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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: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: Bryan O'Donoghue <pure.logic@nexus-software.ie>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Andy Shevchenko 2016-08-17 19:20:30 +03:00 committed by Greg Kroah-Hartman
parent 60a9244a5d
commit fecdef932b
1 changed files with 75 additions and 3 deletions
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78
drivers/tty/serial/8250/8250_lpss.c
View File

@ -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 }