG);
-	phsu = (void *)(__fix_to_virt(FIX_EARLYCON_MEM_BASE) +
-			(MFD_GPIO_HSU_REG & (PAGE_SIZE - 1)));
-
-	*((u32 *)phsu) = 0x55465;
-
 	set_fixmap_nocache(FIX_EARLYCON_MEM_BASE, HSU_PORT2_PADDR);
 	phsu = (void *)(__fix_to_virt(FIX_EARLYCON_MEM_BASE) +
 			(HSU_PORT2_PADDR & (PAGE_SIZE - 1)));
@@ -338,8 +324,6 @@ static void early_hsu_init(void)
 	readb(phsu + UART_IIR);
 	readb(phsu + UART_MSR);
 
-
-
 	writeb(0x7, phsu + UART_FCR);
 
 	hsu_inited = 1;
@@ -371,10 +355,6 @@ static void early_hsu_write(struct console *con,
 	int  i;
 	unsigned long flags;
 
-	/*
-	printk("%s(): enter\n\n", __func__);
-	*/
-
 	if (unlikely(!hsu_inited))
 		early_hsu_init();
 

[PATCH 4/5] serial: mrst_max3110: some code cleanup

[Alan Cox]

From: Feng Tang <feng.tang@intel.com>

The cleanup for mrst_max3110 includes:
* remove unneeded head files
* make the spi_transfer dma safe, so that driver is more portable
* add more check for error return value
* use mutex_trylock for read thread

Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
---

 drivers/serial/mrst_max3110.c |  323 +++++++++++++++++++++++++----------------
 drivers/serial/mrst_max3110.h |    1 
 2 files changed, 199 insertions(+), 125 deletions(-)


diff --git a/drivers/serial/mrst_max3110.c b/drivers/serial/mrst_max3110.c
index f6ad1ec..880dce3 100644
--- a/drivers/serial/mrst_max3110.c
+++ b/drivers/serial/mrst_max3110.c
@@ -1,7 +1,7 @@
 /*
- *  max3110.c - spi uart protocol driver for Maxim 3110 on Moorestown
+ *  mrst_max3110.c - spi uart protocol driver for Maxim 3110
  *
- *  Copyright (C) Intel 2008 Feng Tang <feng.tang@intel.com>
+ * Copyright (c) 2010, Intel Corporation.
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms and conditions of the GNU General Public License,
@@ -31,18 +31,13 @@
 #include <linux/ioport.h>
 #include <linux/init.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/serial_reg.h>
 
 #include <linux/kthread.h>
-#include <linux/delay.h>
-#include <asm/atomic.h>
 #include <linux/spi/spi.h>
-#include <linux/spi/dw_spi.h>
 
 #include "mrst_max3110.h"
 
@@ -55,7 +50,7 @@
 struct uart_max3110 {
 	struct uart_port port;
 	struct spi_device *spi;
-	char *name;
+	char name[24];
 
 	wait_queue_head_t wq;
 	struct task_struct *main_thread;
@@ -66,35 +61,30 @@ struct uart_max3110 {
 	u16 cur_conf;
 	u8 clock;
 	u8 parity, word_7bits;
+	u16 irq;
 
 	unsigned long uart_flags;
 
 	/* console related */
 	struct circ_buf con_xmit;
-
-	/* irq related */
-	u16 irq;
 };
 
 /* global data structure, may need be removed */
-struct uart_max3110 *pmax;
-static inline void receive_char(struct uart_max3110 *max, u8 ch);
+static struct uart_max3110 *pmax;
+
 static void receive_chars(struct uart_max3110 *max,
 				unsigned char *str, int len);
-static int max3110_read_multi(struct uart_max3110 *max, int len, u8 *buf);
-static void max3110_console_receive(struct uart_max3110 *max);
+static int max3110_read_multi(struct uart_max3110 *max, u8 *buf);
+static void max3110_con_receive(struct uart_max3110 *max);
 
-int max3110_write_then_read(struct uart_max3110 *max,
-		const u8 *txbuf, u8 *rxbuf, unsigned len, int always_fast)
+static int max3110_write_then_read(struct uart_max3110 *max,
+		const void *txbuf, void *rxbuf, unsigned len, int always_fast)
 {
 	struct spi_device *spi = max->spi;
 	struct spi_message	message;
 	struct spi_transfer	x;
 	int ret;
 
-	if (!txbuf || !rxbuf)
-		return -EINVAL;
-
 	spi_message_init(&message);
 	memset(&x, 0, sizeof x);
 	x.len = len;
@@ -103,7 +93,7 @@ int max3110_write_then_read(struct uart_max3110 *max,
 	spi_message_add_tail(&x, &message);
 
 	if (always_fast)
-		x.speed_hz = 3125000;
+		x.speed_hz = spi->max_speed_hz;
 	else if (max->baud)
 		x.speed_hz = max->baud;
 
@@ -112,58 +102,80 @@ int max3110_write_then_read(struct uart_max3110 *max,
 	return ret;
 }
 
-/* Write a u16 to the device, and return one u16 read back */
-int max3110_out(struct uart_max3110 *max, const u16 out)
+/* Write a 16b word to the device */
+static int max3110_out(struct uart_max3110 *max, const u16 out)
 {
-	u16 tmp;
+	void *buf;
+	u16 *obuf, *ibuf;
+	u8  ch;
 	int ret;
 
-	ret = max3110_write_then_read(max, (u8 *)&out, (u8 *)&tmp, 2, 1);
-	if (ret)
-		return ret;
+	buf = kzalloc(8, GFP_KERNEL | GFP_DMA);
+	if (!buf)
+		return -ENOMEM;
+
+	obuf = buf;
+	ibuf = buf + 4;
+	*obuf = out;
+	ret = max3110_write_then_read(max, obuf, ibuf, 2, 1);
+	if (ret) {
+		pr_warning(PR_FMT "%s(): get err msg %d when sending 0x%x\n",
+				__func__, ret, out);
+		goto exit;
+	}
 
