drivers/spi/spi-dw-mid.c

   1 /*
   2  * Special handling for DW core on Intel MID platform
   3  *
   4  * Copyright (c) 2009, 2014 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
  16 #include <linux/dma-mapping.h>
  17 #include <linux/dmaengine.h>
  18 #include <linux/interrupt.h>
  19 #include <linux/slab.h>
  20 #include <linux/spi/spi.h>
  21 #include <linux/types.h>
  22
  23 #include "spi-dw.h"
  24
  25 #ifdef CONFIG_SPI_DW_MID_DMA
  26 #include <linux/intel_mid_dma.h>
  27 #include <linux/pci.h>
  28
  29 struct mid_dma {
  30         struct intel_mid_dma_slave      dmas_tx;
  31         struct intel_mid_dma_slave      dmas_rx;
  32 };
  33
  34 static bool mid_spi_dma_chan_filter(struct dma_chan *chan, void *param)
  35 {
  36         struct dw_spi *dws = param;
  37
  38         return dws->dma_dev == chan->device->dev;
  39 }
  40
  41 static int mid_spi_dma_init(struct dw_spi *dws)
  42 {
  43         struct mid_dma *dw_dma = dws->dma_priv;
  44         struct pci_dev *dma_dev;
  45         struct intel_mid_dma_slave *rxs, *txs;
  46         dma_cap_mask_t mask;
  47
  48         /*
  49          * Get pci device for DMA controller, currently it could only
  50          * be the DMA controller of Medfield
  51          */
  52         dma_dev = pci_get_device(PCI_VENDOR_ID_INTEL, 0x0827, NULL);
  53         if (!dma_dev)
  54                 return -ENODEV;
  55
  56         dws->dma_dev = &dma_dev->dev;
  57
  58         dma_cap_zero(mask);
  59         dma_cap_set(DMA_SLAVE, mask);
  60
  61         /* 1. Init rx channel */
  62         dws->rxchan = dma_request_channel(mask, mid_spi_dma_chan_filter, dws);
  63         if (!dws->rxchan)
  64                 goto err_exit;
  65         rxs = &dw_dma->dmas_rx;
  66         rxs->hs_mode = LNW_DMA_HW_HS;
  67         rxs->cfg_mode = LNW_DMA_PER_TO_MEM;
  68         dws->rxchan->private = rxs;
  69
  70         /* 2. Init tx channel */
  71         dws->txchan = dma_request_channel(mask, mid_spi_dma_chan_filter, dws);
  72         if (!dws->txchan)
  73                 goto free_rxchan;
  74         txs = &dw_dma->dmas_tx;
  75         txs->hs_mode = LNW_DMA_HW_HS;
  76         txs->cfg_mode = LNW_DMA_MEM_TO_PER;
  77         dws->txchan->private = txs;
  78
  79         dws->dma_inited = 1;
  80         return 0;
  81
  82 free_rxchan:
  83         dma_release_channel(dws->rxchan);
  84 err_exit:
  85         return -EBUSY;
  86 }
  87
  88 static void mid_spi_dma_exit(struct dw_spi *dws)
  89 {
  90         if (!dws->dma_inited)
  91                 return;
  92         dma_release_channel(dws->txchan);
  93         dma_release_channel(dws->rxchan);
  94 }
  95
  96 /*
  97  * dws->dma_chan_done is cleared before the dma transfer starts,
  98  * callback for rx/tx channel will each increment it by 1.
  99  * Reaching 2 means the whole spi transaction is done.
