linux-kernel - Re: [PATCH 06/44] staging: spmi: hisi-spmi-controller: use le32 macros where needed

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Date:   Wed, 12 Aug 2020 09:21:54 -0700
From:   Joe Perches <joe@...ches.com>
To:     Mauro Carvalho Chehab <mchehab+huawei@...nel.org>
Cc:     linuxarm@...wei.com, mauro.chehab@...wei.com,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-kernel@...r.kernel.org, devel@...verdev.osuosl.org
Subject: Re: [PATCH 06/44] staging: spmi: hisi-spmi-controller: use le32
 macros where needed

On Wed, 2020-08-12 at 17:56 +0200, Mauro Carvalho Chehab wrote:
> Instead of manually using bswap_32(), just use the
> le32 macros.

Are you certain this code will now work on any endian cpu?

Maybe just use __swab32 instead

> diff --git a/drivers/staging/hikey9xx/hisi-spmi-controller.c b/drivers/staging/hikey9xx/hisi-spmi-controller.c
[]
> @@ -43,11 +42,6 @@
>  #define SPMI_APB_SPMI_CMD_TYPE_OFFSET			24
>  #define SPMI_APB_SPMI_CMD_LENGTH_OFFSET			20
>  
> -#define bswap_32(X)   \
> -    ((((u32)(X) & 0xff000000) >> 24) | \
> -     (((u32)(X) & 0x00ff0000) >> 8) | \
> -     (((u32)(X) & 0x0000ff00) << 8) | \
> -     (((u32)(X) & 0x000000ff) << 24))
>  #define SPMI_APB_SPMI_CMD_SLAVEID_OFFSET		16
>  #define SPMI_APB_SPMI_CMD_ADDR_OFFSET			0
>  
> @@ -179,14 +173,15 @@ static int spmi_read_cmd(struct spmi_controller *ctrl,
>  
>  	writel(cmd, spmi_controller->base + chnl_ofst + SPMI_APB_SPMI_CMD_BASE_ADDR);
>  
> -	rc = spmi_controller_wait_for_done(spmi_controller, spmi_controller->base, sid, addr);
> +	rc = spmi_controller_wait_for_done(spmi_controller,
> +					   spmi_controller->base, sid, addr);
>  	if (rc)
>  		goto done;
>  
>  	i = 0;
>  	do {
>  		data = readl(spmi_controller->base + chnl_ofst + SPMI_SLAVE_OFFSET * sid + SPMI_APB_SPMI_RDATA0_BASE_ADDR + i * SPMI_PER_DATAREG_BYTE);
> -		data = bswap_32(data);
> +		data = be32_to_cpu((__be32)data);
>  		if ((bc - i * SPMI_PER_DATAREG_BYTE) >> 2) {
>  			memcpy(buf, &data, sizeof(data));
>  			buf += sizeof(data);
> @@ -210,8 +205,7 @@ static int spmi_write_cmd(struct spmi_controller *ctrl,
>  {
>  	struct spmi_controller_dev *spmi_controller = dev_get_drvdata(&ctrl->dev);
>  	unsigned long flags;
> -	u32 cmd;
> -	u32 data = 0;
> +	u32 cmd, data;
>  	int rc;
>  	u32 chnl_ofst = SPMI_CHANNEL_OFFSET * spmi_controller->channel;
>  	u8 op_code, i;
> @@ -246,7 +240,7 @@ static int spmi_write_cmd(struct spmi_controller *ctrl,
>  
>  	i = 0;
>  	do {
> -		memset(&data, 0, sizeof(data));
> +		data = 0;
>  		if ((bc - i * SPMI_PER_DATAREG_BYTE) >> 2) {
>  			memcpy(&data, buf, sizeof(data));
>  			buf += sizeof(data);
> @@ -255,8 +249,8 @@ static int spmi_write_cmd(struct spmi_controller *ctrl,
>  			buf += (bc % SPMI_PER_DATAREG_BYTE);
>  		}
>  
> -		data = bswap_32(data);
> -		writel(data, spmi_controller->base + chnl_ofst + SPMI_APB_SPMI_WDATA0_BASE_ADDR + SPMI_PER_DATAREG_BYTE * i);
> +		writel((u32)cpu_to_be32(data),
> +		       spmi_controller->base + chnl_ofst + SPMI_APB_SPMI_WDATA0_BASE_ADDR + SPMI_PER_DATAREG_BYTE * i);
>  		i++;
>  	} while (bc > i * SPMI_PER_DATAREG_BYTE);
>