 	/* If some valid data is read back */
-	if (tmp & MAX3110_READ_DATA_AVAILABLE)
-		receive_char(max, (tmp & 0xff));
+	if (*ibuf & MAX3110_READ_DATA_AVAILABLE) {
+		ch = *ibuf & 0xff;
+		receive_chars(max, &ch, 1);
+	}
 
+exit:
+	kfree(buf);
 	return ret;
 }
 
-#define MAX_READ_LEN	20
 /*
  * This is usually used to read data from SPIC RX FIFO, which doesn't
- * need any delay like flushing character out. It returns how many
- * valide bytes are read back
+ * need any delay like flushing character out.
+ *
+ * Return how many valide bytes are read back
  */
-static int max3110_read_multi(struct uart_max3110 *max, int len, u8 *buf)
+static int max3110_read_multi(struct uart_max3110 *max, u8 *rxbuf)
 {
-	u16 out[MAX_READ_LEN], in[MAX_READ_LEN];
-	u8 *pbuf, valid_str[MAX_READ_LEN];
-	int i, j, bytelen;
+	void *buf;
+	u16 *obuf, *ibuf;
+	u8 *pbuf, valid_str[M3110_RX_FIFO_DEPTH];
+	int i, j, blen;
 
-	if (len > MAX_READ_LEN) {
-		pr_err(PR_FMT "read len %d is too large\n", len);
+	blen = M3110_RX_FIFO_DEPTH * sizeof(u16);
+	buf = kzalloc(blen * 2, GFP_KERNEL | GFP_DMA);
+	if (!buf) {
+		pr_warning(PR_FMT "%s(): fail to alloc dma buffer\n", __func__);
 		return 0;
 	}
 
-	bytelen = len * 2;
-	memset(out, 0, bytelen);
-	memset(in, 0, bytelen);
+	/* tx/rx always have the same length */
+	obuf = buf;
+	ibuf = buf + blen;
 
-	if (max3110_write_then_read(max, (u8 *)out, (u8 *)in, bytelen, 1))
+	if (max3110_write_then_read(max, obuf, ibuf, blen, 1)) {
+		kfree(buf);
 		return 0;
+	}
 
-	/* If caller don't provide a buffer, then handle received char */
-	pbuf = buf ? buf : valid_str;
+	/* If caller doesn't provide a buffer, then handle received char */
+	pbuf = rxbuf ? rxbuf : valid_str;
 
-	for (i = 0, j = 0; i < len; i++) {
-		if (in[i] & MAX3110_READ_DATA_AVAILABLE)
-			pbuf[j++] = (u8)(in[i] & 0xff);
+	for (i = 0, j = 0; i < M3110_RX_FIFO_DEPTH; i++) {
+		if (ibuf[i] & MAX3110_READ_DATA_AVAILABLE)
+			pbuf[j++] = ibuf[i] & 0xff;
 	}
 
 	if (j && (pbuf == valid_str))
 		receive_chars(max, valid_str, j);
 
+	kfree(buf);
 	return j;
 }
 
@@ -177,10 +189,6 @@ static void serial_m3110_con_putchar(struct uart_port *port, int ch)
 		xmit->buf[xmit->head] = (char)ch;
 		xmit->head = (xmit->head + 1) & (PAGE_SIZE - 1);
 	}
-
-
-	if (!test_and_set_bit(CON_TX_NEEDED, &max->uart_flags))
-		wake_up_process(max->main_thread);
 }
 
 /*
@@ -196,6 +204,9 @@ static void serial_m3110_con_write(struct console *co,
 		return;
 
 	uart_console_write(&pmax->port, s, count, serial_m3110_con_putchar);
+
+	if (!test_and_set_bit(CON_TX_NEEDED, &pmax->uart_flags))
+		wake_up_process(pmax->main_thread);
 }
 
 static int __init
@@ -209,6 +220,9 @@ serial_m3110_con_setup(struct console *co, char *options)
 
 	pr_info(PR_FMT "setting up console\n");
 
+	if (co->index == -1)
+		co->index = 0;
+
 	if (!max) {
 		pr_err(PR_FMT "pmax is NULL, return");
 		return -ENODEV;
@@ -239,8 +253,6 @@ static struct console serial_m3110_console = {
 	.data		= &serial_m3110_reg,
 };
 
-#define MRST_CONSOLE	(&serial_m3110_console)
-
 static unsigned int serial_m3110_tx_empty(struct uart_port *port)
 {
 	return 1;
@@ -258,32 +270,44 @@ static void serial_m3110_stop_rx(struct uart_port *port)
 }
 
 #define WORDS_PER_XFER	128
-static inline void send_circ_buf(struct uart_max3110 *max,
+static void send_circ_buf(struct uart_max3110 *max,
 				struct circ_buf *xmit)
 {
-	int len, left = 0;
-	u16 obuf[WORDS_PER_XFER], ibuf[WORDS_PER_XFER];
+	void *buf;
+	u16 *obuf, *ibuf;
 	u8 valid_str[WORDS_PER_XFER];
-	int i, j;
+	int i, j, len, blen, dma_size, left, ret = 0;
+
+
+	dma_size = WORDS_PER_XFER * sizeof(u16) * 2;
+	buf = kzalloc(dma_size, GFP_KERNEL | GFP_DMA);
+	if (!buf)
+		return;
+	obuf = buf;
+	ibuf = buf + dma_size/2;
 
 	while (!uart_circ_empty(xmit)) {
 		left = uart_circ_chars_pending(xmit);
 		while (left) {
-			len = (left >= WORDS_PER_XFER) ? WORDS_PER_XFER : left;
+			len = min(left, WORDS_PER_XFER);
+			blen = len * sizeof(u16);
+			memset(ibuf, 0, blen);
 
