[PATCH v7 11/11] serial: 8250_lpss: enable DMA on Intel Quark UART

Andy Shevchenko
2016-06-17T12:42:42Z

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

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
drivers/tty/serial/8250/8250_lpss.c | 84 +++++++++++++++++++++++++++++++++++--
1 file changed, 80 insertions(+), 4 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_lpss.c b/drivers/tty/serial/8250/8250_lpss.c
index 5ac291c..1b464cd 100644
--- a/drivers/tty/serial/8250/8250_lpss.c
+++ b/drivers/tty/serial/8250/8250_lpss.c
@@ -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 +153,66 @@ 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 int 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 0;
+
+ /* 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;
+ return 0;
+}
+
+static void qrk_serial_exit_dma(struct lpss8250 *lpss)
+{
+ qrk_serial_exit_dma(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 int qrk_serial_setup_dma(struct lpss8250 *lpss, struct uart_port *port)
+{
+ return 0;
+}
+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);
@@ -159,7 +221,12 @@ static int qrk_serial_setup(struct lpss8250 *lpss, struct uart_port *port)

port->irq = pdev->irq;

- return 0;
+ return qrk_serial_setup_dma(lpss, port);
+}
+
+static void qrk_serial_exit(struct lpss8250 *lpss)
+{
+ qrk_serial_exit_dma(lpss);
}

static bool lpss8250_dma_filter(struct dma_chan *chan, void *param)
@@ -244,22 +311,30 @@ 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);
}

@@ -273,6 +348,7 @@ 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 }
--
2.8.1