In the the earlier change in this series ("Documentation: mmc: sdhci-of-arasan: Add soc-ctl-syscon for corecfg regs") we can see the mechansim for specifying a syscon to properly set corecfg registers in sdhci-of-arasan. Now let's use this mechanism to properly set corecfg_baseclkfreq on rk3399. >From [1] the corecfg_baseclkfreq is supposed to be set to: Base Clock Frequency for SD Clock. This is the frequency of the xin_clk. This is a relatively easy thing to do. Note that we assume that xin_clk is not dynamic and we can check the clock at probe time. If any real devices have a dynamic xin_clk future patches could register for notifiers for the clock. At the moment, setting corecfg_baseclkfreq is only supported for rk3399 since we need a specific map for each implementation. The code is written in a generic way that should make this easy to extend to other SoCs. Note that a specific compatible string for rk3399 is already in use and so we add that to the table to match rk3399. [1]: https://arasan.com/wp-content/media/eMMC-5-1-Total-Solution_Rev-1-3.pdf Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx> --- Changes in v2: - Reorder includes (Shawn) drivers/mmc/host/sdhci-of-arasan.c | 189 ++++++++++++++++++++++++++++++++++--- 1 file changed, 178 insertions(+), 11 deletions(-) diff --git a/drivers/mmc/host/sdhci-of-arasan.c b/drivers/mmc/host/sdhci-of-arasan.c index 3ff1711077c2..1286fe8905dc 100644 --- a/drivers/mmc/host/sdhci-of-arasan.c +++ b/drivers/mmc/host/sdhci-of-arasan.c @@ -19,9 +19,11 @@ * your option) any later version. */ +#include <linux/mfd/syscon.h> #include <linux/module.h> #include <linux/of_device.h> #include <linux/phy/phy.h> +#include <linux/regmap.h> #include "sdhci-pltfm.h" #define SDHCI_ARASAN_CLK_CTRL_OFFSET 0x2c @@ -32,18 +34,115 @@ #define CLK_CTRL_TIMEOUT_MASK (0xf << CLK_CTRL_TIMEOUT_SHIFT) #define CLK_CTRL_TIMEOUT_MIN_EXP 13 +/* + * On some SoCs the syscon area has a feature where the upper 16-bits of + * each 32-bit register act as a write mask for the lower 16-bits. This allows + * atomic updates of the register without locking. This macro is used on SoCs + * that have that feature. + */ +#define HIWORD_UPDATE(val, mask, shift) \ + ((val) << (shift) | (mask) << ((shift) + 16)) + +/** + * struct sdhci_arasan_soc_ctl_field - Field used in sdhci_arasan_soc_ctl_map + * + * @reg: Offset within the syscon of the register containing this field + * @width: Number of bits for this field + * @shift: Bit offset within @reg of this field (or -1 if not avail) + */ +struct sdhci_arasan_soc_ctl_field { + u32 reg; + u16 width; + s16 shift; +}; + +/** + * struct sdhci_arasan_soc_ctl_map - Map in syscon to corecfg registers + * + * It's up to the licensee of the Arsan IP block to make these available + * somewhere if needed. Presumably these will be scattered somewhere that's + * accessible via the syscon API. + * + * @baseclkfreq: Where to find corecfg_baseclkfreq + * @hiword_update: If true, use HIWORD_UPDATE to access the syscon + */ +struct sdhci_arasan_soc_ctl_map { + struct sdhci_arasan_soc_ctl_field baseclkfreq; + bool hiword_update; +}; + /** * struct sdhci_arasan_data - * @clk_ahb: Pointer to the AHB clock - * @phy: Pointer to the generic phy - * @phy_on: True if the PHY is turned on. + * @clk_ahb: Pointer to the AHB clock + * @phy: Pointer to the generic phy + * @phy_on: True if the PHY is turned on. + * @soc_ctl_base: Pointer to regmap for syscon for soc_ctl registers. + * @soc_ctl_map: Map to get offsets into soc_ctl registers. */ struct sdhci_arasan_data { struct clk *clk_ahb; struct phy *phy; bool phy_on; + + struct regmap *soc_ctl_base; + const struct sdhci_arasan_soc_ctl_map *soc_ctl_map; +}; + +static const struct sdhci_arasan_soc_ctl_map rk3399_soc_ctl_map = { + .baseclkfreq = { .reg = 0xf000, .width = 8, .shift = 8 }, + .hiword_update = true, }; +/** + * sdhci_arasan_syscon_write - Write to a field in soc_ctl registers + * + * This function allows writing to fields in sdhci_arasan_soc_ctl_map. + * Note that if a field is specified as not available (shift < 0) then + * this function will silently return an error code. It will be noisy + * and print errors for any other (unexpected) errors. + * + * @host: The sdhci_host + * @fld: The field to write to + * @val: The value to write + */ +static int sdhci_arasan_syscon_write(struct sdhci_host *host, + const struct sdhci_arasan_soc_ctl_field *fld, + u32 val) +{ + struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host); + struct sdhci_arasan_data *sdhci_arasan = sdhci_pltfm_priv(pltfm_host); + struct regmap *soc_ctl_base = sdhci_arasan->soc_ctl_base; + u32 