-			memset(obuf, 0, len * 2);
-			memset(ibuf, 0, len * 2);
 			for (i = 0; i < len; i++) {
 				obuf[i] = (u8)xmit->buf[xmit->tail] | WD_TAG;
 				xmit->tail = (xmit->tail + 1) &
 						(UART_XMIT_SIZE - 1);
 			}
-			max3110_write_then_read(max, (u8 *)obuf,
-						(u8 *)ibuf, len * 2, 0);
+
+			/* Fail to send msg to console is not very critical */
+			ret = max3110_write_then_read(max, obuf, ibuf, blen, 0);
+			if (ret)
+				pr_warning(PR_FMT "%s(): get err msg %d\n",
+						__func__, ret);
 
 			for (i = 0, j = 0; i < len; i++) {
 				if (ibuf[i] & MAX3110_READ_DATA_AVAILABLE)
-					valid_str[j++] = (u8)(ibuf[i] & 0xff);
+					valid_str[j++] = ibuf[i] & 0xff;
 			}
 
 			if (j)
@@ -293,6 +317,8 @@ static inline void send_circ_buf(struct uart_max3110 *max,
 			left -= len;
 		}
 	}
+
+	kfree(buf);
 }
 
 static void transmit_char(struct uart_max3110 *max)
@@ -312,8 +338,10 @@ static void transmit_char(struct uart_max3110 *max)
 		serial_m3110_stop_tx(port);
 }
 
-/* This will be called by uart_write() and tty_write, can't
- * go to sleep */
+/*
+ * This will be called by uart_write() and tty_write, can't
+ * go to sleep
+ */
 static void serial_m3110_start_tx(struct uart_port *port)
 {
 	struct uart_max3110 *max =
@@ -335,7 +363,7 @@ static void receive_chars(struct uart_max3110 *max, unsigned char *str, int len)
 
 	tty = port->state->port.tty;
 	if (!tty)
-		return;	/* receive some char before the tty is opened */
+		return;
 
 	while (len) {
 		usable = tty_buffer_request_room(tty, len);
@@ -343,32 +371,37 @@ static void receive_chars(struct uart_max3110 *max, unsigned char *str, int len)
 			tty_insert_flip_string(tty, str, usable);
 			str += usable;
 			port->icount.rx += usable;
-			tty_flip_buffer_push(tty);
 		}
 		len -= usable;
 	}
+	tty_flip_buffer_push(tty);
 }
 
-static inline void receive_char(struct uart_max3110 *max, u8 ch)
-{
-	receive_chars(max, &ch, 1);
-}
-
-static void max3110_console_receive(struct uart_max3110 *max)
+/*
+ * This routine will be used in read_thread or RX IRQ handling,
+ * it will first do one round buffer read(8 words), if there is some
+ * valid RX data, will try to read 5 more rounds till all data
+ * is read out.
+ *
+ * Use stack space as data buffer to save some system load, and chose
+ * 504 Btyes as a threadhold to do a bulk push to upper tty layer when
+ * receiving bulk data, a much bigger buffer may cause stack overflow
+ */
+static void max3110_con_receive(struct uart_max3110 *max)
 {
 	int loop = 1, num, total = 0;
 	u8 recv_buf[512], *pbuf;
 
 	pbuf = recv_buf;
 	do {
-		num = max3110_read_multi(max, 8, pbuf);
+		num = max3110_read_multi(max, pbuf);
 
 		if (num) {
-			loop = 10;
+			loop = 5;
 			pbuf += num;
 			total += num;
 
-			if (total >= 500) {
+			if (total >= 504) {
 				receive_chars(max, recv_buf, total);
 				pbuf = recv_buf;
 				total = 0;
@@ -396,7 +429,7 @@ static int max3110_main_thread(void *_max)
 		mutex_lock(&max->thread_mutex);
 
 		if (test_and_clear_bit(BIT_IRQ_PENDING, &max->uart_flags))
-			max3110_console_receive(max);
+			max3110_con_receive(max);
 
 		/* first handle console output */
 		if (test_and_clear_bit(CON_TX_NEEDED, &max->uart_flags))
@@ -433,9 +466,14 @@ static int max3110_read_thread(void *_max)
 
 	pr_info(PR_FMT "start read thread\n");
 	do {
-		mutex_lock(&max->thread_mutex);
-		max3110_console_receive(max);
-		mutex_unlock(&max->thread_mutex);
+		/*
+		 * If can't acquire the mutex, it means the main thread
+		 * is running which will also perform the rx job
+		 */
+		if (mutex_trylock(&max->thread_mutex)) {
+			max3110_con_receive(max);
+			mutex_unlock(&max->thread_mutex);
+		}
 
 		set_current_state(TASK_INTERRUPTIBLE);
 		schedule_timeout(HZ / 20);
@@ -452,15 +490,16 @@ static int serial_m3110_startup(struct uart_port *port)
 	u16 config = 0;
 	int ret = 0;
 
-	if (port->line != 0)
+	if (port->line != 0) {
 		pr_err(PR_FMT "uart port startup failed\n");
+		return -1;
+	}
 
-	/* firstly disable all IRQ and config it to 115200, 8n1 */
+	/* Disable all IRQ and config it to 115200, 8n1 */
 	config = WC_TAG | WC_FIFO_ENABLE
 			| WC_1_STOPBITS
 			| WC_8BIT_WORD
 			| WC_BAUD_DR2;
-	ret = max3110_out(max, config);
 
 	/* as we use thread to handle tx/rx, need set low latency */
 	port->state->port.tty->low_latency = 1;
@@ -471,14 +510,30 @@ static int serial_m3110_startup(struct uart_port *port)
 	if (ret)
 		return ret;
 
