drivers/spi/spi-dw-mid.c - linux - Git at Google

 /*
  * 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;
 }
	/*
	* 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;
	}