Several phases can be controlled on the meson-gx controller, the core, tx
and rx clock phase. The tx and rx uses delays to allow for a more fine
grained setting of the phase. To properly compute the phase using delays,
accessing the clock rate is necessary.
Instead of ad-hoc functions, use the common clock framework to set the
clock phases (and access the clock rate while doing it).
Signed-off-by: Jerome Brunet <jbru...@baylibre.com>
---
drivers/mmc/host/meson-gx-mmc.c | 217 ++++++++++++++++++++++++++++++++--------
1 file changed, 176 insertions(+), 41 deletions(-)
diff --git a/drivers/mmc/host/meson-gx-mmc.c b/drivers/mmc/host/meson-gx-mmc.c
index 441ebf2b0146..df1ac96bd0db 100644
--- a/drivers/mmc/host/meson-gx-mmc.c
+++ b/drivers/mmc/host/meson-gx-mmc.c
@@ -46,10 +46,9 @@
#define CLK_CORE_PHASE_MASK GENMASK(9, 8)
#define CLK_TX_PHASE_MASK GENMASK(11, 10)
#define CLK_RX_PHASE_MASK GENMASK(13, 12)
-#define CLK_PHASE_0 0
-#define CLK_PHASE_90 1
-#define CLK_PHASE_180 2
-#define CLK_PHASE_270 3
+#define CLK_TX_DELAY_MASK GENMASK(19, 16)
+#define CLK_RX_DELAY_MASK GENMASK(23, 20)
+#define CLK_DELAY_STEP_PS 200
#define CLK_ALWAYS_ON BIT(24)
#define SD_EMMC_DELAY 0x4
@@ -121,9 +120,9 @@
#define MUX_CLK_NUM_PARENTS 2
struct meson_tuning_params {
- u8 core_phase;
- u8 tx_phase;
- u8 rx_phase;
+ unsigned int core_phase;
+ unsigned int tx_phase;
+ unsigned int rx_phase;
};
struct sd_emmc_desc {
@@ -142,6 +141,8 @@ struct meson_host {
void __iomem *regs;
struct clk *core_clk;
struct clk *mmc_clk;
+ struct clk *rx_clk;
+ struct clk *tx_clk;
unsigned long req_rate;
struct pinctrl *pinctrl;
@@ -181,6 +182,90 @@ struct meson_host {
#define CMD_RESP_MASK GENMASK(31, 1)
#define CMD_RESP_SRAM BIT(0)
+struct meson_mmc_phase {
+ struct clk_hw hw;
+ void __iomem *reg;
+ unsigned long phase_mask;
+ unsigned long delay_mask;
+ unsigned int delay_step_ps;
+};
+
+#define to_meson_mmc_phase(_hw) container_of(_hw, struct meson_mmc_phase, hw)
+
+static int meson_mmc_clk_get_phase(struct clk_hw *hw)
+{
+ struct meson_mmc_phase *mmc = to_meson_mmc_phase(hw);
+ unsigned int phase_num = 1 << hweight_long(mmc->phase_mask);
+ unsigned long period_ps, p, d;
+ int degrees;
+ u32 val;
+
+ val = readl(mmc->reg);
+ p = (val & mmc->phase_mask) >> __bf_shf(mmc->phase_mask);
+ degrees = p * 360 / phase_num;
+
+ if (mmc->delay_mask) {
+ period_ps = DIV_ROUND_UP((unsigned long)NSEC_PER_SEC * 1000,
+ clk_get_rate(hw->clk));
+ d = (val & mmc->delay_mask) >> __bf_shf(mmc->delay_mask);
+ degrees += d * mmc->delay_step_ps * 360 / period_ps;
+ degrees %= 360;
+ }
+
+ return degrees;
+}
+
+static void meson_mmc_apply_phase_delay(struct meson_mmc_phase *mmc,
+ unsigned int phase,
+ unsigned int delay)
+{
+ u32 val;
+
+ val = readl(mmc->reg);
+ val &= ~mmc->phase_mask;
+ val |= phase << __bf_shf(mmc->phase_mask);
+
+ if (mmc->delay_mask) {
+ val &= ~mmc->delay_mask;
+ val |= delay << __bf_shf(mmc->delay_mask);
+ }
+
+ writel(val, mmc->reg);
+}
+
+static int meson_mmc_clk_set_phase(struct clk_hw *hw, int degrees)
+{
+ struct meson_mmc_phase *mmc = to_meson_mmc_phase(hw);
+ unsigned int phase_num = 1 << hweight_long(mmc->phase_mask);
+ unsigned long period_ps, d = 0, r;
+ uint64_t p;
+
+ p = degrees % 360;
+
+ if (!mmc->delay_mask) {
+ p = DIV_ROUND_CLOSEST_ULL(p, 360 / phase_num);
+ } else {
+ period_ps = DIV_ROUND_UP((unsigned long)NSEC_PER_SEC * 1000,
+ clk_get_rate(hw->clk));
+
+ /* First compute the phase index (p), the remainder (r) is the
+ * part we'll try to acheive using the delays (d).
