[PATCH v3 1/2] MMC: meson: initial support for GXBB platforms

Ulf Hansson
2016-10-18T10:25:16Z

[...]

> +static int meson_mmc_clk_set(struct meson_host *host, unsigned long clk_rate)
> +{
> + struct mmc_host *mmc = host->mmc;
> + int ret = 0;
> + u32 cfg;
> +
> + if (clk_rate) {
> + if (WARN_ON(clk_rate > mmc->f_max))
> + clk_rate = mmc->f_max;
> + else if (WARN_ON(clk_rate < mmc->f_min))
> + clk_rate = mmc->f_min;
> + }
> +
> + if (clk_rate == mmc->actual_clock)
> + return 0;
> +
> + /* stop clock */
> + cfg = readl(host->regs + SD_EMMC_CFG);
> + if (!(cfg & CFG_STOP_CLOCK)) {
> + cfg |= CFG_STOP_CLOCK;
> + writel(cfg, host->regs + SD_EMMC_CFG);
> + }
> +
> + dev_dbg(host->dev, "change clock rate %u -> %lu\n",
> + mmc->actual_clock, clk_rate);
> + ret = clk_set_rate(host->cfg_div_clk, clk_rate);

Shouldn't you check the error before proceeding?

> + if (clk_rate && clk_rate != clk_get_rate(host->cfg_div_clk))
> + dev_warn(host->dev, "divider requested rate %lu != actual rate %lu: ret=%d\n",
> + clk_rate, clk_get_rate(host->cfg_div_clk), ret);
> + else
> + mmc->actual_clock = clk_rate;
> +
> + /* (re)start clock, if non-zero */
> + if (clk_rate) {
> + cfg = readl(host->regs + SD_EMMC_CFG);
> + cfg &= ~CFG_STOP_CLOCK;
> + writel(cfg, host->regs + SD_EMMC_CFG);
> + }
> +
> + return ret;
> +}
> +
> +/*
> + * The SD/eMMC IP block has an internal mux and divider used for
> + * generating the MMC clock. Use the clock framework to create and
> + * manage these clocks.
> + */
> +static int meson_mmc_clk_init(struct meson_host *host)
> +{
> + struct clk_init_data init;
> + char clk_name[32];
> + int i, ret = 0;
> + const char *mux_parent_names[MUX_CLK_NUM_PARENTS];
> + unsigned int mux_parent_count = 0;
> + const char *clk_div_parents[1];
> + unsigned int f_min = UINT_MAX;
> + u32 clk_reg, cfg;
> +
> + /* get the mux parents */
> + for (i = 0; i < MUX_CLK_NUM_PARENTS; i++) {
> + char name[16];
> +
> + snprintf(name, sizeof(name), "clkin%d", i);
> + host->mux_parent[i] = devm_clk_get(host->dev, name);
> + if (IS_ERR(host->mux_parent[i])) {
> + ret = PTR_ERR(host->mux_parent[i]);
> + if (PTR_ERR(host->mux_parent[i]) != -EPROBE_DEFER)
> + dev_err(host->dev, "Missing clock %s\n", name);
> + host->mux_parent[i] = NULL;
> + return ret;
> + }
> +
> + host->mux_parent_rate[i] = clk_get_rate(host->mux_parent[i]);
> + mux_parent_names[i] = __clk_get_name(host->mux_parent[i]);
> + mux_parent_count++;
> + if (host->mux_parent_rate[i] < f_min)
> + f_min = host->mux_parent_rate[i];
> + }
> +
> + /* cacluate f_min based on input clocks, and max divider value */
> + if (f_min != UINT_MAX)
> + f_min = DIV_ROUND_UP(CLK_SRC_XTAL_RATE, CLK_DIV_MAX);
> + else
> + f_min = 4000000; /* default min: 400 MHz */
> + host->mmc->f_min = f_min;
> +
> + /* create the mux */
> + snprintf(clk_name, sizeof(clk_name), "%s#mux", dev_name(host->dev));
> + init.name = clk_name;
> + init.ops = &clk_mux_ops;