-	/* enable RX IRQ only */
+	/* Enable RX IRQ only */
 	config |= WC_RXA_IRQ_ENABLE;
-	max3110_out(max, config);
 #else
-	/* if IRQ is disabled, start a read thread for input data */
+	/* If IRQ is disabled, start a read thread for input data */
 	max->read_thread =
 		kthread_run(max3110_read_thread, max, "max3110_read");
+	if (IS_ERR(max->read_thread)) {
+		ret = PTR_ERR(max->read_thread);
+		max->read_thread = NULL;
+		pr_err(PR_FMT "Can't create read thread!");
+		return ret;
+	}
+#endif
+
+	ret = max3110_out(max, config);
+	if (ret) {
+#ifdef CONFIG_MRST_MAX3110_IRQ
+		free_irq(max->irq, max);
+#else
+		kthread_stop(max->read_thread);
+		max->read_thread = NULL;
 #endif
+		return ret;
+	}
 
 	max->cur_conf = config;
 	return 0;
@@ -515,8 +570,7 @@ static int serial_m3110_request_port(struct uart_port *port)
 
 static void serial_m3110_config_port(struct uart_port *port, int flags)
 {
-	/* give it fake type */
-	port->type = PORT_PXA;
+	port->type = PORT_MAX3100;
 }
 
 static int
@@ -551,6 +605,9 @@ serial_m3110_set_termios(struct uart_port *port, struct ktermios *termios,
 		new_conf |= WC_7BIT_WORD;
 		break;
 	default:
+		/* We only support CS7 & CS8 */
+		termios->c_cflag &= ~CSIZE;
+		termios->c_cflag |= CS8;
 	case CS8:
 		cval = UART_LCR_WLEN8;
 		new_conf |= WC_8BIT_WORD;
@@ -559,7 +616,7 @@ serial_m3110_set_termios(struct uart_port *port, struct ktermios *termios,
 
 	baud = uart_get_baud_rate(port, termios, old, 0, 230400);
 
-	/* first calc the div for 1.8MHZ clock case */
+	/* First calc the div for 1.8MHZ clock case */
 	switch (baud) {
 	case 300:
 		clk_div = WC_BAUD_DR384;
@@ -595,7 +652,7 @@ serial_m3110_set_termios(struct uart_port *port, struct ktermios *termios,
 		if (max->clock & MAX3110_HIGH_CLK)
 			break;
 	default:
-		/* pick the previous baud rate */
+		/* Pick the previous baud rate */
 		baud = max->baud;
 		clk_div = max->cur_conf & WC_BAUD_DIV_MASK;
 		tty_termios_encode_baud_rate(termios, baud, baud);
@@ -603,15 +660,21 @@ serial_m3110_set_termios(struct uart_port *port, struct ktermios *termios,
 
 	if (max->clock & MAX3110_HIGH_CLK) {
 		clk_div += 1;
-		/* high clk version max3110 doesn't support B300 */
-		if (baud == 300)
+		/* High clk version max3110 doesn't support B300 */
+		if (baud == 300) {
 			baud = 600;
+			clk_div = WC_BAUD_DR384;
+		}
 		if (baud == 230400)
 			clk_div = WC_BAUD_DR1;
 		tty_termios_encode_baud_rate(termios, baud, baud);
 	}
 
 	new_conf = (new_conf & ~WC_BAUD_DIV_MASK) | clk_div;
+
+	if (unlikely(termios->c_cflag & CMSPAR))
+		termios->c_cflag &= ~CMSPAR;
+
 	if (termios->c_cflag & CSTOPB)
 		new_conf |= WC_2_STOPBITS;
 	else
@@ -631,13 +694,14 @@ serial_m3110_set_termios(struct uart_port *port, struct ktermios *termios,
 
 	new_conf |= WC_TAG;
 	if (new_conf != max->cur_conf) {
-		max3110_out(max, new_conf);
-		max->cur_conf = new_conf;
-		max->baud = baud;
+		if (!max3110_out(max, new_conf)) {
+			max->cur_conf = new_conf;
+			max->baud = baud;
+		}
 	}
 }
 
-/* don't handle hw handshaking */
+/* Don't handle hw handshaking */
 static unsigned int serial_m3110_get_mctrl(struct uart_port *port)
 {
 	return TIOCM_DSR | TIOCM_CAR | TIOCM_DSR;
@@ -671,7 +735,7 @@ struct uart_ops serial_m3110_ops = {
 	.break_ctl	= serial_m3110_break_ctl,
 	.startup	= serial_m3110_startup,
 	.shutdown	= serial_m3110_shutdown,
-	.set_termios	= serial_m3110_set_termios,	/* must have */
+	.set_termios	= serial_m3110_set_termios,
 	.pm		= serial_m3110_pm,
 	.type		= serial_m3110_type,
 	.release_port	= serial_m3110_release_port,
@@ -687,44 +751,52 @@ static struct uart_driver serial_m3110_reg = {
 	.major		= TTY_MAJOR,
 	.minor		= 64,
 	.nr		= 1,
-	.cons		= MRST_CONSOLE,
+	.cons		= &serial_m3110_console,
 };
 
+#ifdef CONFIG_PM
 static int serial_m3110_suspend(struct spi_device *spi, pm_message_t state)
 {
+	struct uart_max3110 *max = spi_get_drvdata(spi);
+
+	disable_irq(max->irq);
+	uart_suspend_port(&serial_m3110_reg, &max->port);
+	max3110_out(max, max->cur_conf | WC_SW_SHDI);
 	return 0;
 }
 
 static int serial_m3110_resume(struct spi_device *spi)
 {
+	struct uart_max3110 *max = spi_get_drvdata(spi);
+
+	max3110_out(max, max->cur_conf);
+	uart_resume_port(&serial_m3110_reg, &max->port);
+	enable_irq(max->irq);
 	return 0;
 }
+#else
+#define serial_m3110_suspend	NULL
+#define serial_m3110_resume	NULL
+#endif
 
-static struct dw_spi_chip spi0_uart = {
-	.poll_mode = 1,
-	.enable_dma = 0,
-	.type = SPI_FRF_SPI,
-};
-
-static int serial_m3110_probe(struct spi_device *spi)
+static int __devinit serial_m3110_probe(struct spi_device *spi)
 {
 	struct uart_max3110 *max;
-	int ret;
-	unsigned char *buffer;
+	void *buffer;
 	u16 res;
+	int ret = 0;
+
 	max = kzalloc(sizeof(*max), GFP_KERNEL);
 	if (!max)
 		return -ENOMEM;
 
-	/* set spi info */
-	spi->mode = SPI_MODE_0;
+	/* Set spi info */
 	spi->bits_per_word = 16;
 	max->clock = MAX3110_HIGH_CLK;
-	spi->controller_data = &spi0_uart;
 
 	spi_setup(spi);
 
