drivers/spi/dw_spi_mid.c

   1 /*
   2  * dw_spi_mid.c - special handling for DW core on Intel MID platform
   3  *
   4  * Copyright (c) 2009, Intel Corporation.
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms and conditions of the GNU General Public License,
   8  * version 2, as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  13  * more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
  18  */
  19
  20 #include <linux/dma-mapping.h>
  21 #include <linux/dmaengine.h>
  22 #include <linux/interrupt.h>
  23 #include <linux/slab.h>
  24 #include <linux/spi/spi.h>
  25 #include <linux/spi/dw_spi.h>
  26
  27 #ifdef CONFIG_SPI_DW_MID_DMA
  28 #include <linux/intel_mid_dma.h>
  29 #include <linux/pci.h>
  30
  31 struct mid_dma {
  32         struct intel_mid_dma_slave      dmas_tx;
  33         struct intel_mid_dma_slave      dmas_rx;
  34 };
  35
  36 static bool mid_spi_dma_chan_filter(struct dma_chan *chan, void *param)
  37 {
  38         struct dw_spi *dws = param;
  39
  40         return dws->dmac && (&dws->dmac->dev == chan->device->dev);
  41 }
  42
  43 static int mid_spi_dma_init(struct dw_spi *dws)
  44 {
  45         struct mid_dma *dw_dma = dws->dma_priv;
  46         struct intel_mid_dma_slave *rxs, *txs;
  47         dma_cap_mask_t mask;
  48
  49         /*
  50          * Get pci device for DMA controller, currently it could only
  51          * be the DMA controller of either Moorestown or Medfield
  52          */
  53         dws->dmac = pci_get_device(PCI_VENDOR_ID_INTEL, 0x0813, NULL);
  54         if (!dws->dmac)
  55                 dws->dmac = pci_get_device(PCI_VENDOR_ID_INTEL, 0x0827, NULL);
  56
  57         dma_cap_zero(mask);
  58         dma_cap_set(DMA_SLAVE, mask);
  59
  60         /* 1. Init rx channel */
  61         dws->rxchan = dma_request_channel(mask, mid_spi_dma_chan_filter, dws);
  62         if (!dws->rxchan)
  63                 goto err_exit;
  64         rxs = &dw_dma->dmas_rx;
  65         rxs->hs_mode = LNW_DMA_HW_HS;
  66         rxs->cfg_mode = LNW_DMA_PER_TO_MEM;
  67         dws->rxchan->private = rxs;
  68
  69         /* 2. Init tx channel */
  70         dws->txchan = dma_request_channel(mask, mid_spi_dma_chan_filter, dws);
  71         if (!dws->txchan)
  72                 goto free_rxchan;
  73         txs = &dw_dma->dmas_tx;
  74         txs->hs_mode = LNW_DMA_HW_HS;
  75         txs->cfg_mode = LNW_DMA_MEM_TO_PER;
  76         dws->txchan->private = txs;
  77
  78         dws->dma_inited = 1;
  79         return 0;
  80
  81 free_rxchan:
  82         dma_release_channel(dws->rxchan);
  83 err_exit:
  84         return -1;
  85
  86 }
  87
  88 static void mid_spi_dma_exit(struct dw_spi *dws)
  89 {
  90         dma_release_channel(dws->txchan);
  91         dma_release_channel(dws->rxchan);
  92 }
  93
  94 /*
  95  * dws->dma_chan_done is cleared before the dma transfer starts,
  96  * callback for rx/tx channel will each increment it by 1.
  97  * Reaching 2 means the whole spi transaction is done.
