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SubjectRe: [PATCH v2 2/2] mmc: Add support for the ASPEED SD controller
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On 12/07/19 6:32 AM, Andrew Jeffery wrote:
> Add a minimal driver for ASPEED's SD controller, which exposes two
> SDHCIs.
>
> The ASPEED design implements a common register set for the SDHCIs, and
> moves some of the standard configuration elements out to this common
> area (e.g. 8-bit mode, and card detect configuration which is not
> currently supported).
>
> The SD controller has a dedicated hardware interrupt that is shared
> between the slots. The common register set exposes information on which
> slot triggered the interrupt; early revisions of the patch introduced an
> irqchip for the register, but reality is it doesn't behave as an
> irqchip, and the result fits awkwardly into the irqchip APIs. Instead
> I've taken the simple approach of using the IRQ as a shared IRQ with
> some minor performance impact for the second slot.
>
> Ryan was the original author of the patch - I've taken his work and
> massaged it to drop the irqchip support and rework the devicetree
> integration. The driver has been smoke tested under qemu against a
> minimal SD controller model and lightly tested on an ast2500-evb.
>
> Signed-off-by: Ryan Chen <ryanchen.aspeed@gmail.com>
> Signed-off-by: Andrew Jeffery <andrew@aj.id.au>

Looks fine. Few minor comments below.

> ---
> In v2:
>
> * Drop unnecesasry MODULE_DEVICE_TABLE()
> * Rename sd-controller compatible
> * Add IBM copyright
> * Drop unnecesary data assignment in of match table entries
> * Derive the slot from the SDHCI offset
>
> drivers/mmc/host/Kconfig | 12 ++
> drivers/mmc/host/Makefile | 1 +
> drivers/mmc/host/sdhci-of-aspeed.c | 326 +++++++++++++++++++++++++++++
> 3 files changed, 339 insertions(+)
> create mode 100644 drivers/mmc/host/sdhci-of-aspeed.c
>
> diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
> index 931770f17087..2bb5e1264b3d 100644
> --- a/drivers/mmc/host/Kconfig
> +++ b/drivers/mmc/host/Kconfig
> @@ -154,6 +154,18 @@ config MMC_SDHCI_OF_ARASAN
>
> If unsure, say N.
>
> +config MMC_SDHCI_OF_ASPEED
> + tristate "SDHCI OF support for the ASPEED SDHCI controller"
> + depends on MMC_SDHCI_PLTFM
> + depends on OF
> + help
> + This selects the ASPEED Secure Digital Host Controller Interface.
> +
> + If you have a controller with this interface, say Y or M here. You
> + also need to enable an appropriate bus interface.
> +
> + If unsure, say N.
> +
> config MMC_SDHCI_OF_AT91
> tristate "SDHCI OF support for the Atmel SDMMC controller"
> depends on MMC_SDHCI_PLTFM
> diff --git a/drivers/mmc/host/Makefile b/drivers/mmc/host/Makefile
> index 73578718f119..390ee162fe71 100644
> --- a/drivers/mmc/host/Makefile
> +++ b/drivers/mmc/host/Makefile
> @@ -84,6 +84,7 @@ obj-$(CONFIG_MMC_SDHCI_ESDHC_IMX) += sdhci-esdhc-imx.o
> obj-$(CONFIG_MMC_SDHCI_DOVE) += sdhci-dove.o
> obj-$(CONFIG_MMC_SDHCI_TEGRA) += sdhci-tegra.o
> obj-$(CONFIG_MMC_SDHCI_OF_ARASAN) += sdhci-of-arasan.o
> +obj-$(CONFIG_MMC_SDHCI_OF_ASPEED) += sdhci-of-aspeed.o
> obj-$(CONFIG_MMC_SDHCI_OF_AT91) += sdhci-of-at91.o
> obj-$(CONFIG_MMC_SDHCI_OF_ESDHC) += sdhci-of-esdhc.o
> obj-$(CONFIG_MMC_SDHCI_OF_HLWD) += sdhci-of-hlwd.o
> diff --git a/drivers/mmc/host/sdhci-of-aspeed.c b/drivers/mmc/host/sdhci-of-aspeed.c
> new file mode 100644
> index 000000000000..9528e43c257d
> --- /dev/null
> +++ b/drivers/mmc/host/sdhci-of-aspeed.c
> @@ -0,0 +1,326 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/* Copyright (C) 2019 ASPEED Technology Inc. */
> +/* Copyright (C) 2019 IBM Corp. */
> +
> +#include <linux/clk.h>
> +#include <linux/delay.h>
> +#include <linux/device.h>
> +#include <linux/io.h>
> +#include <linux/mmc/host.h>
> +#include <linux/module.h>
> +#include <linux/of_address.h>
> +#include <linux/of.h>
> +#include <linux/of_platform.h>
> +#include <linux/platform_device.h>
> +#include <linux/spinlock.h>
> +
> +#include "sdhci-pltfm.h"
> +
> +#define ASPEED_SDC_INFO 0x00
> +#define ASPEED_SDC_S1MMC8 BIT(25)
> +#define ASPEED_SDC_S0MMC8 BIT(24)
> +
> +struct aspeed_sdc {
> + struct clk *clk;
> + struct resource *res;
> +
> + spinlock_t lock;
> + void __iomem *regs;
> +};
> +
> +struct aspeed_sdhci {
> + struct aspeed_sdc *parent;
> + u32 width_mask;
> +};
> +
> +static void aspeed_sdc_bus_width(struct aspeed_sdc *sdc,
> + struct aspeed_sdhci *sdhci, bool bus8)

