The original clock support for MMC/SD cards on the RK3368 suffered from a tendency to select a divider less-or-equal to the the one giving the requested clock-rate: this can lead to higher-than-expected (or rather: higher than supported) clock rates for the MMC/SD communiction.
This change rewrites the MMC/SD clock generation to: * always generate a clock less-than-or-equal to the requested clock * support reparenting among the CPLL, GPLL and OSC24M parents to generate the highest clock that does not exceed the requested rate
In addition to this, the Linux DTS uses HCLK_MMC/HCLK_SDMMC instead of SCLK_MMC/SCLK_SDMMC: to match this (and to ensure that clock setup always works), we adjust the driver appropriately.
This includes the changes from: - rockchip: clk: rk3368: convert MMC_PLL_SEL_* definitions to shifted-value form
Signed-off-by: Philipp Tomsich philipp.tomsich@theobroma-systems.com ---
Changes in v2: None
arch/arm/include/asm/arch-rockchip/cru_rk3368.h | 8 +- drivers/clk/rockchip/clk_rk3368.c | 119 ++++++++++++++++++------ 2 files changed, 95 insertions(+), 32 deletions(-)
diff --git a/arch/arm/include/asm/arch-rockchip/cru_rk3368.h b/arch/arm/include/asm/arch-rockchip/cru_rk3368.h index bf09e2f..21f11e0 100644 --- a/arch/arm/include/asm/arch-rockchip/cru_rk3368.h +++ b/arch/arm/include/asm/arch-rockchip/cru_rk3368.h @@ -92,10 +92,10 @@ enum { /* CLKSEL51_CON */ MMC_PLL_SEL_SHIFT = 8, MMC_PLL_SEL_MASK = GENMASK(9, 8), - MMC_PLL_SEL_CPLL = 0, - MMC_PLL_SEL_GPLL, - MMC_PLL_SEL_USBPHY_480M, - MMC_PLL_SEL_24M, + MMC_PLL_SEL_CPLL = (0 << MMC_PLL_SEL_SHIFT), + MMC_PLL_SEL_GPLL = (1 << MMC_PLL_SEL_SHIFT), + MMC_PLL_SEL_USBPHY_480M = (2 << MMC_PLL_SEL_SHIFT), + MMC_PLL_SEL_24M = (3 << MMC_PLL_SEL_SHIFT), MMC_CLK_DIV_SHIFT = 0, MMC_CLK_DIV_MASK = GENMASK(6, 0),
diff --git a/drivers/clk/rockchip/clk_rk3368.c b/drivers/clk/rockchip/clk_rk3368.c index 33d2946..1327116 100644 --- a/drivers/clk/rockchip/clk_rk3368.c +++ b/drivers/clk/rockchip/clk_rk3368.c @@ -59,6 +59,8 @@ static const struct pll_div cpll_init_cfg = PLL_DIVISORS(CPLL_HZ, 1, 6); #endif #endif
+static ulong rk3368_clk_get_rate(struct clk *clk); + /* Get pll rate by id */ static uint32_t rkclk_pll_get_rate(struct rk3368_cru *cru, enum rk3368_pll_id pll_id) @@ -155,16 +157,17 @@ static void rkclk_init(struct rk3368_cru *cru) } #endif
+#if !IS_ENABLED(CONFIG_SPL_BUILD) || CONFIG_IS_ENABLED(MMC_SUPPORT) static ulong rk3368_mmc_get_clk(struct rk3368_cru *cru, uint clk_id) { u32 div, con, con_id, rate; u32 pll_rate;
switch (clk_id) { - case SCLK_SDMMC: + case HCLK_SDMMC: con_id = 50; break; - case SCLK_EMMC: + case HCLK_EMMC: con_id = 51; break; case SCLK_SDIO0: @@ -175,7 +178,7 @@ static ulong rk3368_mmc_get_clk(struct rk3368_cru *cru, uint clk_id) }
con = readl(&cru->clksel_con[con_id]); - switch ((con & MMC_PLL_SEL_MASK) >> MMC_PLL_SEL_SHIFT) { + switch (con & MMC_PLL_SEL_MASK) { case MMC_PLL_SEL_GPLL: pll_rate = rkclk_pll_get_rate(cru, GPLL); break; @@ -183,6 +186,8 @@ static ulong rk3368_mmc_get_clk(struct rk3368_cru *cru, uint clk_id) pll_rate = OSC_HZ; break; case MMC_PLL_SEL_CPLL: + pll_rate = rkclk_pll_get_rate(cru, CPLL); + break; case MMC_PLL_SEL_USBPHY_480M: default: return -EINVAL; @@ -190,23 +195,76 @@ static ulong rk3368_mmc_get_clk(struct rk3368_cru *cru, uint clk_id) div = (con & MMC_CLK_DIV_MASK) >> MMC_CLK_DIV_SHIFT; rate = DIV_TO_RATE(pll_rate, div);
+ debug("%s: raw rate %d (post-divide by 2)\n", __func__, rate); return rate >> 1; }