-	max->port.type = PORT_PXA;	/* need apply for a max3110 type */
+	max->port.type = PORT_MAX3100;	/* need apply for a max3110 type */
 	max->port.fifosize = 2;		/* only have 16b buffer */
 	max->port.ops = &serial_m3110_ops;
 	max->port.line = 0;
@@ -732,7 +804,7 @@ static int serial_m3110_probe(struct spi_device *spi)
 	max->port.uartclk = 115200;
 
 	max->spi = spi;
-	max->name = spi->modalias;	/* use spi name as the name */
+	strcpy(max->name, spi->modalias);
 	max->irq = (u16)spi->irq;
 
 	mutex_init(&max->thread_mutex);
@@ -754,13 +826,15 @@ static int serial_m3110_probe(struct spi_device *spi)
 		ret = -ENODEV;
 		goto err_get_page;
 	}
-	buffer = (unsigned char *)__get_free_page(GFP_KERNEL);
+
+	buffer = (void *)__get_free_page(GFP_KERNEL);
 	if (!buffer) {
 		ret = -ENOMEM;
 		goto err_get_page;
 	}
-	max->con_xmit.buf = (unsigned char *)buffer;
-	max->con_xmit.head = max->con_xmit.tail = 0;
+	max->con_xmit.buf = buffer;
+	max->con_xmit.head = 0;
+	max->con_xmit.tail = 0;
 
 	max->main_thread = kthread_run(max3110_main_thread,
 					max, "max3110_main");
@@ -769,7 +843,9 @@ static int serial_m3110_probe(struct spi_device *spi)
 		goto err_kthread;
 	}
 
+	spi_set_drvdata(spi, max);
 	pmax = max;
+
 	/* give membase a psudo value to pass serial_core's check */
 	max->port.membase = (void *)0xff110000;
 	uart_add_one_port(&serial_m3110_reg, &max->port);
@@ -779,19 +855,17 @@ static int serial_m3110_probe(struct spi_device *spi)
 err_kthread:
 	free_page((unsigned long)buffer);
 err_get_page:
-	pmax = NULL;
 	kfree(max);
 	return ret;
 }
 
-static int max3110_remove(struct spi_device *dev)
+static int __devexit serial_m3110_remove(struct spi_device *dev)
 {
-	struct uart_max3110 *max = pmax;
+	struct uart_max3110 *max = spi_get_drvdata(dev);
 
-	if (!pmax)
+	if (!max)
 		return 0;
 
-	pmax = NULL;
 	uart_remove_one_port(&serial_m3110_reg, &max->port);
 
 	free_page((unsigned long)max->con_xmit.buf);
@@ -810,13 +884,12 @@ static struct spi_driver uart_max3110_driver = {
 			.owner	= THIS_MODULE,
 	},
 	.probe		= serial_m3110_probe,
-	.remove		= __devexit_p(max3110_remove),
+	.remove		= __devexit_p(serial_m3110_remove),
 	.suspend	= serial_m3110_suspend,
 	.resume		= serial_m3110_resume,
 };
 
-
-int __init serial_m3110_init(void)
+static int __init serial_m3110_init(void)
 {
 	int ret = 0;
 
@@ -831,7 +904,7 @@ int __init serial_m3110_init(void)
 	return ret;
 }
 
-void __exit serial_m3110_exit(void)
+static void __exit serial_m3110_exit(void)
 {
 	spi_unregister_driver(&uart_max3110_driver);
 	uart_unregister_driver(&serial_m3110_reg);
@@ -840,5 +913,5 @@ void __exit serial_m3110_exit(void)
 module_init(serial_m3110_init);
 module_exit(serial_m3110_exit);
 
-MODULE_LICENSE("GPL");
+MODULE_LICENSE("GPL v2");
 MODULE_ALIAS("max3110-uart");
diff --git a/drivers/serial/mrst_max3110.h b/drivers/serial/mrst_max3110.h
index 363478a..d1ef43a 100644
--- a/drivers/serial/mrst_max3110.h
+++ b/drivers/serial/mrst_max3110.h
@@ -56,4 +56,5 @@
 #define WC_BAUD_DR192		(0xE)
 #define WC_BAUD_DR384		(0xF)
 
+#define M3110_RX_FIFO_DEPTH	8
 #endif

[PATCH 5/5] mrst_max3110: Make the IRQ option runtime

[Alan Cox]

And while we are at it allow it to fail to find one. Without this the IRQ
option will cause the 3110 driver to fail on 0.7 SFI firmware.

Signed-off-by: Alan Cox <alan@linux.intel.com>
---

 drivers/serial/Kconfig        |    7 -----
 drivers/serial/mrst_max3110.c |   55 +++++++++++++++++++++--------------------
 2 files changed, 28 insertions(+), 34 deletions(-)


diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig
index 12900f7..ba4b390 100644
--- a/drivers/serial/Kconfig
+++ b/drivers/serial/Kconfig
@@ -717,13 +717,6 @@ config SERIAL_MRST_MAX3110
 	  the Intel Moorestown platform. On other systems use the max3100
 	  driver.
 
-config MRST_MAX3110_IRQ
-	boolean "Enable GPIO IRQ for Max3110 over Moorestown"
-	default n
-	depends on SERIAL_MRST_MAX3110 && GPIO_LANGWELL
-	help
-	  This has to be enabled after Moorestown GPIO driver is loaded
-
 config SERIAL_MFD_HSU
 	tristate "Medfield High Speed UART support"
 	depends on PCI
diff --git a/drivers/serial/mrst_max3110.c b/drivers/serial/mrst_max3110.c
index 880dce3..bae2697 100644
--- a/drivers/serial/mrst_max3110.c
+++ b/drivers/serial/mrst_max3110.c
@@ -446,7 +446,6 @@ static int max3110_main_thread(void *_max)
 	return ret;
 }
 