The function name threw me at first. I suggest:

static void aspeed_sdhci_set_clr_8_bit_mode(struct aspeed_sdhci *aspeed_sdhci,
bool bus8)
{
struct aspeed_sdc *aspeed_sdc = aspeed_sdhci->parent;

> +{
> + u32 info;
> +
> + /* Set/clear 8 bit mode */
> + spin_lock(&sdc->lock);
> + info = readl(sdc->regs + ASPEED_SDC_INFO);
> + if (bus8)
> + info |= sdhci->width_mask;
> + else
> + info &= ~sdhci->width_mask;
> + writel(info, sdc->regs + ASPEED_SDC_INFO);
> + spin_unlock(&sdc->lock);
> +}
> +
> +static void aspeed_sdhci_set_clock(struct sdhci_host *host, unsigned int clock)
> +{
> + unsigned long timeout;
> + int div;
> + u16 clk;
> +
> + if (clock == host->clock)
> + return;
> +
> + sdhci_writew(host, 0, SDHCI_CLOCK_CONTROL);
> +
> + if (clock == 0)
> + goto out;
> +
> + for (div = 1; div < 256; div *= 2) {
> + if ((host->max_clk / div) <= clock)
> + break;
> + }
> + div >>= 1;
> +
> + clk = div << SDHCI_DIVIDER_SHIFT;

Could call sdhci_enable_clk() here.

> + clk |= SDHCI_CLOCK_INT_EN;
> + sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
> +
> + /* Wait max 20 ms */
> + timeout = 20;
> + while (!((clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL))
> + & SDHCI_CLOCK_INT_STABLE)) {
> + if (timeout == 0) {
> + pr_err("%s: Internal clock never stabilised.\n",
> + mmc_hostname(host->mmc));
> + return;
> + }
> + timeout--;
> + mdelay(1);
> + }
> +
> + clk |= SDHCI_CLOCK_CARD_EN;
> + sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
> +
> +out:
> + host->clock = clock;
> +}
> +
> +static void aspeed_sdhci_set_bus_width(struct sdhci_host *host, int width)
> +{
> + struct sdhci_pltfm_host *pltfm_priv;
> + struct aspeed_sdhci *aspeed_sdhci;
> + struct aspeed_sdc *aspeed_sdc;
> + u8 ctrl;
> +
> + pltfm_priv = sdhci_priv(host);
> + aspeed_sdhci = sdhci_pltfm_priv(pltfm_priv);
> + aspeed_sdc = aspeed_sdhci->parent;
> +
> + /* Set/clear 8-bit mode */
> + aspeed_sdc_bus_width(aspeed_sdc, aspeed_sdhci,
> + width == MMC_BUS_WIDTH_8);
> +
> + /* Set/clear 1 or 4 bit mode */
> + ctrl = sdhci_readb(host, SDHCI_HOST_CONTROL);
> + if (width == MMC_BUS_WIDTH_4)
> + ctrl |= SDHCI_CTRL_4BITBUS;
> + else
> + ctrl &= ~SDHCI_CTRL_4BITBUS;
> + sdhci_writeb(host, ctrl, SDHCI_HOST_CONTROL);
> +}
> +
> +static const struct sdhci_ops aspeed_sdhci_ops = {
> + .set_clock = aspeed_sdhci_set_clock,
> + .get_max_clock = sdhci_pltfm_clk_get_max_clock,
> + .set_bus_width = aspeed_sdhci_set_bus_width,
> + .get_timeout_clock = sdhci_pltfm_clk_get_max_clock,
> + .reset = sdhci_reset,
> + .set_uhs_signaling = sdhci_set_uhs_signaling,
> +};
> +
> +static const struct sdhci_pltfm_data aspeed_sdc_pdata = {