-static ulong rk3368_mmc_set_clk(struct rk3368_cru *cru, - ulong clk_id, ulong rate) +static ulong rk3368_mmc_find_best_rate_and_parent(struct clk *clk, + ulong rate, + u32 *best_mux, + u32 *best_div) +{ + int i; + ulong best_rate = 0; + const ulong MHz = 1000000; + const struct { + u32 mux; + ulong rate; + } parents[] = { + { .mux = MMC_PLL_SEL_CPLL, .rate = CPLL_HZ }, + { .mux = MMC_PLL_SEL_GPLL, .rate = GPLL_HZ }, + { .mux = MMC_PLL_SEL_24M, .rate = 24 * MHz } + }; + + debug("%s: target rate %ld\n", __func__, rate); + for (i = 0; i < ARRAY_SIZE(parents); ++i) { + /* + * Find the largest rate no larger than the target-rate for + * the current parent. + */ + ulong parent_rate = parents[i].rate; + u32 div = DIV_ROUND_UP(parent_rate, rate); + u32 adj_div = div; + ulong new_rate = parent_rate / adj_div; + + debug("%s: rate %ld, parent-mux %d, parent-rate %ld, div %d\n", + __func__, rate, parents[i].mux, parents[i].rate, div); + + /* Skip, if not representable */ + if ((div - 1) > MMC_CLK_DIV_MASK) + continue; + + /* Skip, if we already have a better (or equal) solution */ + if (new_rate <= best_rate) + continue; + + /* This is our new best rate. */ + best_rate = new_rate; + *best_mux = parents[i].mux; + *best_div = div - 1; + } + + debug("%s: best_mux = %x, best_div = %d, best_rate = %ld\n", + __func__, *best_mux, *best_div, best_rate); + + return best_rate; +} + +static ulong rk3368_mmc_set_clk(struct clk *clk, ulong rate) { - u32 div; - u32 con_id; - u32 gpll_rate = rkclk_pll_get_rate(cru, GPLL); + struct rk3368_clk_priv *priv = dev_get_priv(clk->dev); + struct rk3368_cru *cru = priv->cru; + ulong clk_id = clk->id; + u32 con_id, mux = 0, div = 0;
- div = RATE_TO_DIV(gpll_rate, rate << 1); + /* Find the best parent and rate */ + rk3368_mmc_find_best_rate_and_parent(clk, rate << 1, &mux, &div);
switch (clk_id) { - case SCLK_SDMMC: + case HCLK_SDMMC: con_id = 50; break; - case SCLK_EMMC: + case HCLK_EMMC: con_id = 51; break; case SCLK_SDIO0: @@ -216,33 +274,33 @@ static ulong rk3368_mmc_set_clk(struct rk3368_cru *cru, return -EINVAL; }
- if (div > 0x3f) { - div = RATE_TO_DIV(OSC_HZ, rate); - rk_clrsetreg(&cru->clksel_con[con_id], - MMC_PLL_SEL_MASK | MMC_CLK_DIV_MASK, - (MMC_PLL_SEL_24M << MMC_PLL_SEL_SHIFT) | - (div << MMC_CLK_DIV_SHIFT)); - } else { - rk_clrsetreg(&cru->clksel_con[con_id], - MMC_PLL_SEL_MASK | MMC_CLK_DIV_MASK, - (MMC_PLL_SEL_GPLL << MMC_PLL_SEL_SHIFT) | - div << MMC_CLK_DIV_SHIFT); - } + rk_clrsetreg(&cru->clksel_con[con_id], + MMC_PLL_SEL_MASK | MMC_CLK_DIV_MASK, + mux | div);
return rk3368_mmc_get_clk(cru, clk_id); } +#endif
static ulong rk3368_clk_get_rate(struct clk *clk) { struct rk3368_clk_priv *priv = dev_get_priv(clk->dev); ulong rate = 0;
- debug("%s id:%ld\n", __func__, clk->id); + debug("%s: id %ld\n", __func__, clk->id); switch (clk->id) { + case PLL_CPLL: + rate = rkclk_pll_get_rate(priv->cru, CPLL); + break; + case PLL_GPLL: + rate = rkclk_pll_get_rate(priv->cru, GPLL); + break; +#if !IS_ENABLED(CONFIG_SPL_BUILD) || CONFIG_IS_ENABLED(MMC_SUPPORT) case HCLK_SDMMC: case HCLK_EMMC: rate = rk3368_mmc_get_clk(priv->cru, clk->id); break; +#endif default: return -ENOENT; } @@ -291,10 +349,15 @@ static ulong rk3368_clk_set_rate(struct clk *clk, ulong rate) case CLK_DDR: ret = rk3368_ddr_set_clk(priv->cru, rate); break; - - case SCLK_SDMMC: - case SCLK_EMMC: - ret = rk3368_mmc_set_clk(priv->cru, clk->id, rate); +#if !IS_ENABLED(CONFIG_SPL_BUILD) || CONFIG_IS_ENABLED(MMC_SUPPORT) + case HCLK_SDMMC: + case HCLK_EMMC: + ret = rk3368_mmc_set_clk(clk, rate); + break; +#endif + case SCLK_MAC: + /* nothing to do, as this is an external clock */ + ret = rate; break; default: return -ENOENT;