-#ifdef CONFIG_MRST_MAX3110_IRQ
 static irqreturn_t serial_m3110_irq(int irq, void *dev_id)
 {
 	struct uart_max3110 *max = dev_id;
@@ -458,7 +457,7 @@ static irqreturn_t serial_m3110_irq(int irq, void *dev_id)
 
 	return IRQ_HANDLED;
 }
-#else
+
 /* if don't use RX IRQ, then need a thread to polling read */
 static int max3110_read_thread(void *_max)
 {
@@ -481,7 +480,6 @@ static int max3110_read_thread(void *_max)
 
 	return 0;
 }
-#endif
 
 static int serial_m3110_startup(struct uart_port *port)
 {
@@ -504,34 +502,38 @@ static int serial_m3110_startup(struct uart_port *port)
 	/* as we use thread to handle tx/rx, need set low latency */
 	port->state->port.tty->low_latency = 1;
 
-#ifdef CONFIG_MRST_MAX3110_IRQ
-	ret = request_irq(max->irq, serial_m3110_irq,
+	if (max->irq) {
+		max->read_thread = NULL;
+		ret = request_irq(max->irq, serial_m3110_irq,
 				IRQ_TYPE_EDGE_FALLING, "max3110", max);
-	if (ret)
-		return ret;
+		if (ret) {
+			max->irq = 0;
+			pr_err(PR_FMT "unable to allocate IRQ, polling\n");
+		}  else {
+			/* Enable RX IRQ only */
+			config |= WC_RXA_IRQ_ENABLE;
+		}
+	}
 
-	/* Enable RX IRQ only */
-	config |= WC_RXA_IRQ_ENABLE;
-#else
-	/* If IRQ is disabled, start a read thread for input data */
-	max->read_thread =
-		kthread_run(max3110_read_thread, max, "max3110_read");
-	if (IS_ERR(max->read_thread)) {
-		ret = PTR_ERR(max->read_thread);
-		max->read_thread = NULL;
-		pr_err(PR_FMT "Can't create read thread!");
-		return ret;
+	if (max->irq == 0) {
+		/* If IRQ is disabled, start a read thread for input data */
+		max->read_thread =
+			kthread_run(max3110_read_thread, max, "max3110_read");
+		if (IS_ERR(max->read_thread)) {
+			ret = PTR_ERR(max->read_thread);
+			max->read_thread = NULL;
+			pr_err(PR_FMT "Can't create read thread!\n");
+			return ret;
+		}
 	}
-#endif
 
 	ret = max3110_out(max, config);
 	if (ret) {
-#ifdef CONFIG_MRST_MAX3110_IRQ
-		free_irq(max->irq, max);
-#else
-		kthread_stop(max->read_thread);
+		if (max->irq)
+			free_irq(max->irq, max);
+		if (max->read_thread)
+			kthread_stop(max->read_thread);
 		max->read_thread = NULL;
-#endif
 		return ret;
 	}
 
@@ -550,9 +552,8 @@ static void serial_m3110_shutdown(struct uart_port *port)
 		max->read_thread = NULL;
 	}
 
-#ifdef CONFIG_MRST_MAX3110_IRQ
-	free_irq(max->irq, max);
-#endif
+	if (max->irq)
+		free_irq(max->irq, max);
 
 	/* Disable interrupts from this port */
 	config = WC_TAG | WC_SW_SHDI;

Re: [PATCH 2/5] hsu, earlyprintk: add early printk for hsu_port2 console

[Alan Cox]

> Please Cc: x86 patches to the x86 maintainers.

Sure - I should probably have also cc'd Feng - I've forwarded it and
added Feng so it doesn't get missed.

> > +static int hsu_inited;
> 
> 'initialized' is the proper English word i think.

Then we should probably run /sbin/initialize in future ;) inited is
perfectly fine computerspeak and much less typing.

> > +static void early_hsu_init(void)
> > +{
> > +	u8 lcr;
> > +
> > +	if (phsu && hsu_inited)
> > +		return;
> 
> Surely one of those will suffice as a "have we initialized" flag?
> 
> Also, under what circumstances can we call early_hsu_init() twice?

Don't think we can

> > +	/* GPIO workaround */
> > +	set_fixmap_nocache(FIX_EARLYCON_MEM_BASE,
> > MFD_GPIO_HSU_REG);
> > +	phsu = (void *)(__fix_to_virt(FIX_EARLYCON_MEM_BASE) +
> > +			(MFD_GPIO_HSU_REG & (PAGE_SIZE - 1)));
> > +
> > +	*((u32 *)phsu) = 0x55465;
> 
> What does 0x55465 stand for?

It's a firmware fixup. Its a magic value (even to most of us who work
here ;)). Feng - am I right in thinking we don't need that anyway with
the current firmware ?

> > +{
> > +	unsigned int timeout = 10000; /* 10ms*/
> > +	u8 status;
> > +
> > +	while (timeout--) {
> > +		status = readb(phsu + UART_LSR);
> > +		if (status & BOTH_EMPTY)
> > +			break;
> > +
> > +		udelay(1);
> > +	}
> > +
> > +	if (timeout == 0xffffffff)
> > +		return;
> 
> Using the -1 literal will dtrt too, and will be slightly clearer to
> the potentially overworked reader of such patches.

If they have a degree in C sign propagation. Better is probably 

	while (--timeout) {..
	}

Re: [PATCH 2/5] hsu, earlyprintk: add early printk for hsu_port2 console

[Ingo Molnar]

* Alan Cox <alan@linux.intel.com> wrote:

> From: Feng Tang <feng.tang@intel.com>
> 
> To enable early printk of HSU console, simply set "earlyprint=hsu" in
> kernel command line.
> 
> Currently we put the code in the mrst_earlyprintk.c and it need enable
> CONFIG_X86_MRST_EARLY_PRINTK config option
> 
> Signed-off-by: Feng Tang <feng.tang@intel.com>
> Signed-off-by: Alan Cox <alan@linux.intel.com>
> ---
> 
>  arch/x86/include/asm/mrst.h        |    1 
>  arch/x86/kernel/early_printk.c     |    3 +
>  arch/x86/kernel/mrst_earlyprintk.c |  128 ++++++++++++++++++++++++++++++++++++
>  3 files changed, 132 insertions(+), 0 deletions(-)

Please Cc: x86 patches to the x86 maintainers.

