diff options
Diffstat (limited to 'drivers/spi/dw_spi_mid.c')
| -rw-r--r-- | drivers/spi/dw_spi_mid.c | 223 |
1 files changed, 223 insertions, 0 deletions
diff --git a/drivers/spi/dw_spi_mid.c b/drivers/spi/dw_spi_mid.c new file mode 100644 index 000000000000..c91c966e0717 --- /dev/null +++ b/drivers/spi/dw_spi_mid.c @@ -0,0 +1,223 @@ +/* + * dw_spi_mid.c - special handling for DW core on Intel MID platform + * + * Copyright (c) 2009, Intel Corporation. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, + * Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA. + */ + +#include <linux/dma-mapping.h> +#include <linux/dmaengine.h> +#include <linux/interrupt.h> +#include <linux/slab.h> +#include <linux/spi/spi.h> +#include <linux/spi/dw_spi.h> + +#ifdef CONFIG_SPI_DW_MID_DMA +#include <linux/intel_mid_dma.h> +#include <linux/pci.h> + +struct mid_dma { + struct intel_mid_dma_slave dmas_tx; + struct intel_mid_dma_slave dmas_rx; +}; + +static bool mid_spi_dma_chan_filter(struct dma_chan *chan, void *param) +{ + struct dw_spi *dws = param; + + return dws->dmac && (&dws->dmac->dev == chan->device->dev); +} + +static int mid_spi_dma_init(struct dw_spi *dws) +{ + struct mid_dma *dw_dma = dws->dma_priv; + struct intel_mid_dma_slave *rxs, *txs; + dma_cap_mask_t mask; + + /* + * Get pci device for DMA controller, currently it could only + * be the DMA controller of either Moorestown or Medfield + */ + dws->dmac = pci_get_device(PCI_VENDOR_ID_INTEL, 0x0813, NULL); + if (!dws->dmac) + dws->dmac = pci_get_device(PCI_VENDOR_ID_INTEL, 0x0827, NULL); + + dma_cap_zero(mask); + dma_cap_set(DMA_SLAVE, mask); + + /* 1. Init rx channel */ + dws->rxchan = dma_request_channel(mask, mid_spi_dma_chan_filter, dws); + if (!dws->rxchan) + goto err_exit; + rxs = &dw_dma->dmas_rx; + rxs->hs_mode = LNW_DMA_HW_HS; + rxs->cfg_mode = LNW_DMA_PER_TO_MEM; + dws->rxchan->private = rxs; + + /* 2. Init tx channel */ + dws->txchan = dma_request_channel(mask, mid_spi_dma_chan_filter, dws); + if (!dws->txchan) + goto free_rxchan; + txs = &dw_dma->dmas_tx; + txs->hs_mode = LNW_DMA_HW_HS; + txs->cfg_mode = LNW_DMA_MEM_TO_PER; + dws->txchan->private = txs; + + dws->dma_inited = 1; + return 0; + +free_rxchan: + dma_release_channel(dws->rxchan); +err_exit: + return -1; + +} + +static void mid_spi_dma_exit(struct dw_spi *dws) +{ + dma_release_channel(dws->txchan); + dma_release_channel(dws->rxchan); +} + +/* + * dws->dma_chan_done is cleared before the dma transfer starts, + * callback for rx/tx channel will each increment it by 1. + * Reaching 2 means the whole spi transaction is done. + */ +static void dw_spi_dma_done(void *arg) +{ + struct dw_spi *dws = arg; + + if (++dws->dma_chan_done != 2) + return; + dw_spi_xfer_done(dws); +} + +static int mid_spi_dma_transfer(struct dw_spi *dws, int cs_change) +{ + struct dma_async_tx_descriptor *txdesc = NULL, *rxdesc = NULL; + struct dma_chan *txchan, *rxchan; + struct dma_slave_config txconf, rxconf; + u16 dma_ctrl = 0; + + /* 1. setup DMA related registers */ + if (cs_change) { + spi_enable_chip(dws, 