+ */
+ r = do_div(p, 360 / phase_num);
+ d = DIV_ROUND_CLOSEST(r * period_ps,
+ 360 * mmc->delay_step_ps);
+ d = min(d, mmc->delay_mask >> __bf_shf(mmc->delay_mask));
+ }
+
+ meson_mmc_apply_phase_delay(mmc, p, d);
+ return 0;
+}
+
+static const struct clk_ops meson_mmc_clk_phase_ops = {
+ .get_phase = meson_mmc_clk_get_phase,
+ .set_phase = meson_mmc_clk_set_phase,
+};
+
static unsigned int meson_mmc_get_timeout_msecs(struct mmc_data *data)
{
unsigned int timeout = data->timeout_ns / NSEC_PER_MSEC;
@@ -373,6 +458,13 @@ static int meson_mmc_clk_set(struct meson_host *host,
struct mmc_ios *ios)
return 0;
}
+static void meson_mmc_set_phase_params(struct meson_host *host)
+{
+ clk_set_phase(host->mmc_clk, host->tp.core_phase);
+ clk_set_phase(host->tx_clk, host->tp.tx_phase);
+ clk_set_phase(host->rx_clk, host->tp.rx_phase);
+}
+
/*
* The SD/eMMC IP block has an internal mux and divider used for
* generating the MMC clock. Use the clock framework to create and
@@ -383,6 +475,7 @@ static int meson_mmc_clk_init(struct meson_host *host)
struct clk_init_data init;
struct clk_mux *mux;
struct clk_divider *div;
+ struct meson_mmc_phase *core, *tx, *rx;
struct clk *clk;
char clk_name[32];
int i, ret = 0;
@@ -408,9 +501,6 @@ static int meson_mmc_clk_init(struct meson_host *host)
/* init SD_EMMC_CLOCK to sane defaults w/min clock rate */
clk_reg = 0;
- clk_reg |= FIELD_PREP(CLK_CORE_PHASE_MASK, host->tp.core_phase);
- clk_reg |= FIELD_PREP(CLK_TX_PHASE_MASK, host->tp.tx_phase);
- clk_reg |= FIELD_PREP(CLK_RX_PHASE_MASK, host->tp.rx_phase);
clk_reg |= CLK_DIV_MASK;
clk_reg |= CLK_ALWAYS_ON;
writel(clk_reg, host->regs + SD_EMMC_CLOCK);
@@ -456,10 +546,80 @@ static int meson_mmc_clk_init(struct meson_host *host)
div->flags = (CLK_DIVIDER_ONE_BASED |
CLK_DIVIDER_ROUND_CLOSEST);
- host->mmc_clk = devm_clk_register(host->dev, &div->hw);
+ clk = devm_clk_register(host->dev, &div->hw);
+ if (WARN_ON(IS_ERR(clk)))
+ return PTR_ERR(clk);
+
+ /* create the mmc core clock */
+ core = devm_kzalloc(host->dev, sizeof(*core), GFP_KERNEL);
+ if (!core)
+ return -ENOMEM;
+
+ snprintf(clk_name, sizeof(clk_name), "%s#core", dev_name(host->dev));
+ init.name = clk_name;
+ init.ops = &meson_mmc_clk_phase_ops;
+ init.flags = CLK_SET_RATE_PARENT;
+ clk_parent[0] = __clk_get_name(clk);
+ init.parent_names = clk_parent;
+ init.num_parents = 1;
+
+ core->reg = host->regs + SD_EMMC_CLOCK;
+ core->phase_mask = CLK_CORE_PHASE_MASK;
+ core->hw.init = &init;
+
+ host->mmc_clk = devm_clk_register(host->dev, &core->hw);
if (WARN_ON(PTR_ERR_OR_ZERO(host->mmc_clk)))
return PTR_ERR(host->mmc_clk);
+ /* create the mmc tx clock */
+ tx = devm_kzalloc(host->dev, sizeof(*tx), GFP_KERNEL);
+ if (!tx)
+ return -ENOMEM;
+
+ snprintf(clk_name, sizeof(clk_name), "%s#tx", dev_name(host->dev));
+ init.name = clk_name;
+ init.ops = &meson_mmc_clk_phase_ops;
+ init.flags = 0;
+ clk_parent[0] = __clk_get_name(host->mmc_clk);
+ init.parent_names = clk_parent;
+ init.num_parents = 1;
+
+ tx->reg = host->regs + SD_EMMC_CLOCK;
+ tx->phase_mask = CLK_TX_PHASE_MASK;
