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/pci.h>
  27 #include <linux/platform_data/dma-dw.h>
  28
  29 #define RX_BUSY         0
  30 #define TX_BUSY         1
  31
  32 static struct dw_dma_slave mid_dma_tx = { .dst_id = 1 };
  33 static struct dw_dma_slave mid_dma_rx = { .src_id = 0 };
  34
  35 static bool mid_spi_dma_chan_filter(struct dma_chan *chan, void *param)
  36 {
  37         struct dw_dma_slave *s = param;
  38
  39         if (s->dma_dev != chan->device->dev)
  40                 return false;
  41
  42         chan->private = s;
  43         return true;
  44 }
  45
  46 static int mid_spi_dma_init(struct dw_spi *dws)
  47 {
  48         struct pci_dev *dma_dev;
  49         struct dw_dma_slave *tx = dws->dma_tx;
  50         struct dw_dma_slave *rx = dws->dma_rx;
  51         dma_cap_mask_t mask;
  52
  53         /*
  54          * Get pci device for DMA controller, currently it could only
  55          * be the DMA controller of Medfield
  56          */
  57         dma_dev = pci_get_device(PCI_VENDOR_ID_INTEL, 0x0827, NULL);
  58         if (!dma_dev)
  59                 return -ENODEV;
  60
  61         dma_cap_zero(mask);
  62         dma_cap_set(DMA_SLAVE, mask);
  63
  64         /* 1. Init rx channel */
  65         rx->dma_dev = &dma_dev->dev;
  66         dws->rxchan = dma_request_channel(mask, mid_spi_dma_chan_filter, rx);
  67         if (!dws->rxchan)
  68                 goto err_exit;
  69         dws->master->dma_rx = dws->rxchan;
  70
  71         /* 2. Init tx channel */
  72         tx->dma_dev = &dma_dev->dev;
  73         dws->txchan = dma_request_channel(mask, mid_spi_dma_chan_filter, tx);
  74         if (!dws->txchan)
  75                 goto free_rxchan;
  76         dws->master->dma_tx = dws->txchan;
  77
  78         dws->dma_inited = 1;
  79         return 0;
  80
  81 free_rxchan:
  82         dma_release_channel(dws->rxchan);
  83 err_exit:
  84         return -EBUSY;
  85 }
  86
  87 static void mid_spi_dma_exit(struct dw_spi *dws)
  88 {
  89         if (!dws->dma_inited)
  90                 return;
  91
  92         dmaengine_terminate_all(dws->txchan);
  93         dma_release_channel(dws->txchan);
  94
  95         dmaengine_terminate_all(dws->rxchan);
  96         dma_release_channel(dws->rxchan);
  97 }
  98
  99 static irqreturn_t dma_transfer(struct dw_spi *dws)
 100 {
 101         u16 irq_status = dw_readl(dws, DW_SPI_ISR);
 102
 103         if (!irq_status)
 104                 return IRQ_NONE;
 105
 106         dw_readl(dws, DW_SPI_ICR);
 107         spi_reset_chip(dws);
 108
 109         dev_err(&dws->master->dev, "%s: FIFO overrun/underrun\n", __func__);
 110         dws->master->cur_msg->status = -EIO;
 111         spi_finalize_current_transfer(dws->master);
 112         return IRQ_HANDLED;
 113 }
 114
 115 static bool mid_spi_can_dma(struct spi_master *master, struct spi_device *spi,
 116                 struct spi_transfer *xfer)
 117 {
 118         struct dw_spi *dws = spi_master_get_devdata(master);
 119
 120         if (!dws->dma_inited)
 121                 return false;
 122
 123         return xfer->len > dws->fifo_len;
 124 }
 125
 126 static enum dma_slave_buswidth convert_dma_width(u32 dma_width) {
 127         if (dma_width == 1)
 128                 return DMA_SLAVE_BUSWIDTH_1_BYTE;
 129         else if (dma_width == 2)
 130                 return DMA_SLAVE_BUSWIDTH_2_BYTES;
 131
 132         return DMA_SLAVE_BUSWIDTH_UNDEFINED;
 133 }
 134
 135 /*
 136  * dws->dma_chan_busy is set before the dma transfer starts, callback for tx
 137  * channel will clear a corresponding bit.
