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Message-ID: <518CA1DF.5050008@broadcom.com>
Date: Fri, 10 May 2013 00:29:35 -0700
From: "Christian Daudt" <csd@...adcom.com>
To: "Jean-Christophe PLAGNIOL-VILLARD" <plagnioj@...osoft.com>
cc: "Grant Likely" <grant.likely@...retlab.ca>,
"Rob Herring" <rob.herring@...xeda.com>,
"Rob Landley" <rob@...dley.net>,
"Russell King" <linux@....linux.org.uk>,
"Chris Ball" <cjb@...top.org>,
"Stephen Warren" <swarren@...dia.com>,
"Olof Johansson" <olof@...om.net>,
"Greg Kroah-Hartman" <gregkh@...uxfoundation.org>,
"Wei WANG" <wei_wang@...lsil.com.cn>,
"Ludovic Desroches" <ludovic.desroches@...el.com>,
"Arnd Bergmann" <arnd@...db.de>,
"Mike A. Chan" <mikechan@...gle.com>,
devicetree-discuss@...ts.ozlabs.org, linux-doc@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
linux-mmc@...r.kernel.org, csd_b@...dt.org
Subject: Re: [PATCH] ARM: mmc: bcm281xx SDHCI driver
Thanks for the feedback.
On 13-05-08 11:35 PM, Jean-Christophe PLAGNIOL-VILLARD wrote:
> On 22:55 Wed 08 May , Christian Daudt wrote:
>> Add SDHCI driver for the Broadcom 281xx SoCs. Also
>> add bindings for it into bcm281xx dts files.
>> Still missing:
>> - power managemement
> split the dts/dtsi in an other patch
ok.
>> Signed-off-by: Christian Daudt <csd@...adcom.com>
>>
>> diff --git a/arch/arm/configs/bcm_defconfig b/arch/arm/configs/bcm_defconfig
>> index e3bf2d6..65edf6d 100644
>> --- a/arch/arm/configs/bcm_defconfig
>> +++ b/arch/arm/configs/bcm_defconfig
>> @@ -78,6 +78,13 @@ CONFIG_BACKLIGHT_LCD_SUPPORT=y
>> CONFIG_LCD_CLASS_DEVICE=y
>> CONFIG_BACKLIGHT_CLASS_DEVICE=y
>> # CONFIG_USB_SUPPORT is not set
>> +CONFIG_MMC=y
>> +CONFIG_MMC_UNSAFE_RESUME=y
>> +CONFIG_MMC_BLOCK_MINORS=32
>> +CONFIG_MMC_TEST=y
>> +CONFIG_MMC_SDHCI=y
>> +CONFIG_MMC_SDHCI_PLTFM=y
>> +CONFIG_MMC_SDHCI_BCM_KONA=y
>> CONFIG_NEW_LEDS=y
>> CONFIG_LEDS_CLASS=y
>> CONFIG_LEDS_TRIGGERS=y
>> diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
>> index d88219e..e067c5a 100644
>> --- a/drivers/mmc/host/Kconfig
>> +++ b/drivers/mmc/host/Kconfig
>> @@ -238,6 +238,16 @@ config MMC_SDHCI_S3C_DMA
>>
>> YMMV.
>>
>> +config MMC_SDHCI_BCM_KONA
>> + tristate "SDHCI support on Broadcom KONA platform"
>> + depends on ARCH_BCM && MMC_SDHCI_PLTFM
> select MMC_SDHCI_PLTFM
> will be better
Ok - changed it. Why is the select is better than the depends ?
>> +
>> +static int sdhci_bcm_kona_sd_reset(struct sdhci_host *host)
>> +{
>> + unsigned int val;
>> + unsigned long timeout;
>> +
>> + /* This timeout should be sufficent for core to reset */
>> + timeout = jiffies + msecs_to_jiffies(100);
>> +
>> + /* reset the host using the top level reset */
>> + val = sdhci_readl(host, KONA_SDHOST_CORECTRL);
>> + val |= KONA_SDHOST_RESET;
>> + sdhci_writel(host, val, KONA_SDHOST_CORECTRL);
>> +
>> + while (!(sdhci_readl(host, KONA_SDHOST_CORECTRL) & KONA_SDHOST_RESET)) {
>> + if (time_is_before_jiffies(timeout)) {
>> + pr_err("Error: sd host is stuck in reset!!!\n");
>> + return -EFAULT;
>> + }
>> + }
>> +
>> + /* bring the host out of reset */
>> + val = sdhci_readl(host, KONA_SDHOST_CORECTRL);
>> + val &= ~KONA_SDHOST_RESET;
>> +
>> + /*
>> + * Back-to-Back register write needs a delay of 1ms at bootup (min 10uS)
>> + * Back-to-Back writes to same register needs delay when SD bus clock
>> + * is very low w.r.t AHB clock, mainly during boot-time and during card
>> + * insert-removal.
>> + */
>> + udelay(1000);
> really a udelay of 1ms
I'm trying to clarify on whether this is really necessary but it does
seem that this is the case. I'll send a follow-up patch if I manage to
get confirmation on a smaller safe number.
