1 files changed, 216 insertions, 142 deletions

diff --git a/drivers/serial/mrst_max3110.c b/drivers/serial/mrst_max3110.c
index 51c15f58e01e..b62857bf2fdb 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) 2008-2010, 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,
@@ -32,18 +32,13 @@
 #include <linux/irq.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"
 
@@ -56,7 +51,7 @@
 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;
@@ -67,35 +62,30 @@ 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;
@@ -104,7 +94,7 @@ 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;
 
@@ -113,58 +103,80 @@ 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;
 }
 
@@ -178,10 +190,6 @@ 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);
 }
 
 /*
@@ -197,6 +205,9 @@ 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
@@ -210,6 +221,9 @@ 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;
@@ -240,8 +254,6 @@ 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;
@@ -259,32 +271,44 @@ 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)
@@ -294,6 +318,8 @@ static inline void send_circ_buf(struct uart_max3110 *max,
                         left -= len;
                 }
         }
+
+        kfree(buf);
 }
 
 static void transmit_char(struct uart_max3110 *max)
@@ -313,8 +339,10 @@ 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 =
@@ -336,7 +364,7 @@ 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);
@@ -344,32 +372,37 @@ 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;
@@ -397,7 +430,7 @@ 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))
@@ -414,7 +447,6 @@ 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;
@@ -426,7 +458,7 @@ 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)
 {
@@ -434,9 +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);
@@ -444,7 +481,6 @@ static int max3110_read_thread(void *_max)
 
         return 0;
 }
-#endif
 
 static int serial_m3110_startup(struct uart_port *port)
 {
@@ -453,33 +489,54 @@ 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;
 
-#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;
-        max3110_out(max, config);
-#else
-        /* if IRQ is disabled, start a read thread for input data */
-        max->read_thread =
-                kthread_run(max3110_read_thread, max, "max3110_read");
-#endif
+        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;
+                }
+        }
+
+        ret = max3110_out(max, config);
+        if (ret) {
+                if (max->irq)
+                        free_irq(max->irq, max);
+                if (max->read_thread)
+                        kthread_stop(max->read_thread);
+                max->read_thread = NULL;
+                return ret;
+        }
 
         max->cur_conf = config;
         return 0;
@@ -496,9 +553,8 @@ 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;
@@ -516,8 +572,7 @@ 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
@@ -552,6 +607,9 @@ 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;
@@ -560,7 +618,7 @@ 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;
@@ -596,7 +654,7 @@ 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);
@@ -604,15 +662,21 @@ 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
@@ -632,13 +696,14 @@ 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;
@@ -672,7 +737,7 @@ 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,
@@ -688,52 +753,60 @@ 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.fifosize = 2;         /* only have 16b buffer */
+        max->port.type = PORT_MAX3100;
+        max->port.fifosize = 2;         /* Only have 16b buffer */
         max->port.ops = &serial_m3110_ops;
         max->port.line = 0;
         max->port.dev = &spi->dev;
         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);
@@ -755,13 +828,15 @@ 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");
@@ -770,8 +845,10 @@ 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 */
+
+        /* 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);
 
@@ -780,19 +857,17 @@ 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);
@@ -811,13 +886,12 @@ 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;
 
@@ -832,7 +906,7 @@ 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);
@@ -841,5 +915,5 @@ 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");