 138  */
 139 static void dw_spi_dma_tx_done(void *arg)
 140 {
 141         struct dw_spi *dws = arg;
 142
 143         clear_bit(TX_BUSY, &dws->dma_chan_busy);
 144         if (test_bit(RX_BUSY, &dws->dma_chan_busy))
 145                 return;
 146         spi_finalize_current_transfer(dws->master);
 147 }
 148
 149 static struct dma_async_tx_descriptor *dw_spi_dma_prepare_tx(struct dw_spi *dws,
 150                 struct spi_transfer *xfer)
 151 {
 152         struct dma_slave_config txconf;
 153         struct dma_async_tx_descriptor *txdesc;
 154
 155         if (!xfer->tx_buf)
 156                 return NULL;
 157
 158         txconf.direction = DMA_MEM_TO_DEV;
 159         txconf.dst_addr = dws->dma_addr;
 160         txconf.dst_maxburst = 16;
 161         txconf.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
 162         txconf.dst_addr_width = convert_dma_width(dws->dma_width);
 163         txconf.device_fc = false;
 164
 165         dmaengine_slave_config(dws->txchan, &txconf);
 166
 167         txdesc = dmaengine_prep_slave_sg(dws->txchan,
 168                                 xfer->tx_sg.sgl,
 169                                 xfer->tx_sg.nents,
 170                                 DMA_MEM_TO_DEV,
 171                                 DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
 172         if (!txdesc)
 173                 return NULL;
 174
 175         txdesc->callback = dw_spi_dma_tx_done;
 176         txdesc->callback_param = dws;
 177
 178         return txdesc;
 179 }
 180
 181 /*
 182  * dws->dma_chan_busy is set before the dma transfer starts, callback for rx
 183  * channel will clear a corresponding bit.
 184  */
 185 static void dw_spi_dma_rx_done(void *arg)
 186 {
 187         struct dw_spi *dws = arg;
 188
 189         clear_bit(RX_BUSY, &dws->dma_chan_busy);
 190         if (test_bit(TX_BUSY, &dws->dma_chan_busy))
 191                 return;
 192         spi_finalize_current_transfer(dws->master);
 193 }
 194
 195 static struct dma_async_tx_descriptor *dw_spi_dma_prepare_rx(struct dw_spi *dws,
 196                 struct spi_transfer *xfer)
 197 {
 198         struct dma_slave_config rxconf;
 199         struct dma_async_tx_descriptor *rxdesc;
 200
 201         if (!xfer->rx_buf)
 202                 return NULL;
 203
 204         rxconf.direction = DMA_DEV_TO_MEM;
 205         rxconf.src_addr = dws->dma_addr;
 206         rxconf.src_maxburst = 16;
 207         rxconf.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
 208         rxconf.src_addr_width = convert_dma_width(dws->dma_width);
 209         rxconf.device_fc = false;
 210
 211         dmaengine_slave_config(dws->rxchan, &rxconf);
 212
 213         rxdesc = dmaengine_prep_slave_sg(dws->rxchan,
 214                                 xfer->rx_sg.sgl,
 215                                 xfer->rx_sg.nents,
 216                                 DMA_DEV_TO_MEM,
 217                                 DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
 218         if (!rxdesc)
 219                 return NULL;
 220
 221         rxdesc->callback = dw_spi_dma_rx_done;
 222         rxdesc->callback_param = dws;
 223
 224         return rxdesc;
 225 }
 226
 227 static int mid_spi_dma_setup(struct dw_spi *dws, struct spi_transfer *xfer)
 228 {
 229         u16 dma_ctrl = 0;
 230
 231         dw_writel(dws, DW_SPI_DMARDLR, 0xf);
 232         dw_writel(dws, DW_SPI_DMATDLR, 0x10);
