From: Arnd Bergmann <arnd@arndb.de>
To: Lee Jones <lee.jones@linaro.org>
Cc: linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linus.walleij@stericsson.com,
Russell King <linux@arm.linux.org.uk>,
Chris Ball <cjb@laptop.org>,
linux-mmc@vger.kernel.org
Subject: Re: [PATCH] mmc: mmci: Allow MMCI to request channels with information acquired from DT
Date: Wed, 17 Apr 2013 15:50:55 +0200 [thread overview]
Message-ID: <201304171550.56037.arnd@arndb.de> (raw)
In-Reply-To: <1366205534-25079-1-git-send-email-lee.jones@linaro.org>
On Wednesday 17 April 2013, Lee Jones wrote:
> #ifdef CONFIG_DMA_ENGINE
> -static void mmci_dma_setup(struct mmci_host *host)
> +static void mmci_dma_setup(struct amba_device *dev,
> + struct mmci_host *host)
> {
> + struct device_node *np = dev->dev.of_node;
> struct mmci_platform_data *plat = host->plat;
> const char *rxname, *txname;
> dma_cap_mask_t mask;
> + const char *chan_name;
> + int count, i;
> + bool do_tx = false, do_rx = false;
>
> if (!plat || !plat->dma_filter) {
> - dev_info(mmc_dev(host->mmc), "no DMA platform data\n");
> - return;
> + if (np) {
> + count = of_property_count_strings(np, "dma-names");
> + for (i = 0; i < count; i++) {
> + of_property_read_string_index(np, "dma-names",
> + i, &chan_name);
> + if (strcmp(chan_name, "tx"))
> + do_tx = true;
> + else if (strcmp(chan_name, "rx"))
> + do_rx = true;
> + }
> + } else {
> + dev_info(mmc_dev(host->mmc), "no DMA platform data\n");
> + return;
> + }
> }
This looks unnecessarily complex.
> /* initialize pre request cookie */
> @@ -321,19 +338,21 @@ static void mmci_dma_setup(struct mmci_host *host)
> * attempt to use it bidirectionally, however if it is
> * is specified but cannot be located, DMA will be disabled.
> */
> - if (plat->dma_rx_param) {
> - host->dma_rx_channel = dma_request_channel(mask,
> - plat->dma_filter,
> - plat->dma_rx_param);
> + if (plat->dma_rx_param || do_rx) {
> + host->dma_rx_channel = dma_request_slave_channel_compat(mask,
> + (plat) ? plat->dma_filter : NULL,
> + (plat) ? plat->dma_rx_param : NULL,
> + &dev->dev, "rx");
> /* E.g if no DMA hardware is present */
> if (!host->dma_rx_channel)
> dev_err(mmc_dev(host->mmc), "no RX DMA channel\n");
> }
Why not just do dma_request_slave_channel_compat() unconditionally here?
It's not an error for MMCI if that fails. If you want to keep the warning
in the case dma_rx_channel is provided by not working, you can do it like
host->dma_rx_channel = dma_request_slave_channel(dev, "rx");
if (!host->dma_rx_channel && plat->dma_rx_param) {
host->dma_rx_channel = dma_request_channel(mask,
plat->dma_filter,
plat->dma_rx_param);
...
}
Arnd
next prev parent reply other threads:[~2013-04-17 13:51 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-17 13:32 [PATCH] mmc: mmci: Allow MMCI to request channels with information acquired from DT Lee Jones
2013-04-17 13:50 ` Arnd Bergmann [this message]
2013-04-17 15:04 ` Lee Jones
2013-04-17 15:31 ` Arnd Bergmann
2013-04-18 8:02 ` Lee Jones
2013-04-18 8:15 ` Russell King - ARM Linux
2013-04-18 9:25 ` Arnd Bergmann
2013-04-18 9:30 ` Russell King - ARM Linux
2013-04-18 8:21 ` Ulf Hansson
2013-04-24 10:58 Lee Jones
2013-04-30 13:01 ` Linus Walleij
2013-04-30 13:12 ` Lee Jones
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=201304171550.56037.arnd@arndb.de \
--to=arnd@arndb.de \
--cc=cjb@laptop.org \
--cc=lee.jones@linaro.org \
--cc=linus.walleij@stericsson.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mmc@vger.kernel.org \
--cc=linux@arm.linux.org.uk \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).