 100  */
 101 static void dw_spi_dma_done(void *arg)
 102 {
 103         struct dw_spi *dws = arg;
 104
 105         if (++dws->dma_chan_done != 2)
 106                 return;
 107         dw_spi_xfer_done(dws);
 108 }
 109
 110 static int mid_spi_dma_transfer(struct dw_spi *dws, int cs_change)
 111 {
 112         struct dma_async_tx_descriptor *txdesc = NULL, *rxdesc = NULL;
 113         struct dma_chan *txchan, *rxchan;
 114         struct dma_slave_config txconf, rxconf;
 115         u16 dma_ctrl = 0;
 116
 117         /* 1. setup DMA related registers */
 118         if (cs_change) {
 119                 spi_enable_chip(dws, 0);
 120                 dw_writew(dws, DW_SPI_DMARDLR, 0xf);
 121                 dw_writew(dws, DW_SPI_DMATDLR, 0x10);
 122                 if (dws->tx_dma)
 123                         dma_ctrl |= 0x2;
 124                 if (dws->rx_dma)
 125                         dma_ctrl |= 0x1;
 126                 dw_writew(dws, DW_SPI_DMACR, dma_ctrl);
 127                 spi_enable_chip(dws, 1);
 128         }
 129
 130         dws->dma_chan_done = 0;
 131         txchan = dws->txchan;
 132         rxchan = dws->rxchan;
 133
 134         /* 2. Prepare the TX dma transfer */
 135         txconf.direction = DMA_MEM_TO_DEV;
 136         txconf.dst_addr = dws->dma_addr;
 137         txconf.dst_maxburst = LNW_DMA_MSIZE_16;
 138         txconf.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
 139         txconf.dst_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
 140         txconf.device_fc = false;
 141
 142         txchan->device->device_control(txchan, DMA_SLAVE_CONFIG,
 143                                        (unsigned long) &txconf);
 144
 145         memset(&dws->tx_sgl, 0, sizeof(dws->tx_sgl));
 146         dws->tx_sgl.dma_address = dws->tx_dma;
 147         dws->tx_sgl.length = dws->len;
 148
 149         txdesc = dmaengine_prep_slave_sg(txchan,
 150                                 &dws->tx_sgl,
 151                                 1,
 152                                 DMA_MEM_TO_DEV,
 153                                 DMA_PREP_INTERRUPT);
 154         txdesc->callback = dw_spi_dma_done;
 155         txdesc->callback_param = dws;
 156
 157         /* 3. Prepare the RX dma transfer */
 158         rxconf.direction = DMA_DEV_TO_MEM;
 159         rxconf.src_addr = dws->dma_addr;
 160         rxconf.src_maxburst = LNW_DMA_MSIZE_16;
 161         rxconf.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
 162         rxconf.src_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
 163         rxconf.device_fc = false;
 164
 165         rxchan->device->device_control(rxchan, DMA_SLAVE_CONFIG,
 166                                        (unsigned long) &rxconf);
 167
 168         memset(&dws->rx_sgl, 0, sizeof(dws->rx_sgl));
 169         dws->rx_sgl.dma_address = dws->rx_dma;
 170         dws->rx_sgl.length = dws->len;
 171
 172         rxdesc = dmaengine_prep_slave_sg(rxchan,
 173                                 &dws->rx_sgl,
 174                                 1,
 175                                 DMA_DEV_TO_MEM,
 176                                 DMA_PREP_INTERRUPT);
 177         rxdesc->callback = dw_spi_dma_done;
 178         rxdesc->callback_param = dws;
 179
 180         /* rx must be started before tx due to spi instinct */
 181         rxdesc->tx_submit(rxdesc);
 182         txdesc->tx_submit(txdesc);
 183         return 0;
 184 }
 185
 186 static struct dw_spi_dma_ops mid_dma_ops = {
 187         .dma_init       = mid_spi_dma_init,
 188         .dma_exit       = mid_spi_dma_exit,
 189         .dma_transfer   = mid_spi_dma_transfer,
 190 };
 191 #endif
 192
 193 /* Some specific info for SPI0 controller on Intel MID */
 194
 195 /* HW info for MRST CLk Control Unit, one 32b reg */
 196 #define MRST_SPI_CLK_BASE       100000000       /* 100m */
 197 #define MRST_CLK_SPI0_REG       0xff11d86c
 198 #define CLK_SPI_BDIV_OFFSET     0
 199 #define CLK_SPI_BDIV_MASK       0x00000007
 200 #define CLK_SPI_CDIV_OFFSET     9
 201 #define CLK_SPI_CDIV_MASK       0x00000e00
 202 #define CLK_SPI_DISABLE_OFFSET  8
 203
 204 int dw_spi_mid_init(struct dw_spi *dws)
 205 {
 206         void __iomem *clk_reg;
 207         u32 clk_cdiv;
 208
 209         clk_reg = ioremap_nocache(MRST_CLK_SPI0_REG, 16);
 210         if (!clk_reg)
 211                 return -ENOMEM;
 212
 213         /* get SPI controller operating freq info */
 214         clk_cdiv  = (readl(clk_reg) & CLK_SPI_CDIV_MASK) >> CLK_SPI_CDIV_OFFSET;
 215         dws->max_freq = MRST_SPI_CLK_BASE / (clk_cdiv + 1);
 216         iounmap(clk_reg);
 217
 218         dws->num_cs = 16;
 219         dws->fifo_len = 40;     /* FIFO has 40 words buffer */
 220
 221 #ifdef CONFIG_SPI_DW_MID_DMA
 222         dws->dma_priv = kzalloc(sizeof(struct mid_dma), GFP_KERNEL);
 223         if (!dws->dma_priv)
 224                 return -ENOMEM;
 225         dws->dma_ops = &mid_dma_ops;
 226 #endif
 227         return 0;
 228 }