> diff --git a/arch/x86/include/asm/mrst.h b/arch/x86/include/asm/mrst.h
> index 704d2fd..b6531da 100644
> --- a/arch/x86/include/asm/mrst.h
> +++ b/arch/x86/include/asm/mrst.h
> @@ -46,5 +46,6 @@ extern enum mrst_timer_options mrst_timer_options;
>  #define SFI_MRTC_MAX	8
>  
>  extern struct console early_mrst_console;
> +extern struct console early_hsu_console;
>  extern void mrst_early_printk(const char *fmt, ...);
>  #endif /* _ASM_X86_MRST_H */
> diff --git a/arch/x86/kernel/early_printk.c b/arch/x86/kernel/early_printk.c
> index 435a070..fd095e7 100644
> --- a/arch/x86/kernel/early_printk.c
> +++ b/arch/x86/kernel/early_printk.c
> @@ -243,6 +243,9 @@ static int __init setup_early_printk(char *buf)
>  #ifdef CONFIG_X86_MRST_EARLY_PRINTK
>  		if (!strncmp(buf, "mrst", 4))
>  			early_console_register(&early_mrst_console, keep);
> +
> +		if (!strncmp(buf, "hsu", 3))
> +			early_console_register(&early_hsu_console, keep);
>  #endif
>  		buf++;
>  	}
> diff --git a/arch/x86/kernel/mrst_earlyprintk.c b/arch/x86/kernel/mrst_earlyprintk.c
> index 4aff765..1fb1305 100644
> --- a/arch/x86/kernel/mrst_earlyprintk.c
> +++ b/arch/x86/kernel/mrst_earlyprintk.c
> @@ -9,9 +9,12 @@
>   * of the License.
>   */
>  
> +#include <linux/serial_reg.h>
> +#include <linux/serial_mfd.h>
>  #include <linux/kmsg_dump.h>
>  #include <linux/console.h>
>  #include <linux/kernel.h>
> +#include <linux/delay.h>
>  #include <linux/init.h>
>  #include <linux/io.h>
>  
> @@ -281,3 +284,128 @@ void mrst_early_printk(const char *fmt, ...)
>  
>  	early_mrst_console.write(&early_mrst_console, buf, n);
>  }
> +
> +
> +/* Will use HSU port2 for early console */
> +
> +/*
> + * Note:
> + * 1. still need GPIO workaround for UART2
> + *
> + */
> +static spinlock_t hsu_lock;

Please use DEFINE_SPINLOCK().

> +static int hsu_inited;

'initialized' is the proper English word i think.

> +static void __iomem *phsu;
> +#define HSU_PORT2_PADDR		0xffa28180

Newline undersupply.

(Please use newlines to separate blocks of different types of 
definitions.)

> +#define MFD_GPIO_HSU_REG	0xff12c064

> +
> +static void early_hsu_init(void)
> +{
> +	u8 lcr;
> +
> +	if (phsu && hsu_inited)
> +		return;

Surely one of those will suffice as a "have we initialized" flag?

Also, under what circumstances can we call early_hsu_init() twice?

> +
> +	spin_lock_init(&hsu_lock);

Can be removed if it's DEFINE_SPINLOCK() declared.

> +
> +	/* GPIO workaround */
> +	set_fixmap_nocache(FIX_EARLYCON_MEM_BASE, MFD_GPIO_HSU_REG);
> +	phsu = (void *)(__fix_to_virt(FIX_EARLYCON_MEM_BASE) +
> +			(MFD_GPIO_HSU_REG & (PAGE_SIZE - 1)));
> +
> +	*((u32 *)phsu) = 0x55465;

What does 0x55465 stand for?

> +
> +	set_fixmap_nocache(FIX_EARLYCON_MEM_BASE, HSU_PORT2_PADDR);
> +	phsu = (void *)(__fix_to_virt(FIX_EARLYCON_MEM_BASE) +
> +			(HSU_PORT2_PADDR & (PAGE_SIZE - 1)));
> +
> +	writeb(0x0, phsu + UART_FCR);
> +
> +	/* set to default 115200 */
> +	lcr = readb(phsu + UART_LCR);
> +	writeb((0x80 | lcr), phsu + UART_LCR);
> +	writeb(0x18, phsu + UART_DLL);
> +	writeb(lcr,  phsu + UART_LCR);
> +	writel(0x3600, phsu + UART_MUL*4);
> +
> +	writeb(0x8, phsu + UART_MCR);
> +	writeb(0x7, phsu + UART_FCR);
> +	writeb(0x3, phsu + UART_LCR);
> +
> +	/* clear IRQ status */
> +	readb(phsu + UART_LSR);
> +	readb(phsu + UART_RX);
> +	readb(phsu + UART_IIR);
> +	readb(phsu + UART_MSR);
> +
> +
> +

Newline oversupply.

> +	writeb(0x7, phsu + UART_FCR);
> +
> +	hsu_inited = 1;
> +}
> +
> +#define BOTH_EMPTY (UART_LSR_TEMT | UART_LSR_THRE)
> +static void early_hsu_putc(char ch)

Newline undersupply.

> +{
> +	unsigned int timeout = 10000; /* 10ms*/
> +	u8 status;
> +
> +	while (timeout--) {
> +		status = readb(phsu + UART_LSR);
> +		if (status & BOTH_EMPTY)
> +			break;
> +
> +		udelay(1);
> +	}
> +
> +	if (timeout == 0xffffffff)
> +		return;

Using the -1 literal will dtrt too, and will be slightly clearer to the 
potentially overworked reader of such patches.

> +
> +	writeb(ch, phsu + UART_TX);
> +}
> +
> +static void early_hsu_write(struct console *con,
> +			const char *str, unsigned n)

Unnecessary linebreak. Ignore checkpatch when it suggests crap.

> +{
> +	int  i;

Space character oversupply.

> +	unsigned long flags;
> +
> +	/*
> +	printk("%s(): enter\n\n", __func__);
> +	*/

Can go away i suspect.

> +
> +	if (unlikely(!hsu_inited))
> +		early_hsu_init();

We check the 'hsu_inited' flag in early_hsu_init() too. One of the 
checks is superfluous.