0); + dw_writew(dws, dmardlr, 0xf); + dw_writew(dws, dmatdlr, 0x10); + if (dws->tx_dma) + dma_ctrl |= 0x2; + if (dws->rx_dma) + dma_ctrl |= 0x1; + dw_writew(dws, dmacr, dma_ctrl); + spi_enable_chip(dws, 1); + } + + dws->dma_chan_done = 0; + txchan = dws->txchan; + rxchan = dws->rxchan; + + /* 2. Prepare the TX dma transfer */ + txconf.direction = DMA_TO_DEVICE; + txconf.dst_addr = dws->dma_addr; + txconf.dst_maxburst = LNW_DMA_MSIZE_16; + txconf.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES; + txconf.dst_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES; + + txchan->device->device_control(txchan, DMA_SLAVE_CONFIG, + (unsigned long) &txconf); + + memset(&dws->tx_sgl, 0, sizeof(dws->tx_sgl)); + dws->tx_sgl.dma_address = dws->tx_dma; + dws->tx_sgl.length = dws->len; + + txdesc = txchan->device->device_prep_slave_sg(txchan, + &dws->tx_sgl, + 1, + DMA_TO_DEVICE, + DMA_PREP_INTERRUPT | DMA_COMPL_SKIP_DEST_UNMAP); + txdesc->callback = dw_spi_dma_done; + txdesc->callback_param = dws; + + /* 3. Prepare the RX dma transfer */ + rxconf.direction = DMA_FROM_DEVICE; + rxconf.src_addr = dws->dma_addr; + rxconf.src_maxburst = LNW_DMA_MSIZE_16; + rxconf.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES; + rxconf.src_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES; + + rxchan->device->device_control(rxchan, DMA_SLAVE_CONFIG, + (unsigned long) &rxconf); + + memset(&dws->rx_sgl, 0, sizeof(dws->rx_sgl)); + dws->rx_sgl.dma_address = dws->rx_dma; + dws->rx_sgl.length = dws->len; + + rxdesc = rxchan->device->device_prep_slave_sg(rxchan, + &dws->rx_sgl, + 1, + DMA_FROM_DEVICE, + DMA_PREP_INTERRUPT | DMA_COMPL_SKIP_DEST_UNMAP); + rxdesc->callback = dw_spi_dma_done; + rxdesc->callback_param = dws; + + /* rx must be started before tx due to spi instinct */ + rxdesc->tx_submit(rxdesc); + txdesc->tx_submit(txdesc); + return 0; +} + +static struct dw_spi_dma_ops mid_dma_ops = { + .dma_init = mid_spi_dma_init, + .dma_exit = mid_spi_dma_exit, + .dma_transfer = mid_spi_dma_transfer, +}; +#endif + +/* Some specific info for SPI0 controller on Moorestown */ + +/* HW info for MRST CLk Control Unit, one 32b reg */ +#define MRST_SPI_CLK_BASE 100000000 /* 100m */ +#define MRST_CLK_SPI0_REG 0xff11d86c +#define CLK_SPI_BDIV_OFFSET 0 +#define CLK_SPI_BDIV_MASK 0x00000007 +#define CLK_SPI_CDIV_OFFSET 9 +#define CLK_SPI_CDIV_MASK 0x00000e00 +#define CLK_SPI_DISABLE_OFFSET 8 + +int dw_spi_mid_init(struct dw_spi *dws) +{ + u32 *clk_reg, clk_cdiv; + + clk_reg = ioremap_nocache(MRST_CLK_SPI0_REG, 16); + if (!clk_reg) + return -ENOMEM; + + /* get SPI controller operating freq info */ + clk_cdiv = (readl(clk_reg) & CLK_SPI_CDIV_MASK) >> CLK_SPI_CDIV_OFFSET; + dws->max_freq = MRST_SPI_CLK_BASE / (clk_cdiv + 1); + iounmap(clk_reg); + + dws->num_cs = 16; + dws->fifo_len = 40; /* FIFO has 40 words buffer */ + +#ifdef CONFIG_SPI_DW_MID_DMA + dws->dma_priv = kzalloc(sizeof(struct mid_dma), GFP_KERNEL); + if (!dws->dma_priv) + return -ENOMEM; + dws->dma_ops = &mid_dma_ops; +#endif + return 0; +} |