reg = fld->reg; + u16 width = fld->width; + s16 shift = fld->shift; + int ret; + + /* + * Silently return errors for shift < 0 so caller doesn't have + * to check for fields which are optional. For fields that + * are required then caller needs to do something special + * anyway. + */ + if (shift < 0) + return -EINVAL; + + if (sdhci_arasan->soc_ctl_map->hiword_update) + ret = regmap_write(soc_ctl_base, reg, + HIWORD_UPDATE(val, GENMASK(width, 0), + shift)); + else + ret = regmap_update_bits(soc_ctl_base, reg, + GENMASK(shift + width, shift), + val << shift); + + /* Yell about (unexpected) regmap errors */ + if (ret) + pr_warn("%s: Regmap write fail: %d\n", + mmc_hostname(host->mmc), ret); + + return ret; +} + static unsigned int sdhci_arasan_get_timeout_clock(struct sdhci_host *host) { u32 div; @@ -191,9 +290,66 @@ static int sdhci_arasan_resume(struct device *dev) static SIMPLE_DEV_PM_OPS(sdhci_arasan_dev_pm_ops, sdhci_arasan_suspend, sdhci_arasan_resume); +static const struct of_device_id sdhci_arasan_of_match[] = { + /* SoC-specific compatible strings w/ soc_ctl_map */ + { + .compatible = "rockchip,rk3399-sdhci-5.1", + .data = &rk3399_soc_ctl_map, + }, + + /* Generic compatible below here */ + { .compatible = "arasan,sdhci-8.9a" }, + { .compatible = "arasan,sdhci-5.1" }, + { .compatible = "arasan,sdhci-4.9a" }, + + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(of, sdhci_arasan_of_match); + +/** + * sdhci_arasan_update_baseclkfreq - Set corecfg_baseclkfreq + * + * The corecfg_baseclkfreq is supposed to contain the MHz of clk_xin. This + * function can be used to make that happen. + * + * NOTES: + * - Many existing devices don't seem to do this and work fine. To keep + * compatibility for old hardware where the device tree doesn't provide a + * register map, this function is a noop if a soc_ctl_map hasn't been provided + * for this platform. + * - It's assumed that clk_xin is not dynamic and that we use the SDHCI divider + * to achieve lower clock rates. That means that this function is called once + * at probe time and never called again. + * + * @host: The sdhci_host + */ +static void sdhci_arasan_update_baseclkfreq(struct sdhci_host *host) +{ + struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host); + struct sdhci_arasan_data *sdhci_arasan = sdhci_pltfm_priv(pltfm_host); + const struct sdhci_arasan_soc_ctl_map *soc_ctl_map = + sdhci_arasan->soc_ctl_map; + u32 mhz = DIV_ROUND_CLOSEST(clk_get_rate(pltfm_host->clk), 1000000); + + /* Having a map is optional */ + if (!soc_ctl_map) + return; + + /* If we have a map, we expect to have a syscon */ + if (!sdhci_arasan->soc_ctl_base) { + pr_warn("%s: Have regmap, but no soc-ctl-syscon\n", + mmc_hostname(host->mmc)); + return; + } + + sdhci_arasan_syscon_write(host, &soc_ctl_map->baseclkfreq, mhz); +} + static int sdhci_arasan_probe(struct platform_device *pdev) { int ret; + const struct of_device_id *match; + struct device_node *node; struct clk *clk_xin; struct sdhci_host *host; struct sdhci_pltfm_host *pltfm_host; @@ -207,6 +363,23 @@ static int sdhci_arasan_probe(struct platform_device *pdev) pltfm_host = sdhci_priv(host); sdhci_arasan = sdhci_pltfm_priv(pltfm_host); + match = of_match_node(sdhci_arasan_of_match, pdev->dev.of_node); + sdhci_arasan->soc_ctl_map = match->data; + + node = of_parse_phandle(pdev->dev.of_node, "arasan,soc-ctl-syscon", 0); + if (node) { + sdhci_arasan->soc_ctl_base = syscon_node_to_regmap(node); + of_node_put(node); + + if (IS_ERR(sdhci_arasan->soc_ctl_base)) { + ret = PTR_ERR(sdhci_arasan->soc_ctl_base); + if (ret != -EPROBE_DEFER) + dev_err(&pdev->dev, "Can't get syscon: %d\n", + ret); + goto err_pltfm_free; + } + } + sdhci_arasan->clk_ahb = devm_clk_get(&pdev->dev, "clk_ahb"); if (IS_ERR(sdhci_arasan->clk_ahb)) { dev_err(&pdev->dev, "clk_ahb clock not found.\n"); @@ -236,6 +409,8 @@ static int sdhci_arasan_probe(struct platform_device *pdev) sdhci_get_of_property(pdev); pltfm_host->clk = clk_xin; + sdhci_arasan_update_baseclkfreq(host); + ret = mmc_of_parse(host->mmc); if (ret) { dev_err(&pdev->dev, "parsing dt failed (%u)\n", ret); @@ -301,14 +476,6 @@ static int sdhci_arasan_remove(struct platform_device *pdev) return ret; } -static const struct of_device_id sdhci_arasan_of_match[] = { - { .compatible = "arasan,sdhci-8.9a" }, - { .compatible = "arasan,sdhci-5.1" }, - { .compatible = "arasan,sdhci-4.9a" }, - { } -}; -MODULE_DEVICE_TABLE(of, sdhci_arasan_of_match); - static struct platform_driver sdhci_arasan_driver = { .driver = { .name = "sdhci-arasan", -- 2.8.0.rc3.226.g39d4020 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html