  98  */
  99 static void dw_spi_dma_done(void *arg)
 100 {
 101         struct dw_spi *dws = arg;
 102
 103         if (++dws->dma_chan_done != 2)
 104                 return;
 105         dw_spi_xfer_done(dws);
 106 }
 107
 108 static int mid_spi_dma_transfer(struct dw_spi *dws, int cs_change)
 109 {
 110         struct dma_async_tx_descriptor *txdesc = NULL, *rxdesc = NULL;
 111         struct dma_chan *txchan, *rxchan;
 112         struct dma_slave_config txconf, rxconf;
 113         u16 dma_ctrl = 0;
 114
 115         /* 1. setup DMA related registers */
 116         if (cs_change) {
 117                 spi_enable_chip(dws, 0);
 118                 dw_writew(dws, dmardlr, 0xf);
 119                 dw_writew(dws, dmatdlr, 0x10);
 120                 if (dws->tx_dma)
 121                         dma_ctrl |= 0x2;
 122                 if (dws->rx_dma)
 123                         dma_ctrl |= 0x1;
 124                 dw_writew(dws, dmacr, dma_ctrl);
 125                 spi_enable_chip(dws, 1);
 126         }
 127
 128         dws->dma_chan_done = 0;
 129         txchan = dws->txchan;
 130         rxchan = dws->rxchan;
 131
 132         /* 2. Prepare the TX dma transfer */
 133         txconf.direction = DMA_TO_DEVICE;
 134         txconf.dst_addr = dws->dma_addr;
 135         txconf.dst_maxburst = LNW_DMA_MSIZE_16;
 136         txconf.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
 137         txconf.dst_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
 138
 139         txchan->device->device_control(txchan, DMA_SLAVE_CONFIG,
 140                                        (unsigned long) &txconf);
 141
 142         memset(&dws->tx_sgl, 0, sizeof(dws->tx_sgl));
 143         dws->tx_sgl.dma_address = dws->tx_dma;
 144         dws->tx_sgl.length = dws->len;
 145
 146         txdesc = txchan->device->device_prep_slave_sg(txchan,
 147                                 &dws->tx_sgl,
 148                                 1,
 149                                 DMA_TO_DEVICE,
 150                                 DMA_PREP_INTERRUPT | DMA_COMPL_SKIP_DEST_UNMAP);
 151         txdesc->callback = dw_spi_dma_done;
 152         txdesc->callback_param = dws;
 153
 154         /* 3. Prepare the RX dma transfer */
 155         rxconf.direction = DMA_FROM_DEVICE;
 156         rxconf.src_addr = dws->dma_addr;
 157         rxconf.src_maxburst = LNW_DMA_MSIZE_16;
 158         rxconf.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
 159         rxconf.src_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
 160
 161         rxchan->device->device_control(rxchan, DMA_SLAVE_CONFIG,
 162                                        (unsigned long) &rxconf);
 163
 164         memset(&dws->rx_sgl, 0, sizeof(dws->rx_sgl));
 165         dws->rx_sgl.dma_address = dws->rx_dma;
 166         dws->rx_sgl.length = dws->len;
 167
 168         rxdesc = rxchan->device->device_prep_slave_sg(rxchan,
 169                                 &dws->rx_sgl,
 170                                 1,
 171                                 DMA_FROM_DEVICE,
 172                                 DMA_PREP_INTERRUPT | DMA_COMPL_SKIP_DEST_UNMAP);
 173         rxdesc->callback = dw_spi_dma_done;
 174         rxdesc->callback_param = dws;
 175
 176         /* rx must be started before tx due to spi instinct */
 177         rxdesc->tx_submit(rxdesc);
 178         txdesc->tx_submit(txdesc);
 179         return 0;
 180 }
 181
 182 static struct dw_spi_dma_ops mid_dma_ops = {
 183         .dma_init       = mid_spi_dma_init,
 184         .dma_exit       = mid_spi_dma_exit,
 185         .dma_transfer   = mid_spi_dma_transfer,
 186 };
 187 #endif
 188
 189 /* Some specific info for SPI0 controller on Moorestown */
 190
 191 /* HW info for MRST CLk Control Unit, one 32b reg */
 192 #define MRST_SPI_CLK_BASE       100000000       /* 100m */
 193 #define MRST_CLK_SPI0_REG       0xff11d86c
 194 #define CLK_SPI_BDIV_OFFSET     0
 195 #define CLK_SPI_BDIV_MASK       0x00000007
 196 #define CLK_SPI_CDIV_OFFSET     9
 197 #define CLK_SPI_CDIV_MASK       0x00000e00
 198 #define CLK_SPI_DISABLE_OFFSET  8
 199
 200 int dw_spi_mid_init(struct dw_spi *dws)
 201 {
 202         u32 *clk_reg, clk_cdiv;
 203
 204         clk_reg = ioremap_nocache(MRST_CLK_SPI0_REG, 16);
 205         if (!clk_reg)
 206                 return -ENOMEM;
 207
 208         /* get SPI controller operating freq info */
 209         clk_cdiv  = (readl(clk_reg) & CLK_SPI_CDIV_MASK) >> CLK_SPI_CDIV_OFFSET;
 210         dws->max_freq = MRST_SPI_CLK_BASE / (clk_cdiv + 1);
 211         iounmap(clk_reg);
 212
 213         dws->num_cs = 16;
 214         dws->fifo_len = 40;     /* FIFO has 40 words buffer */
 215
 216 #ifdef CONFIG_SPI_DW_MID_DMA
 217         dws->dma_priv = kzalloc(sizeof(struct mid_dma), GFP_KERNEL);
 218         if (!dws->dma_priv)
 219                 return -ENOMEM;
 220         dws->dma_ops = &mid_dma_ops;
 221 #endif
 222         return 0;
 223 }