max3110: add sysrq support

This patch moves several occurences of similar code inside receive_chars(),
which now also takes care of checking for break and calling sysrq handling
code.

Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

2 files changed, 44 insertions, 56 deletions

diff --git a/drivers/tty/serial/mrst_max3110.c b/drivers/tty/serial/mrst_max3110.c
index c8f986876229..42aa43934b20 100644
--- a/drivers/tty/serial/mrst_max3110.c
+++ b/drivers/tty/serial/mrst_max3110.c
@@ -27,6 +27,10 @@
  *    interrupt for a low speed UART device
  */
 
+#ifdef CONFIG_MAGIC_SYSRQ
+#define SUPPORT_SYSRQ
+#endif
+
 #include <linux/module.h>
 #include <linux/ioport.h>
 #include <linux/irq.h>
@@ -73,9 +77,9 @@ struct uart_max3110 {
 /* global data structure, may need be removed */
 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, u8 *buf);
+static int receive_chars(struct uart_max3110 *max,
+                                unsigned short *str, int len);
+static int max3110_read_multi(struct uart_max3110 *max);
 static void max3110_con_receive(struct uart_max3110 *max);
 
 static int max3110_write_then_read(struct uart_max3110 *max,
@@ -108,7 +112,6 @@ static int max3110_out(struct uart_max3110 *max, const u16 out)
 {
         void *buf;
         u16 *obuf, *ibuf;
-        u8  ch;
         int ret;
 
         buf = kzalloc(8, GFP_KERNEL | GFP_DMA);
@@ -125,11 +128,7 @@ static int max3110_out(struct uart_max3110 *max, const u16 out)
                 goto exit;
         }
 
-        /* If some valid data is read back */
-        if (*ibuf & MAX3110_READ_DATA_AVAILABLE) {
-                ch = *ibuf & 0xff;
-                receive_chars(max, &ch, 1);
-        }
+        receive_chars(max, ibuf, 1);
 
 exit:
         kfree(buf);
@@ -142,12 +141,11 @@ exit:
  *
  * Return how many valide bytes are read back
  */
-static int max3110_read_multi(struct uart_max3110 *max, u8 *rxbuf)
+static int max3110_read_multi(struct uart_max3110 *max)
 {
         void *buf;
         u16 *obuf, *ibuf;
-        u8 *pbuf, valid_str[M3110_RX_FIFO_DEPTH];
-        int i, j, blen;
+        int ret, blen;
 
         blen = M3110_RX_FIFO_DEPTH * sizeof(u16);
         buf = kzalloc(blen * 2, GFP_KERNEL | GFP_DMA);
@@ -165,19 +163,10 @@ static int max3110_read_multi(struct uart_max3110 *max, u8 *rxbuf)
                 return 0;
         }
 
-        /* If caller doesn't provide a buffer, then handle received char */
-        pbuf = rxbuf ? rxbuf : valid_str;
-
-        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);
+        ret = receive_chars(max, ibuf, M3110_RX_FIFO_DEPTH);
 
         kfree(buf);
-        return j;
+        return ret;
 }
 
 static void serial_m3110_con_putchar(struct uart_port *port, int ch)
@@ -276,8 +265,7 @@ static void send_circ_buf(struct uart_max3110 *max,
 {
         void *buf;
         u16 *obuf, *ibuf;
-        u8 valid_str[WORDS_PER_XFER];
-        int i, j, len, blen, dma_size, left, ret = 0;
+        int i, len, blen, dma_size, left, ret = 0;
 
 
         dma_size = WORDS_PER_XFER * sizeof(u16) * 2;
@@ -307,13 +295,7 @@ static void send_circ_buf(struct uart_max3110 *max,
                                 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++] = ibuf[i] & 0xff;
-                        }
-
-                        if (j)
-                                receive_chars(max, valid_str, j);
+                        receive_chars(max, ibuf, len);
 
                         max->port.icount.tx += len;
                         left -= len;
@@ -353,30 +335,48 @@ static void serial_m3110_start_tx(struct uart_port *port)
                 wake_up(&max->wq);
 }
 
-static void receive_chars(struct uart_max3110 *max, unsigned char *str, int len)
+static int
+receive_chars(struct uart_max3110 *max, unsigned short *str, int len)
 {
         struct uart_port *port = &max->port;
         struct tty_struct *tty;
-        int usable;
+        char buf[M3110_RX_FIFO_DEPTH];
+        int r, w, usable;
 
         /* If uart is not opened, just return */
         if (!port->state)
-                return;
+                return 0;
 
         tty = port->state->port.tty;
         if (!tty)
-                return;
+                return 0;
+
+        for (r = 0, w = 0; r < len; r++) {
+                if (str[r] & MAX3110_BREAK &&
+                    uart_handle_break(port))
+                        continue;
+
+                if (str[r] & MAX3110_READ_DATA_AVAILABLE) {
+                        if (uart_handle_sysrq_char(port, str[r] & 0xff))
+                                continue;
+
+                        buf[w++] = str[r] & 0xff;
+                }
+        }
 
-        while (len) {
-                usable = tty_buffer_request_room(tty, len);
+        if (!w)
+                return 0;
+
+        for (r = 0; w; r += usable, w -= usable) {
+                usable = tty_buffer_request_room(tty, w);
                 if (usable) {
-                        tty_insert_flip_string(tty, str, usable);
-                        str += usable;
+                        tty_insert_flip_string(tty, buf + r, usable);
                         port->icount.rx += usable;
                 }
-                len -= usable;
         }
         tty_flip_buffer_push(tty);
+
+        return r;
 }
 
 /*
@@ -391,28 +391,15 @@ static void receive_chars(struct uart_max3110 *max, unsigned char *str, int len)
  */
 static void max3110_con_receive(struct uart_max3110 *max)
 {
-        int loop = 1, num, total = 0;
-        u8 recv_buf[512], *pbuf;
+        int loop = 1, num;
 
-        pbuf = recv_buf;
         do {
-                num = max3110_read_multi(max, pbuf);
+                num = max3110_read_multi(max);
 
                 if (num) {
                         loop = 5;
-                        pbuf += num;
-                        total += num;
-
-                        if (total >= 504) {
-                                receive_chars(max, recv_buf, total);
-                                pbuf = recv_buf;
-                                total = 0;
-                        }
                 }
         } while (--loop);
-
-        if (total)
-                receive_chars(max, recv_buf, total);
 }
 
 static int max3110_main_thread(void *_max)
diff --git a/drivers/tty/serial/mrst_max3110.h b/drivers/tty/serial/mrst_max3110.h
index c37ea48c825a..35af0739513b 100644
--- a/drivers/tty/serial/mrst_max3110.h
+++ b/drivers/tty/serial/mrst_max3110.h
@@ -7,6 +7,7 @@
 /* status bits for all 4 MAX3110 operate modes */
 #define MAX3110_READ_DATA_AVAILABLE     (1 << 15)
 #define MAX3110_WRITE_BUF_EMPTY         (1 << 14)
+#define MAX3110_BREAK                   (1 << 10)
 
 #define WC_TAG                  (3 << 14)
 #define RC_TAG                  (1 << 14)