Re: [PATCH] ARM: mmc: bcm281xx SDHCI driver
From: Christian Daudt
Date: Fri May 10 2013 - 04:28:15 EST
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@xxxxxxxxxxxx>
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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