>> + sdhci_writel(host, val, KONA_SDHOST_CORECTRL);
>> +
>> + return 0;
>> +}
>> +
>> +static void sdhci_bcm_kona_sd_init(struct sdhci_host *host)
>> +{
>> + unsigned int val;
>> +
>> + /* enable the interrupt from the IP core */
>> + val = sdhci_readl(host, KONA_SDHOST_COREIMR);
>> + val |= KONA_SDHOST_IP;
>> + sdhci_writel(host, val, KONA_SDHOST_COREIMR);
>> +
>> + /* Enable the AHB clock gating module to the host */
>> + val = sdhci_readl(host, KONA_SDHOST_CORECTRL);
>> + val |= KONA_SDHOST_EN;
>> +
>> + /*
>> + * Back-to-Back register write needs a delay of 1ms at bootup (min 10uS)
>> + * Back-to-Back writes to same register needs delay when SD bus clock
>> + * is very low w.r.t AHB clock, mainly during boot-time and during card
>> + * insert-removal.
>> + */
>> + udelay(1000);
> ditto
see above
>> + sdhci_writel(host, val, KONA_SDHOST_CORECTRL);
>> +}
>> +
>> +/*
>> + * Software emulation of the SD card insertion/removal. Set insert=1 for insert
>> + * and insert=0 for removal. The card detection is done by GPIO. For Broadcom
>> + * IP to function properly the bit 0 of CORESTAT register needs to be set/reset
>> + * to generate the CD IRQ handled in sdhci.c which schedules card_tasklet.
>> + */
>> +static int sdhci_bcm_kona_sd_card_emulate(struct sdhci_host *host, int insert)
>> +{
>> + struct sdhci_pltfm_host *pltfm_priv = sdhci_priv(host);
>> + struct sdhci_bcm_kona_dev *kona_dev = pltfm_priv->priv;
>> + u32 val;
>> + unsigned long flags;
>> +
>> + /* this function can be called from various contexts including ISR */
>> + spin_lock_irqsave(&host->lock, flags);
>> + /* Ensure SD bus scanning to detect media change */
>> + host->mmc->rescan_disable = 0;
>> +
>> + /*
>> + * Back-to-Back register write needs a delay of min 10uS.
>> + * Back-to-Back writes to same register needs delay when SD bus clock
>> + * is very low w.r.t AHB clock, mainly during boot-time and during card
>> + * insert-removal.
>> + * We keep 20uS
>> + */
>> + udelay(20);
>> + val = sdhci_readl(host, KONA_SDHOST_CORESTAT);
>> +
>> + if (insert) {
>> + if (kona_dev->cfg->wp_gpio >= 0) {
> gpio_is_valid
done
>> + int wp_status = gpio_get_value(kona_dev->cfg->wp_gpio);
>> +
>> + if (wp_status)
>> + val |= KONA_SDHOST_WP;
>> + else
>> + val &= ~KONA_SDHOST_WP;
>> + }
>> +
>> + val |= KONA_SDHOST_CD_SW;
>> + sdhci_writel(host, val, KONA_SDHOST_CORESTAT);
>> + } else {
>> + val &= ~KONA_SDHOST_CD_SW;
>> + sdhci_writel(host, val, KONA_SDHOST_CORESTAT);
>> + }
>> + spin_unlock_irqrestore(&host->lock, flags);
>> +
>> + return 0;
>> +}
>> +
>> +/*
>> + * SD card detection interrupt handler
>> + */
>> +static irqreturn_t sdhci_bcm_kona_pltfm_cd_interrupt(int irq, void *host)
>> +{
>> + struct sdhci_pltfm_host *pltfm_priv = sdhci_priv(host);
>> + struct sdhci_bcm_kona_dev *kona_dev = pltfm_priv->priv;
>> +
>> + if (gpio_get_value_cansleep(kona_dev->cfg->cd_gpio) == 0) {
>> + pr_debug("card inserted\n");
> dev_dbg
done
>> + sdhci_bcm_kona_sd_card_emulate(host, 1);
>> + } else {
>> + pr_debug("card removed\n");
> ditto
done
>> +static struct sdhci_bcm_kona_cfg * __init sdhci_bcm_kona_parse_dt(
>> + struct platform_device *pdev)
>> +{
>> + struct sdhci_bcm_kona_cfg *cfg;
>> + struct device_node *np = pdev->dev.of_node;
>> + u32 temp;
>> +
>> + if (!np)
>> + return NULL;
>> +
>> + cfg = devm_kzalloc(&pdev->dev, sizeof(*cfg), GFP_KERNEL);
>> + if (!cfg) {
>> + dev_err(&pdev->dev, "Can't allocate platform cfg\n");
>> + return NULL;
>> + }
>> +
>> + cfg->cd_gpio = of_get_named_gpio(np, "cd-gpios", 0);
>> + cfg->wp_gpio = of_get_named_gpio(np, "wp-gpios", 0);
>> + if (of_get_property(np, "non-removable", NULL))
>> + cfg->non_removable = 1;
> use of_property_read_bool
done
>> + /* Sleep for 128ms to allow debounce to stabilize */
>> + msleep(SD_DETECT_GPIO_DEBOUNCE_128MS);
>> + /* request irq for cd_gpio after the gpio debounce is
>> + * stabilized, otherwise, some bogus gpio interrupts might be
>> + * triggered.
>> + */
>> + irq = gpio_to_irq(kona_dev->cfg->cd_gpio);
>> + ret = devm_request_threaded_irq(dev,
>> + irq,
>> + NULL,
>> + sdhci_bcm_kona_pltfm_cd_interrupt,
>> + IRQF_TRIGGER_FALLING|
>> + IRQF_TRIGGER_RISING |
>> + IRQF_ONESHOT |
>> + IRQF_NO_SUSPEND, "sdio cd", host);
>> + if (ret) {
>> + dev_err(kona_dev->dev,
>> + "Unable to request card detection irq=%d"
>> + " for gpio=%d ret=%d\n",
> put the sting of the dev_err on one line so we can grep
merged it into single line
Thanks,
csd
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