Up to you, but this is for the aspeed_sdhci driver, so I would
have expected it to be called aspeed_sdhci_pdata

> + .ops = &aspeed_sdhci_ops,
> + .quirks = SDHCI_QUIRK_CAP_CLOCK_BASE_BROKEN,
> + .quirks2 = SDHCI_QUIRK2_CLOCK_DIV_ZERO_BROKEN,

You don't use sdhci_set_clock() or sdhci_calc_clk(), so it doesn't
look like SDHCI_QUIRK2_CLOCK_DIV_ZERO_BROKEN is needed.

> +};
> +
> +static inline int aspeed_sdhci_calculate_slot(struct aspeed_sdhci *dev,
> + struct resource *res)
> +{
> + resource_size_t delta;
> +
> + if (!res || resource_type(res) != IORESOURCE_MEM)
> + return -EINVAL;
> +
> + if (res->start < dev->parent->res->start)
> + return -EINVAL;
> +
> + delta = res->start - dev->parent->res->start;
> + if (delta & (0x100 - 1))
> + return -EINVAL;
> +
> + return (delta / 0x100) - 1;
> +}
> +
> +static int aspeed_sdhci_probe(struct platform_device *pdev)
> +{
> + struct sdhci_pltfm_host *pltfm_host;
> + struct aspeed_sdhci *dev;
> + struct sdhci_host *host;
> + struct resource *res;
> + int slot;
> + int ret;
> +
> + host = sdhci_pltfm_init(pdev, &aspeed_sdc_pdata, sizeof(*dev));
> + if (IS_ERR(host))
> + return PTR_ERR(host);
> +
> + pltfm_host = sdhci_priv(host);
> + dev = sdhci_pltfm_priv(pltfm_host);
> + dev->parent = dev_get_drvdata(pdev->dev.parent);
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + slot = aspeed_sdhci_calculate_slot(dev, res);
> + if (slot < 0)
> + return slot;
> + dev_info(&pdev->dev, "Configuring for slot %d\n", slot);
> + dev->width_mask = !slot ? ASPEED_SDC_S0MMC8 : ASPEED_SDC_S1MMC8;

That implies that you only support 2 slots which begs the question why
you don't validate slot.

> +
> + sdhci_get_of_property(pdev);
> +
> + pltfm_host->clk = devm_clk_get(&pdev->dev, NULL);
> + if (IS_ERR(pltfm_host->clk))
> + return PTR_ERR(pltfm_host->clk);
> +
> + ret = clk_prepare_enable(pltfm_host->clk);
> + if (ret) {
> + dev_err(&pdev->dev, "Unable to enable SDIO clock\n");
> + goto err_pltfm_free;
> + }
> +
> + ret = mmc_of_parse(host->mmc);
> + if (ret)
> + goto err_sdhci_add;
> +
> + ret = sdhci_add_host(host);
> + if (ret)
> + goto err_sdhci_add;
> +
> + return 0;
> +
> +err_sdhci_add:
> + clk_disable_unprepare(pltfm_host->clk);
> +err_pltfm_free:
> + sdhci_pltfm_free(pdev);
> + return ret;
> +}
> +
> +static int aspeed_sdhci_remove(struct platform_device *pdev)
> +{
> + struct sdhci_pltfm_host *pltfm_host;
> + struct sdhci_host *host;
> + int dead;
> +
> + host = platform_get_drvdata(pdev);
> + pltfm_host = sdhci_priv(host);
> +
> + dead = readl(host->ioaddr + SDHCI_INT_STATUS) == 0xffffffff;

'dead' only makes sense for PCI. Just set it to zero.

