[U-Boot] [PATCH v2] mmc/dwmmc: use bounce buffer for data exchange between CPU and MMC controller

[Jaehoon Chung]

Hi, Alexey.

Acked-by: Jaehoon Chung <jh80.chung at samsung.com>
Tested-by: Jaehoon Chung <jh80.chung at samsung.com>

With Exynos4 board.

Best Regards,
Jaehoon Chung

On 12/26/2013 08:29 PM, Alexey Brodkin wrote:
> Bounce buffer implementation takes care of proper data buffer alignemt
> and correct flush/invalidation of data cache at once so we no longer
> depend on input data variety and make sure CPU and MMC controller deal
> with expected data in case of enabled data cache.
> 
> Bounce buffer requires to add its definition (CONFIG_BOUNCE_BUFFER) in
> board configuration, otherwise corresponding library won't be compiled
> and linker will fail to build resulting executable.
> 
> Difference since v1 - fixed compile-time warning with type casting to
> "void *":
> ====
> passing argument 2 of ‘bounce_buffer_start’ discards ‘const’ qualifier
> from pointer target type
> ====
> 
> Signed-off-by: Alexey Brodkin <abrodkin at synopsys.com>
> 
> Cc: Mischa Jonker <mjonker at synopsys.com>
> Cc: Alim Akhtar <alim.akhtar at samsung.com>
> Cc: Rajeshwari Shinde <rajeshwari.s at samsung.com>
> Cc: Jaehoon Chung <jh80.chung at samsung.com>
> Cc: Amar <amarendra.xt at samsung.com>
> Cc: Kyungmin Park <kyungmin.park at samsung.com>
> Cc: Minkyu Kang <mk7.kang at samsung.com>
> Cc: Simon Glass <sjg at chromium.org>
> Cc: Pantelis Antoniou <panto at antoniou-consulting.com>
> Cc: Andy Fleming <afleming at gmail.com>
> ---
>  drivers/mmc/dw_mmc.c            | 32 ++++++++++++++++++++++----------
>  include/configs/arndale.h       |  1 +
>  include/configs/exynos5250-dt.h |  1 +
>  3 files changed, 24 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/mmc/dw_mmc.c b/drivers/mmc/dw_mmc.c
> index 19d9b0b..1e34f36 100644
> --- a/drivers/mmc/dw_mmc.c
> +++ b/drivers/mmc/dw_mmc.c
> @@ -6,6 +6,7 @@
>   * SPDX-License-Identifier:	GPL-2.0+
>   */
>  
> +#include <bouncebuf.h>
>  #include <common.h>
>  #include <malloc.h>
>  #include <mmc.h>
> @@ -41,11 +42,13 @@ static void dwmci_set_idma_desc(struct dwmci_idmac *idmac,
>  }
>  
>  static void dwmci_prepare_data(struct dwmci_host *host,
> -		struct mmc_data *data, struct dwmci_idmac *cur_idmac)
> +			       struct mmc_data *data,
> +			       struct dwmci_idmac *cur_idmac,
> +			       void *bounce_buffer)
>  {
>  	unsigned long ctrl;
>  	unsigned int i = 0, flags, cnt, blk_cnt;
> -	ulong data_start, data_end, start_addr;
> +	ulong data_start, data_end;
>  
>  
>  	blk_cnt = data->blocks;
> @@ -55,11 +58,6 @@ static void dwmci_prepare_data(struct dwmci_host *host,
>  	data_start = (ulong)cur_idmac;
>  	dwmci_writel(host, DWMCI_DBADDR, (unsigned int)cur_idmac);
>  
> -	if (data->flags == MMC_DATA_READ)
> -		start_addr = (unsigned int)data->dest;
> -	else
> -		start_addr = (unsigned int)data->src;
> -
>  	do {
>  		flags = DWMCI_IDMAC_OWN | DWMCI_IDMAC_CH ;
>  		flags |= (i == 0) ? DWMCI_IDMAC_FS : 0;
> @@ -70,7 +68,7 @@ static void dwmci_prepare_data(struct dwmci_host *host,
>  			cnt = data->blocksize * 8;
>  
>  		dwmci_set_idma_desc(cur_idmac, flags, cnt,
> -				start_addr + (i * PAGE_SIZE));
> +				    (u32)bounce_buffer + (i * PAGE_SIZE));
>  
>  		if (blk_cnt <= 8)
>  			break;
> @@ -117,6 +115,7 @@ static int dwmci_send_cmd(struct mmc *mmc, struct mmc_cmd *cmd,
>  	u32 retry = 10000;
>  	u32 mask, ctrl;
>  	ulong start = get_timer(0);
> +	struct bounce_buffer bbstate;
>  
>  	while (dwmci_readl(host, DWMCI_STATUS) & DWMCI_BUSY) {
>  		if (get_timer(start) > timeout) {
> @@ -127,8 +126,19 @@ static int dwmci_send_cmd(struct mmc *mmc, struct mmc_cmd *cmd,
>  
>  	dwmci_writel(host, DWMCI_RINTSTS, DWMCI_INTMSK_ALL);
>  
> -	if (data)
> -		dwmci_prepare_data(host, data, cur_idmac);
> +	if (data) {
> +		if (data->flags == MMC_DATA_READ) {
> +			bounce_buffer_start(&bbstate, (void*)data->dest,
> +					    data->blocksize *
> +					    data->blocks, GEN_BB_WRITE);
> +		} else {
> +			bounce_buffer_start(&bbstate, (void*)data->src,
> +					    data->blocksize *
> +					    data->blocks, GEN_BB_READ);
> +		}
> +		dwmci_prepare_data(host, data, cur_idmac,
> +				   bbstate.bounce_buffer);
> +	}
>  
>  	dwmci_writel(host, DWMCI_CMDARG, cmd->cmdarg);
>  
> @@ -204,6 +214,8 @@ static int dwmci_send_cmd(struct mmc *mmc, struct mmc_cmd *cmd,
>  		ctrl = dwmci_readl(host, DWMCI_CTRL);
>  		ctrl &= ~(DWMCI_DMA_EN);
>  		dwmci_writel(host, DWMCI_CTRL, ctrl);
> +
> +		bounce_buffer_stop(&bbstate);
>  	}
>  
>  	udelay(100);
> diff --git a/include/configs/arndale.h b/include/configs/arndale.h
> index a3cb56b..3d29caf 100644
> --- a/include/configs/arndale.h
> +++ b/include/configs/arndale.h
> @@ -85,6 +85,7 @@
>  #define CONFIG_DWMMC
>  #define CONFIG_EXYNOS_DWMMC
>  #define CONFIG_SUPPORT_EMMC_BOOT
> +#define CONFIG_BOUNCE_BUFFER
>  
>  
>  #define CONFIG_BOARD_EARLY_INIT_F
> diff --git a/include/configs/exynos5250-dt.h b/include/configs/exynos5250-dt.h
> index 8fb904c..b39bafc 100644
> --- a/include/configs/exynos5250-dt.h
> +++ b/include/configs/exynos5250-dt.h
> @@ -102,6 +102,7 @@
>  #define CONFIG_DWMMC
>  #define CONFIG_EXYNOS_DWMMC
>  #define CONFIG_SUPPORT_EMMC_BOOT
> +#define CONFIG_BOUNCE_BUFFER
>  
>  
>  #define CONFIG_BOARD_EARLY_INIT_F
>