1 files changed, 68 insertions, 9 deletions

diff --git a/drivers/char/synclink_gt.c b/drivers/char/synclink_gt.c
index 67986ea0d479..1386625fc4ca 100644
--- a/drivers/char/synclink_gt.c
+++ b/drivers/char/synclink_gt.c
@@ -214,6 +214,7 @@ struct slgt_desc
 #define set_desc_next(a,b) (a).next   = cpu_to_le32((unsigned int)(b))
 #define set_desc_count(a,b)(a).count  = cpu_to_le16((unsigned short)(b))
 #define set_desc_eof(a,b)  (a).status = cpu_to_le16((b) ? (le16_to_cpu((a).status) | BIT0) : (le16_to_cpu((a).status) & ~BIT0))
+#define set_desc_status(a, b) (a).status = cpu_to_le16((unsigned short)(b))
 #define desc_count(a)      (le16_to_cpu((a).count))
 #define desc_status(a)     (le16_to_cpu((a).status))
 #define desc_complete(a)   (le16_to_cpu((a).status) & BIT15)
@@ -297,6 +298,7 @@ struct slgt_info {
         u32 max_frame_size;       /* as set by device config */
 
         unsigned int rbuf_fill_level;
+        unsigned int rx_pio;
         unsigned int if_mode;
         unsigned int base_clock;
 
@@ -331,6 +333,8 @@ struct slgt_info {
         struct slgt_desc *rbufs;
         unsigned int rbuf_current;
         unsigned int rbuf_index;
+        unsigned int rbuf_fill_index;
+        unsigned short rbuf_fill_count;
 
         unsigned int tbuf_count;
         struct slgt_desc *tbufs;
@@ -2110,6 +2114,40 @@ static void ri_change(struct slgt_info *info, unsigned short status)
         info->pending_bh |= BH_STATUS;
 }
 
+static void isr_rxdata(struct slgt_info *info)
+{
+        unsigned int count = info->rbuf_fill_count;
+        unsigned int i = info->rbuf_fill_index;
+        unsigned short reg;
+
+        while (rd_reg16(info, SSR) & IRQ_RXDATA) {
+                reg = rd_reg16(info, RDR);
+                DBGISR(("isr_rxdata %s RDR=%04X\n", info->device_name, reg));
+                if (desc_complete(info->rbufs[i])) {
+                        /* all buffers full */
+                        rx_stop(info);
+                        info->rx_restart = 1;
+                        continue;
+                }
+                info->rbufs[i].buf[count++] = (unsigned char)reg;
+                /* async mode saves status byte to buffer for each data byte */
+                if (info->params.mode == MGSL_MODE_ASYNC)
+                        info->rbufs[i].buf[count++] = (unsigned char)(reg >> 8);
+                if (count == info->rbuf_fill_level || (reg & BIT10)) {
+                        /* buffer full or end of frame */
+                        set_desc_count(info->rbufs[i], count);
+                        set_desc_status(info->rbufs[i], BIT15 | (reg >> 8));
+                        info->rbuf_fill_count = count = 0;
+                        if (++i == info->rbuf_count)
+                                i = 0;
+                        info->pending_bh |= BH_RECEIVE;
+                }
+        }
+
+        info->rbuf_fill_index = i;
+        info->rbuf_fill_count = count;
+}
+
 static void isr_serial(struct slgt_info *info)
 {
         unsigned short status = rd_reg16(info, SSR);
@@ -2125,6 +2163,8 @@ static void isr_serial(struct slgt_info *info)
                         if (info->tx_count)
                                 isr_txeom(info, status);
                 }
+                if (info->rx_pio && (status & IRQ_RXDATA))
+                        isr_rxdata(info);
                 if ((status & IRQ_RXBREAK) && (status & RXBREAK)) {
                         info->icount.brk++;
                         /* process break detection if tty control allows */
@@ -2141,7 +2181,8 @@ static void isr_serial(struct slgt_info *info)
         } else {
                 if (status & (IRQ_TXIDLE + IRQ_TXUNDER))
                         isr_txeom(info, status);
-
+                if (info->rx_pio && (status & IRQ_RXDATA))
+                        isr_rxdata(info);
                 if (status & IRQ_RXIDLE) {
                         if (status & RXIDLE)
                                 info->icount.rxidle++;
@@ -2642,6 +2683,10 @@ static int rx_enable(struct slgt_info *info, int enable)
                         return -EINVAL;
                 }
                 info->rbuf_fill_level = rbuf_fill_level;
+                if (rbuf_fill_level < 128)
+                        info->rx_pio = 1; /* PIO mode */
+                else
+                        info->rx_pio = 0; /* DMA mode */
                 rx_stop(info); /* restart receiver to use new fill level */
         }
 
@@ -3844,15 +3889,27 @@ static void rx_start(struct slgt_info *info)
         rdma_reset(info);
         reset_rbufs(info);
 
-        /* set 1st descriptor address */
-        wr_reg32(info, RDDAR, info->rbufs[0].pdesc);
-
-        if (info->params.mode != MGSL_MODE_ASYNC) {
-                /* enable rx DMA and DMA interrupt */
-                wr_reg32(info, RDCSR, (BIT2 + BIT0));
+        if (info->rx_pio) {
+                /* rx request when rx FIFO not empty */
+                wr_reg16(info, SCR, (unsigned short)(rd_reg16(info, SCR) & ~BIT14));
+                slgt_irq_on(info, IRQ_RXDATA);
+                if (info->params.mode == MGSL_MODE_ASYNC) {
+                        /* enable saving of rx status */
+                        wr_reg32(info, RDCSR, BIT6);
+                }
         } else {
-                /* enable saving of rx status, rx DMA and DMA interrupt */
-                wr_reg32(info, RDCSR, (BIT6 + BIT2 + BIT0));
+                /* rx request when rx FIFO half full */
+                wr_reg16(info, SCR, (unsigned short)(rd_reg16(info, SCR) | BIT14));
+                /* set 1st descriptor address */
+                wr_reg32(info, RDDAR, info->rbufs[0].pdesc);
+
+                if (info->params.mode != MGSL_MODE_ASYNC) {
+                        /* enable rx DMA and DMA interrupt */
+                        wr_reg32(info, RDCSR, (BIT2 + BIT0));
+                } else {
+                        /* enable saving of rx status, rx DMA and DMA interrupt */
+                        wr_reg32(info, RDCSR, (BIT6 + BIT2 + BIT0));
+                }
         }
 
         slgt_irq_on(info, IRQ_RXOVER);
@@ -4470,6 +4527,8 @@ static void free_rbufs(struct slgt_info *info, unsigned int i, unsigned int last
 static void reset_rbufs(struct slgt_info *info)
 {
         free_rbufs(info, 0, info->rbuf_count - 1);
+        info->rbuf_fill_index = 0;
+        info->rbuf_fill_count = 0;
 }
 
 /*