+ tx->delay_mask = CLK_TX_DELAY_MASK;
+ tx->delay_step_ps = CLK_DELAY_STEP_PS;
+ tx->hw.init = &init;
+
+ host->tx_clk = devm_clk_register(host->dev, &tx->hw);
+ if (WARN_ON(PTR_ERR_OR_ZERO(host->tx_clk)))
+ return PTR_ERR(host->tx_clk);
+
+ /* create the mmc rx clock */
+ rx = devm_kzalloc(host->dev, sizeof(*rx), GFP_KERNEL);
+ if (!rx)
+ return -ENOMEM;
+
+ snprintf(clk_name, sizeof(clk_name), "%s#rx", dev_name(host->dev));
+ init.name = clk_name;
+ init.ops = &meson_mmc_clk_phase_ops;
+ init.flags = 0;
+ clk_parent[0] = __clk_get_name(host->mmc_clk);
+ init.parent_names = clk_parent;
+ init.num_parents = 1;
+
+ rx->reg = host->regs + SD_EMMC_CLOCK;
+ rx->phase_mask = CLK_RX_PHASE_MASK;
+ rx->delay_mask = CLK_RX_DELAY_MASK;
+ rx->delay_step_ps = CLK_DELAY_STEP_PS;
+ rx->hw.init = &init;
+
+ host->rx_clk = devm_clk_register(host->dev, &rx->hw);
+ if (WARN_ON(PTR_ERR_OR_ZERO(host->rx_clk)))
+ return PTR_ERR(host->rx_clk);
+
+ /* Set the initial phase parameters */
+ meson_mmc_set_phase_params(host);
+
/* init SD_EMMC_CLOCK to sane defaults w/min clock rate */
host->mmc->f_min = clk_round_rate(host->mmc_clk, 400000);
ret = clk_set_rate(host->mmc_clk, host->mmc->f_min);
@@ -469,31 +629,6 @@ static int meson_mmc_clk_init(struct meson_host *host)
return clk_prepare_enable(host->mmc_clk);
}
-static void meson_mmc_set_tuning_params(struct mmc_host *mmc)
-{
- struct meson_host *host = mmc_priv(mmc);
- u32 regval;
-
- /* stop clock */
- regval = readl(host->regs + SD_EMMC_CFG);
- regval |= CFG_STOP_CLOCK;
- writel(regval, host->regs + SD_EMMC_CFG);
-
- regval = readl(host->regs + SD_EMMC_CLOCK);
- regval &= ~CLK_CORE_PHASE_MASK;
- regval |= FIELD_PREP(CLK_CORE_PHASE_MASK, host->tp.core_phase);
- regval &= ~CLK_TX_PHASE_MASK;
- regval |= FIELD_PREP(CLK_TX_PHASE_MASK, host->tp.tx_phase);
- regval &= ~CLK_RX_PHASE_MASK;
- regval |= FIELD_PREP(CLK_RX_PHASE_MASK, host->tp.rx_phase);
- writel(regval, host->regs + SD_EMMC_CLOCK);
-
- /* start clock */
- regval = readl(host->regs + SD_EMMC_CFG);
- regval &= ~CFG_STOP_CLOCK;
- writel(regval, host->regs + SD_EMMC_CFG);
-}
-
static void meson_mmc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
{
struct meson_host *host = mmc_priv(mmc);
@@ -863,13 +998,13 @@ static int meson_mmc_execute_tuning(struct mmc_host *mmc,
u32 opcode)
dev_info(mmc_dev(mmc), "(re)tuning...\n");
- for (i = CLK_PHASE_0; i <= CLK_PHASE_270; i++) {
+ for (i = 0; i < 360; i += 90) {
host->tp.rx_phase = i;
/* exclude the active parameter set if retuning */
if (!memcmp(&tp_old, &host->tp, sizeof(tp_old)) &&
mmc->doing_retune)
continue;
- meson_mmc_set_tuning_params(mmc);
+ meson_mmc_set_phase_params(host);
ret = mmc_send_tuning(mmc, opcode, &cmd_error);
if (!ret)
break;
@@ -1000,9 +1135,9 @@ static int meson_mmc_probe(struct platform_device *pdev)
if (ret)
goto free_host;
- host->tp.core_phase = CLK_PHASE_180;
- host->tp.tx_phase = CLK_PHASE_0;
- host->tp.rx_phase = CLK_PHASE_0;
+ host->tp.core_phase = 180;
+ host->tp.tx_phase = 0;
+ host->tp.rx_phase = 0;
ret = meson_mmc_clk_init(host);
if (ret)
--
2.9.5