> + init.flags = 0;
> + init.parent_names = mux_parent_names;
> + init.num_parents = mux_parent_count;
> +
> + host->mux.reg = host->regs + SD_EMMC_CLOCK;
> + host->mux.shift = CLK_SRC_SHIFT;
> + host->mux.mask = CLK_SRC_MASK;
> + host->mux.flags = 0;
> + host->mux.table = NULL;
> + host->mux.hw.init = &init;
> +
> + host->mux_clk = devm_clk_register(host->dev, &host->mux.hw);
> + if (WARN_ON(IS_ERR(host->mux_clk)))
> + return PTR_ERR(host->mux_clk);
> +
> + /* create the divider */
> + snprintf(clk_name, sizeof(clk_name), "%s#div", dev_name(host->dev));
> + init.name = devm_kstrdup(host->dev, clk_name, GFP_KERNEL);
> + init.ops = &clk_divider_ops;
> + init.flags = CLK_SET_RATE_PARENT;
> + clk_div_parents[0] = __clk_get_name(host->mux_clk);
> + init.parent_names = clk_div_parents;
> + init.num_parents = ARRAY_SIZE(clk_div_parents);
> +
> + host->cfg_div.reg = host->regs + SD_EMMC_CLOCK;
> + host->cfg_div.shift = CLK_DIV_SHIFT;
> + host->cfg_div.width = CLK_DIV_WIDTH;
> + host->cfg_div.hw.init = &init;
> + host->cfg_div.flags = CLK_DIVIDER_ONE_BASED |
> + CLK_DIVIDER_ROUND_CLOSEST | CLK_DIVIDER_ALLOW_ZERO;
> +
> + host->cfg_div_clk = devm_clk_register(host->dev, &host->cfg_div.hw);
> + if (WARN_ON(PTR_ERR_OR_ZERO(host->cfg_div_clk)))
> + return PTR_ERR(host->cfg_div_clk);
> +
> + /* init SD_EMMC_CLOCK to sane defaults w/min clock rate */
> + clk_reg = 0;
> + clk_reg |= CLK_PHASE_180 << CLK_PHASE_SHIFT;
> + clk_reg |= CLK_SRC_XTAL << CLK_SRC_SHIFT;
> + clk_reg |= CLK_DIV_MAX << CLK_DIV_SHIFT;
> + clk_reg &= ~CLK_ALWAYS_ON;
> + writel(clk_reg, host->regs + SD_EMMC_CLOCK);
> +
> + /* Ensure clock starts in "auto" mode, not "always on" */
> + cfg = readl(host->regs + SD_EMMC_CFG);
> + cfg &= ~CFG_CLK_ALWAYS_ON;
> + cfg |= CFG_AUTO_CLK;
> + writel(cfg, host->regs + SD_EMMC_CFG);
> +
> + ret = clk_prepare_enable(host->cfg_div_clk);
> + if (!ret)
> + ret = meson_mmc_clk_set(host, f_min);
> +

In case of errors, I guess you should disable/unprepare the clock.

> + return ret;
> +}
> +

[...]

> +
> +static int meson_mmc_probe(struct platform_device *pdev)
> +{
> + struct resource *res;
> + struct meson_host *host;
> + struct mmc_host *mmc;
> + int ret;
> +
> + mmc = mmc_alloc_host(sizeof(struct meson_host), &pdev->dev);
> + if (!mmc)
> + return -ENOMEM;
> + host = mmc_priv(mmc);
> + host->mmc = mmc;
> + host->dev = &pdev->dev;
> + dev_set_drvdata(&pdev->dev, host);
> +
> + spin_lock_init(&host->lock);
> +
> + host->core_clk = devm_clk_get(&pdev->dev, "core");
> + if (IS_ERR(host->core_clk)) {
> + ret = PTR_ERR(host->core_clk);
> + goto free_host;
> + }
> +
> + /* Get regulators and the supported OCR mask */
> + host->vqmmc_enabled = false;
> + ret = mmc_regulator_get_supply(mmc);
> + if (ret == -EPROBE_DEFER)
> + goto free_host;

In free_host you call clk_disable_unprepare(). You don't want to do
that unless you already called clk_prepare_enable().

