From mboxrd@z Thu Jan  1 00:00:00 1970
From: svenkatr@ti.com (S, Venkatraman)
Date: Thu, 16 Jun 2011 18:44:47 +0530
Subject: [PATCH v4 03/12] omap_hsmmc: add support for pre_req and post_req
In-Reply-To: <1306360653-6196-4-git-send-email-per.forlin@linaro.org>
References: <1306360653-6196-1-git-send-email-per.forlin@linaro.org>
	<1306360653-6196-4-git-send-email-per.forlin@linaro.org>
Message-ID: <BANLkTikP8pveKPPG+_h6_hBenh91vAi4mQ@mail.gmail.com>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Thu, May 26, 2011 at 3:27 AM, Per Forlin <per.forlin@linaro.org> wrote:
> pre_req() runs dma_map_sg(), post_req() runs dma_unmap_sg.
> If not calling pre_req() before omap_hsmmc_request()
> dma_map_sg will be issued before starting the transfer.
> It is optional to use pre_req(). If issuing pre_req()
> post_req() must be to be called as well.
>
> Signed-off-by: Per Forlin <per.forlin@linaro.org>
> ---
> ?drivers/mmc/host/omap_hsmmc.c | ? 87 +++++++++++++++++++++++++++++++++++++++--
> ?1 files changed, 83 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c
> index ad3731a..2116c09 100644
> --- a/drivers/mmc/host/omap_hsmmc.c
> +++ b/drivers/mmc/host/omap_hsmmc.c
> @@ -141,6 +141,11 @@
> ?#define OMAP_HSMMC_WRITE(base, reg, val) \
> ? ? ? ?__raw_writel((val), (base) + OMAP_HSMMC_##reg)
>
> +struct omap_hsmmc_next {
> + ? ? ? unsigned int ? ?dma_len;
> + ? ? ? s32 ? ? ? ? ? ? cookie;
> +};
> +
> ?struct omap_hsmmc_host {
> ? ? ? ?struct ?device ? ? ? ? ?*dev;
> ? ? ? ?struct ?mmc_host ? ? ? ?*mmc;
> @@ -184,6 +189,7 @@ struct omap_hsmmc_host {
> ? ? ? ?int ? ? ? ? ? ? ? ? ? ? reqs_blocked;
> ? ? ? ?int ? ? ? ? ? ? ? ? ? ? use_reg;
> ? ? ? ?int ? ? ? ? ? ? ? ? ? ? req_in_progress;
> + ? ? ? struct omap_hsmmc_next ?next_data;
>
> ? ? ? ?struct ?omap_mmc_platform_data ?*pdata;
> ?};
> @@ -1344,8 +1350,9 @@ static void omap_hsmmc_dma_cb(int lch, u16 ch_status, void *cb_data)
> ? ? ? ? ? ? ? ?return;
> ? ? ? ?}
>
> - ? ? ? dma_unmap_sg(mmc_dev(host->mmc), data->sg, data->sg_len,
> - ? ? ? ? ? ? ? omap_hsmmc_get_dma_dir(host, data));
> + ? ? ? if (!data->host_cookie)
> + ? ? ? ? ? ? ? dma_unmap_sg(mmc_dev(host->mmc), data->sg, data->sg_len,
> + ? ? ? ? ? ? ? ? ? ? ? ? ? ?omap_hsmmc_get_dma_dir(host, data));
>
> ? ? ? ?req_in_progress = host->req_in_progress;
> ? ? ? ?dma_ch = host->dma_ch;
> @@ -1363,6 +1370,45 @@ static void omap_hsmmc_dma_cb(int lch, u16 ch_status, void *cb_data)
> ? ? ? ?}
> ?}
>
> +static int omap_hsmmc_pre_dma_transfer(struct omap_hsmmc_host *host,
> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?struct mmc_data *data,
> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?struct omap_hsmmc_next *next)
> +{

As you are passing &host->next_data into next, next will always be a
valid pointer. So..

> + ? ? ? int dma_len;
> +
> + ? ? ? if (!next && data->host_cookie &&
> + ? ? ? ? ? data->host_cookie != host->next_data.cookie) {

!next will always return false and hence the rest of the check will
never be executed.
Perhaps s/&&/||/g ?


> + ? ? ? ? ? ? ? printk(KERN_WARNING "[%s] invalid cookie: data->host_cookie %d"
> + ? ? ? ? ? ? ? ? ? ? ?" host->next_data.cookie %d\n",
> + ? ? ? ? ? ? ? ? ? ? ?__func__, data->host_cookie, host->next_data.cookie);
> + ? ? ? ? ? ? ? data->host_cookie = 0;
> + ? ? ? }
> +
> + ? ? ? /* Check if next job is already prepared */
> + ? ? ? if (next ||
> + ? ? ? ? ? (!next && data->host_cookie != host->next_data.cookie)) {

Cookie matching will never be checked..

> + ? ? ? ? ? ? ? dma_len = dma_map_sg(mmc_dev(host->mmc), data->sg,
> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?data->sg_len,
> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?omap_hsmmc_get_dma_dir(host, data));
> +
> + ? ? ? } else {

and this will never be executed as well?

> + ? ? ? ? ? ? ? dma_len = host->next_data.dma_len;
> + ? ? ? ? ? ? ? host->next_data.dma_len = 0;
> + ? ? ? }
> +
> +
> + ? ? ? if (dma_len == 0)
> + ? ? ? ? ? ? ? return -EINVAL;
> +
> + ? ? ? if (next) {
> + ? ? ? ? ? ? ? next->dma_len = dma_len;
> + ? ? ? ? ? ? ? data->host_cookie = ++next->cookie < 0 ? 1 : next->cookie;
> + ? ? ? } else
> + ? ? ? ? ? ? ? host->dma_len = dma_len;
> +
> + ? ? ? return 0;
> +}
> +