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linux-next/drivers/spi/spi-dw-mid.c
Andy Shevchenko 30c8eb52cc spi: dw-mid: split rx and tx callbacks when DMA
Currently driver wouldn't work properly if user asked for simplex transfer. The
patch separates DMA rx and tx callbacks and finishes transfer correctly in any
case.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2014-10-28 22:40:38 +00:00

284 lines
6.7 KiB
C

/*
* Special handling for DW core on Intel MID platform
*
* Copyright (c) 2009, 2014 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.
*/
#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>
#include <linux/interrupt.h>
#include <linux/slab.h>
#include <linux/spi/spi.h>
#include <linux/types.h>
#include "spi-dw.h"
#ifdef CONFIG_SPI_DW_MID_DMA
#include <linux/intel_mid_dma.h>
#include <linux/pci.h>
#define RX_BUSY 0
#define TX_BUSY 1
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->dma_dev == chan->device->dev;
}
static int mid_spi_dma_init(struct dw_spi *dws)
{
struct mid_dma *dw_dma = dws->dma_priv;
struct pci_dev *dma_dev;
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 Medfield
*/
dma_dev = pci_get_device(PCI_VENDOR_ID_INTEL, 0x0827, NULL);
if (!dma_dev)
return -ENODEV;
dws->dma_dev = &dma_dev->dev;
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 -EBUSY;
}
static void mid_spi_dma_exit(struct dw_spi *dws)
{
if (!dws->dma_inited)
return;
dmaengine_terminate_all(dws->txchan);
dma_release_channel(dws->txchan);
dmaengine_terminate_all(dws->rxchan);
dma_release_channel(dws->rxchan);
}
/*
* dws->dma_chan_busy is set before the dma transfer starts, callback for tx
* channel will clear a corresponding bit.
*/
static void dw_spi_dma_tx_done(void *arg)
{
struct dw_spi *dws = arg;
if (test_and_clear_bit(TX_BUSY, &dws->dma_chan_busy) & BIT(RX_BUSY))
return;
dw_spi_xfer_done(dws);
}
static struct dma_async_tx_descriptor *dw_spi_dma_prepare_tx(struct dw_spi *dws)
{
struct dma_slave_config txconf;
struct dma_async_tx_descriptor *txdesc;
if (!dws->tx_dma)
return NULL;
txconf.direction = DMA_MEM_TO_DEV;
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 = dws->dma_width;
txconf.device_fc = false;
dmaengine_slave_config(dws->txchan, &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 = dmaengine_prep_slave_sg(dws->txchan,
&dws->tx_sgl,
1,
DMA_MEM_TO_DEV,
DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
txdesc->callback = dw_spi_dma_tx_done;
txdesc->callback_param = dws;
return txdesc;
}
/*
* dws->dma_chan_busy is set before the dma transfer starts, callback for rx
* channel will clear a corresponding bit.
*/
static void dw_spi_dma_rx_done(void *arg)
{
struct dw_spi *dws = arg;
if (test_and_clear_bit(RX_BUSY, &dws->dma_chan_busy) & BIT(TX_BUSY))
return;
dw_spi_xfer_done(dws);
}
static struct dma_async_tx_descriptor *dw_spi_dma_prepare_rx(struct dw_spi *dws)
{
struct dma_slave_config rxconf;
struct dma_async_tx_descriptor *rxdesc;
if (!dws->rx_dma)
return NULL;
rxconf.direction = DMA_DEV_TO_MEM;
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 = dws->dma_width;
rxconf.device_fc = false;
dmaengine_slave_config(dws->rxchan, &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 = dmaengine_prep_slave_sg(dws->rxchan,
&dws->rx_sgl,
1,
DMA_DEV_TO_MEM,
DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
rxdesc->callback = dw_spi_dma_rx_done;
rxdesc->callback_param = dws;
return rxdesc;
}
static void dw_spi_dma_setup(struct dw_spi *dws)
{
u16 dma_ctrl = 0;
spi_enable_chip(dws, 0);
dw_writew(dws, DW_SPI_DMARDLR, 0xf);
dw_writew(dws, DW_SPI_DMATDLR, 0x10);
if (dws->tx_dma)
dma_ctrl |= SPI_DMA_TDMAE;
if (dws->rx_dma)
dma_ctrl |= SPI_DMA_RDMAE;
dw_writew(dws, DW_SPI_DMACR, dma_ctrl);
spi_enable_chip(dws, 1);
}
static int mid_spi_dma_transfer(struct dw_spi *dws, int cs_change)
{
struct dma_async_tx_descriptor *txdesc, *rxdesc;
/* 1. setup DMA related registers */
if (cs_change)
dw_spi_dma_setup(dws);
/* 2. Prepare the TX dma transfer */
txdesc = dw_spi_dma_prepare_tx(dws);
/* 3. Prepare the RX dma transfer */
rxdesc = dw_spi_dma_prepare_rx(dws);
/* rx must be started before tx due to spi instinct */
if (rxdesc) {
set_bit(RX_BUSY, &dws->dma_chan_busy);
dmaengine_submit(rxdesc);
dma_async_issue_pending(dws->rxchan);
}
if (txdesc) {
set_bit(TX_BUSY, &dws->dma_chan_busy);
dmaengine_submit(txdesc);
dma_async_issue_pending(dws->txchan);
}
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 Intel MID */
/* 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)
{
void __iomem *clk_reg;
u32 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;
}