> +
> + sdhci_remove_host(host, dead);
> +
> + clk_disable_unprepare(pltfm_host->clk);
> +
> + sdhci_pltfm_free(pdev);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id aspeed_sdhci_of_match[] = {
> + { .compatible = "aspeed,ast2400-sdhci", },
> + { .compatible = "aspeed,ast2500-sdhci", },
> + { }
> +};
> +
> +static struct platform_driver aspeed_sdhci_driver = {
> + .driver = {
> + .name = "sdhci-aspeed",
> + .of_match_table = aspeed_sdhci_of_match,
> + },
> + .probe = aspeed_sdhci_probe,
> + .remove = aspeed_sdhci_remove,
> +};
> +
> +module_platform_driver(aspeed_sdhci_driver);
> +
> +static int aspeed_sdc_probe(struct platform_device *pdev)
> +
> +{
> + struct device_node *parent, *child;
> + struct aspeed_sdc *sdc;
> + int ret;
> +
> + sdc = devm_kzalloc(&pdev->dev, sizeof(*sdc), GFP_KERNEL);
> + if (!sdc)
> + return -ENOMEM;
> +
> + spin_lock_init(&sdc->lock);
> +
> + sdc->clk = devm_clk_get(&pdev->dev, NULL);
> + if (IS_ERR(sdc->clk))
> + return PTR_ERR(sdc->clk);
> +
> + ret = clk_prepare_enable(sdc->clk);
> + if (ret) {
> + dev_err(&pdev->dev, "Unable to enable SDCLK\n");
> + return ret;
> + }
> +
> + sdc->res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + sdc->regs = devm_ioremap_resource(&pdev->dev, sdc->res);
> + if (IS_ERR(sdc->regs)) {
> + ret = PTR_ERR(sdc->regs);
> + goto err_clk;
> + }
> +
> + dev_set_drvdata(&pdev->dev, sdc);
> +
> + parent = pdev->dev.of_node;
> + for_each_available_child_of_node(parent, child) {
> + struct platform_device *cpdev;
> +
> + cpdev = of_platform_device_create(child, NULL, &pdev->dev);
> + if (IS_ERR(cpdev)) {
> + of_node_put(child);
> + ret = PTR_ERR(pdev);
> + goto err_clk;
> + }
> + }
> +
> + return 0;
> +
> +err_clk:
> + clk_disable_unprepare(sdc->clk);
> + return ret;
> +}
> +
> +static int aspeed_sdc_remove(struct platform_device *pdev)
> +{
> + struct aspeed_sdc *sdc = dev_get_drvdata(&pdev->dev);
> +
> + clk_disable_unprepare(sdc->clk);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id aspeed_sdc_of_match[] = {
> + { .compatible = "aspeed,ast2400-sd-controller", },
> + { .compatible = "aspeed,ast2500-sd-controller", },
> + { }
> +};
> +
> +MODULE_DEVICE_TABLE(of, aspeed_sdc_of_match);
> +
> +static struct platform_driver aspeed_sdc_driver = {
> + .driver = {
> + .name = "sd-controller-aspeed",
> + .pm = &sdhci_pltfm_pmops,
> + .of_match_table = aspeed_sdc_of_match,
> + },
> + .probe = aspeed_sdc_probe,
> + .remove = aspeed_sdc_remove,
> +};
> +
> +module_platform_driver(aspeed_sdc_driver);
> +
> +MODULE_DESCRIPTION("Driver for the ASPEED SD/SDIO/SDHCI Controllers");
> +MODULE_AUTHOR("Ryan Chen <ryan_chen@aspeedtech.com>");
> +MODULE_AUTHOR("Andrew Jeffery <andrew@aj.id.au>");
> +MODULE_LICENSE("GPL v2");
>

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