 233
 234         if (xfer->tx_buf)
 235                 dma_ctrl |= SPI_DMA_TDMAE;
 236         if (xfer->rx_buf)
 237                 dma_ctrl |= SPI_DMA_RDMAE;
 238         dw_writel(dws, DW_SPI_DMACR, dma_ctrl);
 239
 240         /* Set the interrupt mask */
 241         spi_umask_intr(dws, SPI_INT_TXOI | SPI_INT_RXUI | SPI_INT_RXOI);
 242
 243         dws->transfer_handler = dma_transfer;
 244
 245         return 0;
 246 }
 247
 248 static int mid_spi_dma_transfer(struct dw_spi *dws, struct spi_transfer *xfer)
 249 {
 250         struct dma_async_tx_descriptor *txdesc, *rxdesc;
 251
 252         /* Prepare the TX dma transfer */
 253         txdesc = dw_spi_dma_prepare_tx(dws, xfer);
 254
 255         /* Prepare the RX dma transfer */
 256         rxdesc = dw_spi_dma_prepare_rx(dws, xfer);
 257
 258         /* rx must be started before tx due to spi instinct */
 259         if (rxdesc) {
 260                 set_bit(RX_BUSY, &dws->dma_chan_busy);
 261                 dmaengine_submit(rxdesc);
 262                 dma_async_issue_pending(dws->rxchan);
 263         }
 264
 265         if (txdesc) {
 266                 set_bit(TX_BUSY, &dws->dma_chan_busy);
 267                 dmaengine_submit(txdesc);
 268                 dma_async_issue_pending(dws->txchan);
 269         }
 270
 271         return 0;
 272 }
 273
 274 static void mid_spi_dma_stop(struct dw_spi *dws)
 275 {
 276         if (test_bit(TX_BUSY, &dws->dma_chan_busy)) {
 277                 dmaengine_terminate_all(dws->txchan);
 278                 clear_bit(TX_BUSY, &dws->dma_chan_busy);
 279         }
 280         if (test_bit(RX_BUSY, &dws->dma_chan_busy)) {
 281                 dmaengine_terminate_all(dws->rxchan);
 282                 clear_bit(RX_BUSY, &dws->dma_chan_busy);
 283         }
 284 }
 285
 286 static struct dw_spi_dma_ops mid_dma_ops = {
 287         .dma_init       = mid_spi_dma_init,
 288         .dma_exit       = mid_spi_dma_exit,
 289         .dma_setup      = mid_spi_dma_setup,
 290         .can_dma        = mid_spi_can_dma,
 291         .dma_transfer   = mid_spi_dma_transfer,
 292         .dma_stop       = mid_spi_dma_stop,
 293 };
 294 #endif
 295
 296 /* Some specific info for SPI0 controller on Intel MID */
 297
 298 /* HW info for MRST Clk Control Unit, 32b reg per controller */
 299 #define MRST_SPI_CLK_BASE       100000000       /* 100m */
 300 #define MRST_CLK_SPI_REG        0xff11d86c
 301 #define CLK_SPI_BDIV_OFFSET     0
 302 #define CLK_SPI_BDIV_MASK       0x00000007
 303 #define CLK_SPI_CDIV_OFFSET     9
 304 #define CLK_SPI_CDIV_MASK       0x00000e00
 305 #define CLK_SPI_DISABLE_OFFSET  8
 306
 307 int dw_spi_mid_init(struct dw_spi *dws)
 308 {
 309         void __iomem *clk_reg;
 310         u32 clk_cdiv;
 311
 312         clk_reg = ioremap_nocache(MRST_CLK_SPI_REG, 16);
 313         if (!clk_reg)
 314                 return -ENOMEM;
 315
 316         /* Get SPI controller operating freq info */
 317         clk_cdiv = readl(clk_reg + dws->bus_num * sizeof(u32));
 318         clk_cdiv &= CLK_SPI_CDIV_MASK;
 319         clk_cdiv >>= CLK_SPI_CDIV_OFFSET;
 320         dws->max_freq = MRST_SPI_CLK_BASE / (clk_cdiv + 1);
 321
 322         iounmap(clk_reg);
 323
 324 #ifdef CONFIG_SPI_DW_MID_DMA
 325         dws->dma_tx = &mid_dma_tx;
 326         dws->dma_rx = &mid_dma_rx;
 327         dws->dma_ops = &mid_dma_ops;
 328 #endif
 329         return 0;
 330 }