Re: [PATCH 5/5] serial: 8250_mid: add support for DMA engine handling from UART MMIO

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On Mon, 2015-10-05 at 16:41 +0300, Heikki Krogerus wrote:
> The platforms that have this UART, but that don't have
> separate PCI device for the DMA Engine, need to create the
> HSU DMA Engine device separately.


One comment below.

> 
> Signed-off-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> ---
>  drivers/tty/serial/8250/8250_mid.c | 67 
> ++++++++++++++++++++++++++++++++++++--
>  drivers/tty/serial/8250/8250_pci.c |  1 +
>  2 files changed, 66 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/tty/serial/8250/8250_mid.c 
> b/drivers/tty/serial/8250/8250_mid.c
> index 61f604c..06eb10c 100644
> --- a/drivers/tty/serial/8250/8250_mid.c
> +++ b/drivers/tty/serial/8250/8250_mid.c
> @@ -21,6 +21,7 @@
>  #define PCI_DEVICE_ID_INTEL_PNW_UART2	0x081c
>  #define PCI_DEVICE_ID_INTEL_PNW_UART3	0x081d
>  #define PCI_DEVICE_ID_INTEL_TNG_UART	0x1191
> +#define PCI_DEVICE_ID_INTEL_DNV_UART	0x19d8
>  
>  /* Intel MID Specific registers */
>  #define INTEL_MID_UART_PS		0x30
> @@ -33,6 +34,7 @@ struct mid8250_board {
>  	unsigned long freq;
>  	unsigned int base_baud;
>  	int (*setup)(struct mid8250 *, struct uart_port *p);
> +	void (*exit)(struct mid8250 *);
>  };
>  
>  struct mid8250 {
> @@ -41,6 +43,7 @@ struct mid8250 {
>  	struct pci_dev *dma_dev;
>  	struct uart_8250_dma dma;
>  	struct mid8250_board *board;
> +	struct hsu_dma_chip dma_chip;
>  };
>  
>  /*******************************************************************
> **********/
> @@ -82,6 +85,51 @@ static int tng_setup(struct mid8250 *mid, struct 
> uart_port *p)
>  	return 0;
>  }
>  
> +static int dnv_handle_irq(struct uart_port *p)
> +{
> +	struct mid8250 *mid = p->private_data;
> +	int ret;
> +
> +	ret = hsu_dma_irq(&mid->dma_chip, 0);
> +	ret |= hsu_dma_irq(&mid->dma_chip, 1);
> +
> +	/* For now, letting the HW generate separate interrupt for 
> the UART */
> +	if (ret)
> +		return ret;
> +
> +	return serial8250_handle_irq(p, serial_port_in(p, 
> UART_IIR));
> +}
> +
> +#define DNV_DMA_REGS	0x80
> +#define DNV_DMA_OFFSET	0x40
> +
> +static int dnv_setup(struct mid8250 *mid, struct uart_port *p)
> +{
> +	struct hsu_dma_chip *chip = &mid->dma_chip;
> +	struct pci_dev *pdev = to_pci_dev(p->dev);
> +	int ret;
> +
> +	chip->dev = &pdev->dev;
> +	chip->irq = pdev->irq;
> +	chip->regs = p->membase + DNV_DMA_REGS;
> +	chip->length = pci_resource_len(pdev, 0) - DNV_DMA_REGS;
> +	chip->offset = DNV_DMA_OFFSET;

This a bit buggy, since that offset stuff is coming for HSU PCI case
where we have
1) 0x100 bytes for global DMA registers (like interrupt)
2) 0x40 * nr_channels

So, in your case chip->offset should be 0, but _DMA_REGS should be
renamed to something like DMA_REGS_START since it's an offset to UART
register space.

> +
> +	ret = hsu_dma_probe(chip);
> +	if (ret)
> +		return ret;
> +
> +	mid->dma_dev = pdev;
> +
> +	p->handle_irq = dnv_handle_irq;
> +	return 0;
> +}
> +
> +static void dnv_exit(struct mid8250 *mid)
> +{
> +	hsu_dma_remove(&mid->dma_chip);
> +}
> +
>  /*******************************************************************
> **********/
>  
>  static void mid8250_set_termios(struct uart_port *p,
> @@ -202,22 +250,29 @@ static int mid8250_probe(struct pci_dev *pdev, 
> const struct pci_device_id *id)
>  
>  	ret = mid8250_dma_setup(mid, &uart);
>  	if (ret)
> -		return ret;
> +		goto err;
>  
>  	ret = serial8250_register_8250_port(&uart);
>  	if (ret < 0)
> -		return ret;
> +		goto err;
>  
>  	mid->line = ret;
>  
>  	pci_set_drvdata(pdev, mid);
>  	return 0;
> +err:
> +	if (mid->board->exit)
> +		mid->board->exit(mid);
> +	return ret;
>  }
>  
>  static void mid8250_remove(struct pci_dev *pdev)
>  {
>  	struct mid8250 *mid = pci_get_drvdata(pdev);
>  
> +	if (mid->board->exit)
> +		mid->board->exit(mid);
> +
>  	serial8250_unregister_port(mid->line);
>  }
>  
> @@ -233,6 +288,13 @@ static const struct mid8250_board tng_board = {
>  	.setup = tng_setup,
>  };
>  
> +static const struct mid8250_board dnv_board = {
> +	.freq = 133333333,
> +	.base_baud = 115200,
> +	.setup = dnv_setup,
> +	.exit = dnv_exit,
> +};
> +
>  #define MID_DEVICE(id, board) { PCI_VDEVICE(INTEL, id), 
> (kernel_ulong_t)&board }
>  
>  static const struct pci_device_id pci_ids[] = {
> @@ -240,6 +302,7 @@ static const struct pci_device_id pci_ids[] = {
>  	MID_DEVICE(PCI_DEVICE_ID_INTEL_PNW_UART2, pnw_board),
>  	MID_DEVICE(PCI_DEVICE_ID_INTEL_PNW_UART3, pnw_board),
>  	MID_DEVICE(PCI_DEVICE_ID_INTEL_TNG_UART, tng_board),
> +	MID_DEVICE(PCI_DEVICE_ID_INTEL_DNV_UART, dnv_board),
>  	{ },
>  };
>  MODULE_DEVICE_TABLE(pci, pci_ids);
> diff --git a/drivers/tty/serial/8250/8250_pci.c 
> b/drivers/tty/serial/8250/8250_pci.c
> index 177eaea..4097f3f 100644
> --- a/drivers/tty/serial/8250/8250_pci.c
> +++ b/drivers/tty/serial/8250/8250_pci.c
> @@ -3809,6 +3809,7 @@ static const struct pci_device_id blacklist[] = 
> {
>  	{ PCI_VDEVICE(INTEL, 0x081c), },
>  	{ PCI_VDEVICE(INTEL, 0x081d), },
>  	{ PCI_VDEVICE(INTEL, 0x1191), },
> +	{ PCI_VDEVICE(INTEL, 0x19d8), },
>  };
>  
>  /*

-- 
Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Intel Finland Oy
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