So, I think you need another label to distinguish between these two cases.

> +
> + ret = mmc_of_parse(mmc);
> + if (ret) {
> + dev_warn(&pdev->dev, "error parsing DT: %d\n", ret);
> + goto free_host;
> + }
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + host->regs = devm_ioremap_resource(&pdev->dev, res);
> + if (IS_ERR(host->regs)) {
> + ret = PTR_ERR(host->regs);
> + goto free_host;
> + }
> +
> + host->irq = platform_get_irq(pdev, 0);
> + if (host->irq == 0) {
> + dev_err(&pdev->dev, "failed to get interrupt resource.\n");
> + ret = -EINVAL;
> + goto free_host;
> + }
> +
> + ret = clk_prepare_enable(host->core_clk);
> + if (ret)
> + goto free_host;
> +
> + ret = meson_mmc_clk_init(host);
> + if (ret)
> + goto free_host;
> +
> + /* Stop execution */
> + writel(0, host->regs + SD_EMMC_START);
> +
> + /* clear, ack, enable all interrupts */
> + writel(0, host->regs + SD_EMMC_IRQ_EN);
> + writel(IRQ_EN_MASK, host->regs + SD_EMMC_STATUS);
> +
> + ret = devm_request_threaded_irq(&pdev->dev, host->irq,
> + meson_mmc_irq, meson_mmc_irq_thread,
> + IRQF_SHARED, DRIVER_NAME, host);
> + if (ret)
> + goto free_host;

Besides the earlier issue mentiond for the label free_host, here you
also need to consider yet another clock that has be been enabled in
meson_mmc_clk_init(). I assume you want to disable this clock in the
error path.

> +
> + /* data bounce buffer */
> + host->bounce_buf_size = SZ_512K;
> + host->bounce_buf =
> + dma_alloc_coherent(host->dev, host->bounce_buf_size,
> + &host->bounce_dma_addr, GFP_KERNEL);
> + if (host->bounce_buf == NULL) {
> + dev_err(host->dev, "Unable to map allocate DMA bounce buffer.\n");
> + ret = -ENOMEM;
> + goto free_host;
> + }
> +
> + mmc->ops = &meson_mmc_ops;
> + mmc_add_host(mmc);
> +
> + return 0;
> +
> +free_host:
> + dev_dbg(host->dev, "Failed to probe: ret=%d\n", ret);

No need to print this, already managed by driver core.

> + if (host->core_clk)

No need to check above, already done by the clock framework.

> + clk_disable_unprepare(host->core_clk);
> + mmc_free_host(mmc);
> + return ret;
> +}
> +
> +static int meson_mmc_remove(struct platform_device *pdev)
> +{
> + struct meson_host *host = dev_get_drvdata(&pdev->dev);
> +
> + if (WARN_ON(!host))
> + return 0;
> +
> + if (host->bounce_buf)
> + dma_free_coherent(host->dev, host->bounce_buf_size,
> + host->bounce_buf, host->bounce_dma_addr);
> +
> + if (host->cfg_div_clk)

No need to check this, aleady done by the clock framework.

> + clk_disable_unprepare(host->cfg_div_clk);
> +
> + if (host->core_clk)

Ditto.

> + clk_disable_unprepare(host->core_clk);
> +
> + mmc_free_host(host->mmc);
> + return 0;
> +}
> +

[...]

Besides the minor stuff pointed out above, this looks great to me!

Before you re-spin, please drop this series from your branch which is
being integrated into linux-next, as otherwise I can't pick it up.

Kind regards
Uffe