target/linux/brcm63xx/patches-3.8/106-spi-bcm63xx-reject-transfers-unable-to-transfer.patch

   1 From 243970ea035623f70431a80ece802f572cd446be Mon Sep 17 00:00:00 2001
   2 From: Jonas Gorski <jogo@openwrt.org>
   3 Date: Sun, 9 Dec 2012 00:10:00 +0100
   4 Subject: [PATCH V2 1/2] spi/bcm63xx: reject transfers unable to transfer
   5
   6 The hardware does not support keeping CS asserted after sending one
   7 FIFO buffer worth of data, so reject transfers requiring CS being kept
   8 asserted, either between transers or for a certain time after it,
   9 or exceeding the FIFO size.
  10
  11 Signed-off-by: Jonas Gorski <jogo@openwrt.org>
  12 ---
  13  drivers/spi/spi-bcm63xx.c |   91 +++++++++++++++++++++------------------------
  14  1 file changed, 42 insertions(+), 49 deletions(-)
  15
  16 --- a/drivers/spi/spi-bcm63xx.c
  17 +++ b/drivers/spi/spi-bcm63xx.c
  18 @@ -49,16 +49,10 @@ struct bcm63xx_spi {
  19         unsigned int            msg_type_shift;
  20         unsigned int            msg_ctl_width;
  21
  22 -       /* Data buffers */
  23 -       const unsigned char     *tx_ptr;
  24 -       unsigned char           *rx_ptr;
  25 -
  26         /* data iomem */
  27         u8 __iomem              *tx_io;
  28         const u8 __iomem        *rx_io;
  29
  30 -       int                     remaining_bytes;
  31 -
  32         struct clk              *clk;
  33         struct platform_device  *pdev;
  34  };
  35 @@ -175,24 +169,13 @@ static int bcm63xx_spi_setup(struct spi_
  36         return 0;
  37  }
  38
  39 -/* Fill the TX FIFO with as many bytes as possible */
  40 -static void bcm63xx_spi_fill_tx_fifo(struct bcm63xx_spi *bs)
  41 -{
  42 -       u8 size;
  43 -
  44 -       /* Fill the Tx FIFO with as many bytes as possible */
  45 -       size = bs->remaining_bytes < bs->fifo_size ? bs->remaining_bytes :
  46 -               bs->fifo_size;
  47 -       memcpy_toio(bs->tx_io, bs->tx_ptr, size);
  48 -       bs->remaining_bytes -= size;
  49 -}
  50 -
  51 -static unsigned int bcm63xx_txrx_bufs(struct spi_device *spi,
  52 -                                       struct spi_transfer *t)
  53 +static int bcm63xx_txrx_bufs(struct spi_device *spi, struct spi_transfer *t)
  54  {
  55         struct bcm63xx_spi *bs = spi_master_get_devdata(spi->master);
  56         u16 msg_ctl;
  57         u16 cmd;
  58 +       u8 rx_tail;
  59 +       unsigned int timeout = 0;
  60
  61         /* Disable the CMD_DONE interrupt */
  62         bcm_spi_writeb(bs, 0, SPI_INT_MASK);
  63 @@ -200,14 +183,8 @@ static unsigned int bcm63xx_txrx_bufs(st
  64         dev_dbg(&spi->dev, "txrx: tx %p, rx %p, len %d\n",
  65                 t->tx_buf, t->rx_buf, t->len);
  66
  67 -       /* Transmitter is inhibited */
  68 -       bs->tx_ptr = t->tx_buf;
  69 -       bs->rx_ptr = t->rx_buf;
  70 -
  71 -       if (t->tx_buf) {
  72 -               bs->remaining_bytes = t->len;
  73 -               bcm63xx_spi_fill_tx_fifo(bs);
  74 -       }
  75 +       if (t->tx_buf)
  76 +               memcpy_toio(bs->tx_io, t->tx_buf, t->len);
  77
  78         init_completion(&bs->done);
  79
  80 @@ -239,7 +216,18 @@ static unsigned int bcm63xx_txrx_bufs(st
  81         /* Enable the CMD_DONE interrupt */
  82         bcm_spi_writeb(bs, SPI_INTR_CMD_DONE, SPI_INT_MASK);
  83
  84 -       return t->len - bs->remaining_bytes;
  85 +       timeout = wait_for_completion_timeout(&bs->done, HZ);
  86 +       if (!timeout)
  87 +               return -ETIMEDOUT;
  88 +
  89 +       /* read out all data */
  90 +       rx_tail = bcm_spi_readb(bs, SPI_RX_TAIL);
  91 +
  92 +       /* Read out all the data */
  93 +       if (rx_tail)
  94 +               memcpy_fromio(t->rx_ptr, bs->rx_io, rx_tail);
  95 +
  96 +       return 0;
  97  }
  98
  99  static int bcm63xx_spi_prepare_transfer(struct spi_master *master)
 100 @@ -267,36 +255,41 @@ static int bcm63xx_spi_transfer_one(stru
 101         struct spi_transfer *t;
 102         struct spi_device *spi = m->spi;
 103         int status = 0;
 104 -       unsigned int timeout = 0;
 105
 106         list_for_each_entry(t, &m->transfers, transfer_list) {
 107 -               unsigned int len = t->len;
 108 -               u8 rx_tail;
 109 -
 110                 status = bcm63xx_spi_check_transfer(spi, t);
 111                 if (status < 0)
 112                         goto exit;
 113
 114 +               /* we can only transfer one fifo worth of data */
 115 +               if (t->len > bs->fifo_size) {
 116 +                       dev_err(&spi->dev, "unable to do transfers larger than FIFO size (%i > %i)\n",
 117 +                               t->len, bs->fifo_size);
 118 +                       status = -EINVAL;
 119 +                       goto exit;
 120 +               }
 121 +
 122 +               /* CS will be deasserted directly after transfer */
 123 +               if (t->delay_usecs) {
 124 +                       dev_err(&spi->dev, "unable to keep CS asserted after transfer\n");
 125 +                       status = -EINVAL;
 126 +                       goto exit;
 127 +               }
 128 +
 129 +               if (!t->cs_change &&
 130 +                   !list_is_last(&t->transfer_list, &m->transfers)) {
 131 +                       dev_err(&spi->dev, "unable to keep CS asserted between transfers\n");
 132 +                       status = -EINVAL;
 133 +                       goto exit;
 134 +               }
 135 +
 136                 /* configure adapter for a new transfer */
 137                 bcm63xx_spi_setup_transfer(spi, t);
 138
 139 -               while (len) {
 140 -                       /* send the data */
 141 -                       len -= bcm63xx_txrx_bufs(spi, t);
 142 -
 143 -                       timeout = wait_for_completion_timeout(&bs->done, HZ);
 144 -                       if (!timeout) {
 145 -                               status = -ETIMEDOUT;
 146 -                               goto exit;
 147 -                       }
 148 -
 149 -                       /* read out all data */
 150 -                       rx_tail = bcm_spi_readb(bs, SPI_RX_TAIL);
 151 -
 152 -                       /* Read out all the data */
 153 -                       if (rx_tail)
 154 -                               memcpy_fromio(bs->rx_ptr, bs->rx_io, rx_tail);
 155 -               }
 156 +               /* send the data */
 157 +               status = bcm63xx_txrx_bufs(spi, t);
 158 +               if (status)
 159 +                       goto exit;
 160
 161                 m->actual_length += t->len;
 162         }