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Commit fecdef93 authored by Andy Shevchenko's avatar Andy Shevchenko Committed by Greg Kroah-Hartman
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serial: 8250_lpss: enable DMA on Intel Quark UART 



DMA on Intel Quark SoC is a part of UART IP block. Enable it.

Signed-off-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: default avatarBryan O'Donoghue <pure.logic@nexus-software.ie>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 60a9244a

drivers/tty/serial/8250/8250_lpss.c

+75 −3
Original line number Diff line number Diff line
@@ -15,7 +15,7 @@ 
#include <linux/rational.h>



#include <linux/dmaengine.h>

#include <linux/platform_data/dma-dw.h>

#include <linux/dma/dw.h>



#include "8250.h"
@@ -47,6 +47,7 @@ struct lpss8250_board { 
	unsigned long freq;

	unsigned int base_baud;

	int (*setup)(struct lpss8250 *, struct uart_port *p);

	void (*exit)(struct lpss8250 *);

};



struct lpss8250 {
@@ -55,6 +56,7 @@ struct lpss8250 { 


	/* DMA parameters */

	struct uart_8250_dma dma;

	struct dw_dma_chip dma_chip;

	struct dw_dma_slave dma_param;

	u8 dma_maxburst;

};
@@ -151,6 +153,61 @@ static int byt_serial_setup(struct lpss8250 *lpss, struct uart_port *port) 
	return 0;

}



#ifdef CONFIG_SERIAL_8250_DMA

static const struct dw_dma_platform_data qrk_serial_dma_pdata = {

	.nr_channels = 2,

	.is_private = true,

	.is_nollp = true,

	.chan_allocation_order = CHAN_ALLOCATION_ASCENDING,

	.chan_priority = CHAN_PRIORITY_ASCENDING,

	.block_size = 4095,

	.nr_masters = 1,

	.data_width = {4},

};



static void qrk_serial_setup_dma(struct lpss8250 *lpss, struct uart_port *port)

{

	struct uart_8250_dma *dma = &lpss->dma;

	struct dw_dma_chip *chip = &lpss->dma_chip;

	struct dw_dma_slave *param = &lpss->dma_param;

	struct pci_dev *pdev = to_pci_dev(port->dev);

	int ret;



	chip->dev = &pdev->dev;

	chip->irq = pdev->irq;

	chip->regs = pci_ioremap_bar(pdev, 1);

	chip->pdata = &qrk_serial_dma_pdata;



	/* Falling back to PIO mode if DMA probing fails */

	ret = dw_dma_probe(chip);

	if (ret)

		return;



	/* Special DMA address for UART */

	dma->rx_dma_addr = 0xfffff000;

	dma->tx_dma_addr = 0xfffff000;



	param->dma_dev = &pdev->dev;

	param->src_id = 0;

	param->dst_id = 1;

	param->hs_polarity = true;



	lpss->dma_maxburst = 8;

}



static void qrk_serial_exit_dma(struct lpss8250 *lpss)

{

	struct dw_dma_slave *param = &lpss->dma_param;



	if (!param->dma_dev)

		return;

	dw_dma_remove(&lpss->dma_chip);

}

#else	/* CONFIG_SERIAL_8250_DMA */

static void qrk_serial_setup_dma(struct lpss8250 *lpss, struct uart_port *port) {}

static void qrk_serial_exit_dma(struct lpss8250 *lpss) {}

#endif	/* !CONFIG_SERIAL_8250_DMA */



static int qrk_serial_setup(struct lpss8250 *lpss, struct uart_port *port)

{

	struct pci_dev *pdev = to_pci_dev(port->dev);
@@ -162,9 +219,15 @@ static int qrk_serial_setup(struct lpss8250 *lpss, struct uart_port *port) 


	port->irq = pci_irq_vector(pdev, 0);



	qrk_serial_setup_dma(lpss, port);

	return 0;

}



static void qrk_serial_exit(struct lpss8250 *lpss)

{

	qrk_serial_exit_dma(lpss);

}



static bool lpss8250_dma_filter(struct dma_chan *chan, void *param)

{

	struct dw_dma_slave *dws = param;
@@ -247,22 +310,30 @@ static int lpss8250_probe(struct pci_dev *pdev, const struct pci_device_id *id) 


	ret = lpss8250_dma_setup(lpss, &uart);

	if (ret)

		return ret;

		goto err_exit;



	ret = serial8250_register_8250_port(&uart);

	if (ret < 0)

		return ret;

		goto err_exit;



	lpss->line = ret;



	pci_set_drvdata(pdev, lpss);

	return 0;



err_exit:

	if (lpss->board->exit)

		lpss->board->exit(lpss);

	return ret;

}



static void lpss8250_remove(struct pci_dev *pdev)

{

	struct lpss8250 *lpss = pci_get_drvdata(pdev);



	if (lpss->board->exit)

		lpss->board->exit(lpss);



	serial8250_unregister_port(lpss->line);

}
@@ -276,6 +347,7 @@ static const struct lpss8250_board qrk_board = { 
	.freq = 44236800,

	.base_baud = 2764800,

	.setup = qrk_serial_setup,

	.exit = qrk_serial_exit,

};



#define LPSS_DEVICE(id, board) { PCI_VDEVICE(INTEL, id), (kernel_ulong_t)&board }