> +
> +	spin_lock_irqsave(&hsu_lock, flags);

In early_printk code we generally try to avoid the use of spinlocks.

It is a 'console of last resort', and we try to keep it as simple as 
possible. The current early_printk.c code does not have a single 
spinlock, and still it's robust and usable in a wide range of 
circumstances, is NMI safe, etc.

With allowing early_hsu_putc() to execute in parallel, we at most can 
lose a character, because the UART's BOTH_EMPTY state might be stale. 
But it's not a real issue in practice: default earlyprintk is turned off 
way before SMP initializes.

> +	for (i = 0; i < n && *str; i++) {
> +		if (*str == '\n')
> +			early_hsu_putc('\r');
> +		early_hsu_putc(*str);
> +
> +		str++;
> +	}
> +	spin_unlock_irqrestore(&hsu_lock, flags);
> +}
> +
> +
> +struct console early_hsu_console = {
> +	.name =		"earlyhsu",
> +	.write =	early_hsu_write,
> +	.flags =	CON_PRINTBUFFER,
> +	.index =	-1,
> +};
> +
> +void hsu_early_printk(const char *fmt, ...)
> +{
> +	char buf[512];
> +	int n;
> +	va_list ap;
> +
> +	va_start(ap, fmt);
> +	n = vscnprintf(buf, 512, fmt, ap);
> +	va_end(ap);
> +
> +	early_hsu_console.write(&early_mrst_console, buf, n);
> +}

Instead of this hack that duplicates much of early_printk() please add 
something like:

  extern void __earlyprintk(struct console *con, ...)

and then hsa_early_printk() becomes:

  #define hsu_early_printk(x...) __early_printk(&earlymrst_console, x...)

... or so - and other subsystems may make use of it as well, to 
implement their own special unconditional-printout routines.

Thanks,

	Ingo

Re: [PATCH 2/5] hsu, earlyprintk: add early printk for hsu_port2 console

[Ingo Molnar]

* Alan Cox <alan@linux.intel.com> wrote:

> > Please Cc: x86 patches to the x86 maintainers.
> 
> Sure - I should probably have also cc'd Feng - I've forwarded it and
> added Feng so it doesn't get missed.

thx.

> > > +static int hsu_inited;
> > 
> > 'initialized' is the proper English word i think.
> 
> Then we should probably run /sbin/initialize in future ;) [...]

Fortunately there's no /sbin/inited.

> [...] inited is perfectly fine computerspeak and much less typing.

It's a distinctly annoying grammar mistake (to me at least) and it only 
comes up very rarely in the kernel - which has its fair share of 
annoying grammar otherwise.

As per a quick & dirty 'git grep' run we have 4267 (96%) instances of 
'initialized' and only 174 (4%) 'inited' instances usage right now.

hsu_init_done might be a compromise?

But ... no strong feelings in any case. If you the native speaker are 
not annoyed by reading 'inited' then i guess i'm in the minority.

> > > +static void early_hsu_init(void)
> > > +{
> > > +	u8 lcr;
> > > +
> > > +	if (phsu && hsu_inited)
> > > +		return;
> > 
> > Surely one of those will suffice as a "have we initialized" flag?
> > 
> > Also, under what circumstances can we call early_hsu_init() twice?
> 
> Don't think we can
> 
> > > +	/* GPIO workaround */
> > > +	set_fixmap_nocache(FIX_EARLYCON_MEM_BASE,
> > > MFD_GPIO_HSU_REG);
> > > +	phsu = (void *)(__fix_to_virt(FIX_EARLYCON_MEM_BASE) +
> > > +			(MFD_GPIO_HSU_REG & (PAGE_SIZE - 1)));
> > > +
> > > +	*((u32 *)phsu) = 0x55465;
> > 
> > What does 0x55465 stand for?
> 
> It's a firmware fixup. Its a magic value (even to most of us who work 
> here ;)). Feng - am I right in thinking we don't need that anyway with 
> the current firmware ?

If it's some magic number it's worth symbolizing it - keeping future 
generations of happy mrst hackers from wondering at that incantation.

> 
> > > +{
> > > +	unsigned int timeout = 10000; /* 10ms*/
> > > +	u8 status;
> > > +
> > > +	while (timeout--) {
> > > +		status = readb(phsu + UART_LSR);
> > > +		if (status & BOTH_EMPTY)
> > > +			break;
> > > +
> > > +		udelay(1);
> > > +	}
> > > +
> > > +	if (timeout == 0xffffffff)
> > > +		return;
> > 
> > Using the -1 literal will dtrt too, and will be slightly clearer to
> > the potentially overworked reader of such patches.
> 
> If they have a degree in C sign propagation.

My 8yo son knows it that the next number below zero is -1, and he 
distinctly has no degree in C sign propagation rules. But you are right 
to point out the correct solution:

> [...] Better is probably 
> 
> 	while (--timeout) {..
> 	}

indeed.

Thanks,

	Ingo

Re: [PATCH 2/5] hsu, earlyprintk: add early printk for hsu_port2 console

[Feng Tang]

On Mon, 6 Sep 2010 22:15:42 +0800
Alan Cox <alan@linux.intel.com> wrote:

> 
> > > +	/* GPIO workaround */
> > > +	set_fixmap_nocache(FIX_EARLYCON_MEM_BASE,
> > > MFD_GPIO_HSU_REG);
> > > +	phsu = (void *)(__fix_to_virt(FIX_EARLYCON_MEM_BASE) +
> > > +			(MFD_GPIO_HSU_REG & (PAGE_SIZE - 1)));
> > > +
> > > +	*((u32 *)phsu) = 0x55465;
> > 
> > What does 0x55465 stand for?
> 
> It's a firmware fixup. Its a magic value (even to most of us who work
> here ;)). Feng - am I right in thinking we don't need that anyway with
> the current firmware ?

Yes, it's a fixup for firmware, it set GPIO controller's register to correctly
configure the GPIO lines used by HSU. Latest firmware already fix that, and
it could be removed.

Thank you both for the comments, will try to address them and make a v2.

Thanks,
Feng