[U-Boot] [PATCH v2 1/4] dma: lpc32xx: add DMA driver

[Marek Vasut <marex@denx.de>]

On Wednesday, July 29, 2015 at 06:14:07 PM, slemieux.tyco at gmail.com wrote:
> From: Sylvain Lemieux <slemieux@tycoint.com>
> 
> Incorporate DMA driver from legacy LPCLinux NXP BSP.
> The files taken from the legacy patch are:
> - lpc32xx DMA driver
> - lpc3250 header file DMA registers definition.
> 
> The legacy driver was updated to integrate with the latest u-boot.
> 
> Signed-off-by: Sylvain Lemieux <slemieux@tycoint.com>

[...]

> diff --git a/drivers/dma/lpc32xx_dma.c b/drivers/dma/lpc32xx_dma.c
> new file mode 100644
> index 0000000..feb16ce
> --- /dev/null
> +++ b/drivers/dma/lpc32xx_dma.c
> @@ -0,0 +1,153 @@
> +/*
> + * Copyright (C) 2008-2015 by NXP Semiconductors
> + * All rights reserved.
> + *
> + * @Author: Kevin Wells
> + * @Descr: LPC3250 DMA controller interface support functions
> + *
> + * See file CREDITS for list of people who contributed to this
> + * project.
> + *
> + * SPDX-License-Identifier:	GPL-2.0+
> + */
> +
> +#include <common.h>
> +#include <asm/arch/dma.h>
> +#include <asm/arch/cpu.h>
> +#include <asm/arch/clk.h>
> +#include <asm/arch/sys_proto.h>
> +#include <asm/io.h>
> +
> +/* Some optimization stuff */
> +#ifndef unlikely
> +#define likely(x)	__builtin_expect(!!(x), 1)
> +#define unlikely(x)	__builtin_expect(!!(x), 0)
> +#endif

This is defined in include/compiler.h

> +/* bit position macro */
> +#define _BIT(n)		(0x1 << (n))

Drop this as well please.

> +/* DMA controller channel register structure */
> +struct dmac_chan_reg {
> +	uint32_t src_addr;
> +	uint32_t dest_addr;
> +	uint32_t lli;
> +	uint32_t control;
> +	uint32_t config_ch;
> +	uint32_t reserved[3];
> +};
> +
> +/* DMA controller register structures */
> +struct dma_reg {
> +	uint32_t int_stat;
> +	uint32_t int_tc_stat;
> +	uint32_t int_tc_clear;
> +	uint32_t int_err_stat;
> +	uint32_t int_err_clear;
> +	uint32_t raw_tc_stat;
> +	uint32_t raw_err_stat;
> +	uint32_t chan_enable;
> +	uint32_t sw_burst_req;
> +	uint32_t sw_single_req;
> +	uint32_t sw_last_burst_req;
> +	uint32_t sw_last_single_req;
> +	uint32_t config;
> +	uint32_t sync;
> +	uint32_t reserved[50];
> +	struct dmac_chan_reg dma_chan[8];
> +};
> +
> +/* Macro pointing to DMA registers */
> +#define DMA_NO_OF_CHANNELS	8
> +
> +/* config register definitions */
> +#define DMAC_CTRL_ENABLE	(1 << 0) /* For enabling the DMA controller */
> +
> +static uint32_t alloc_ch;
> +
> +static struct dma_reg *dma = (struct dma_reg *)DMA_BASE;
> +
> +int lpc32xx_dma_get_channel(void)
> +{
> +	int i;
> +	uint32_t status = 0;
> +
> +	if (!alloc_ch) { /* First time caller */
> +		/* DMA clock are enable by "lpc32xx_dma_init()" and should
> +		 * be call by board "board_early_init_f()" function. */
> +
> +		/* Make sure DMA controller and all channels are disabled.
> +		 * Controller is in little-endian mode. Disable sync signals */
> +		writel(0, &dma->config);
> +		writel(0, &dma->sync);
> +
> +		/* Clear interrupt and error statuses */
> +		writel(0xFF, &dma->int_tc_clear);
> +		writel(0xFF, &dma->raw_tc_stat);
> +		writel(0xFF, &dma->int_err_clear);
> +		writel(0xFF, &dma->raw_err_stat);
> +
> +		/* Enable DMA controller */
> +		writel(DMAC_CTRL_ENABLE, &dma->config);
> +	}
> +
> +	for (i = 0; i < DMA_NO_OF_CHANNELS && (status & _BIT(i)); i++)
> +		;

I think you should look at ffs() and fls() in include/linux/bitops.h here.

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