[PATCH 1/5] memory: ti-aemif: Create aemif_set_cs_timings()

[Bastien Curutchet]

Create an aemif_set_cs_timings() function to isolate the setting of a
chip select timing configuration and ease its exportation.
Move the check of the configuration validity from aemif_calc_rate() to
this new function.

Signed-off-by: Bastien Curutchet <bastien.curutchet at bootlin.com>
---
 drivers/memory/ti-aemif.c | 111 ++++++++++++++++++++++++++------------
 1 file changed, 78 insertions(+), 33 deletions(-)

diff --git a/drivers/memory/ti-aemif.c b/drivers/memory/ti-aemif.c
index d54dc3cfff73..5be6df246075 100644
--- a/drivers/memory/ti-aemif.c
+++ b/drivers/memory/ti-aemif.c
@@ -69,15 +69,15 @@
 #define ACR_SSTROBE_MASK	BIT(31)
 #define ASIZE_16BIT	1
 
-#define CONFIG_MASK	(TA(TA_MAX) | \
-				RHOLD(RHOLD_MAX) | \
-				RSTROBE(RSTROBE_MAX) |	\
-				RSETUP(RSETUP_MAX) | \
-				WHOLD(WHOLD_MAX) | \
-				WSTROBE(WSTROBE_MAX) | \
-				WSETUP(WSETUP_MAX) | \
-				EW(EW_MAX) | SSTROBE(SSTROBE_MAX) | \
-				ASIZE_MAX)
+#define TIMINGS_MASK	(TA(TA_MAX) | \
+			RHOLD(RHOLD_MAX) | \
+			RSTROBE(RSTROBE_MAX) |	\
+			RSETUP(RSETUP_MAX) | \
+			WHOLD(WHOLD_MAX) | \
+			WSTROBE(WSTROBE_MAX) | \
+			WSETUP(WSETUP_MAX))
+
+#define CONFIG_MASK	(EW(EW_MAX) | SSTROBE(SSTROBE_MAX) | ASIZE_MAX)
 
 /**
  * struct aemif_cs_data: structure to hold cs parameters
@@ -107,6 +107,27 @@ struct aemif_cs_data {
 	u8	asize;
 };
 
+/**
+ * struct aemif_cs_timing: structure to hold cs timing configuration
+ * values are expressed in number of clock cycles - 1
+ * @ta: minimum turn around time
+ * @rhold read hold width
+ * @rstrobe read strobe width
+ * @rsetup read setup width
+ * @whold write hold width
+ * @wstrobe write strobe width
+ * @wsetup write setup width
+ */
+struct aemif_cs_timings {
+	u32	ta;
+	u32	rhold;
+	u32	rstrobe;
+	u32	rsetup;
+	u32	whold;
+	u32	wstrobe;
+	u32	wsetup;
+};
+
 /**
  * struct aemif_device: structure to hold device data
  * @base: base address of AEMIF registers
@@ -125,6 +146,44 @@ struct aemif_device {
 	struct aemif_cs_data cs_data[NUM_CS];
 };
 
+/**
+ * aemif_set_cs_timings - Set the timing configuration of a given chip select.
+ * @aemif: aemif device to configure
+ * @cs: index of the chip select to configure.
+ * @timings: timings configuration to set
+ *
+ * Returns 0 on success, else negative errno.
+ */
+static int aemif_set_cs_timings(struct aemif_device *aemif, u8 cs, struct aemif_cs_timings *timings)
+{
+	unsigned int offset;
+	u32 val, set;
+
+	if (!timings || !aemif)
+		return -EINVAL;
+
+	if (cs > aemif->num_cs)
+		return -EINVAL;
+
+	if (timings->ta > TA_MAX || timings->rhold > RHOLD_MAX || timings->rstrobe > RSTROBE_MAX ||
+	    timings->rsetup > RSETUP_MAX || timings->whold > WHOLD_MAX ||
+	    timings->wstrobe > WSTROBE_MAX || timings->wsetup > WSETUP_MAX)
+		return -EINVAL;
+
+	set = TA(timings->ta) | RHOLD(timings->rhold) | RSTROBE(timings->rstrobe) |
+	      RSETUP(timings->rsetup) | WHOLD(timings->whold) |
+	      WSTROBE(timings->wstrobe) | WSETUP(timings->wsetup);
+
+	offset = A1CR_OFFSET + cs * 4;
+
+	val = readl(aemif->base + offset);
+	val &= ~TIMINGS_MASK;
+	val |= set;
+	writel(val, aemif->base + offset);
+
+	return 0;
+}
+
 /**
  * aemif_calc_rate - calculate timing data.
  * @pdev: platform device to calculate for
@@ -149,10 +208,6 @@ static int aemif_calc_rate(struct platform_device *pdev, int wanted,
 	if (result < 0)
 		result = 0;
 
-	/* ... But configuring tighter timings is not an option. */
-	else if (result > max)
-		result = -EINVAL;
-
 	return result;
 }
 
@@ -174,32 +229,22 @@ static int aemif_config_abus(struct platform_device *pdev, int csnum)
 {
 	struct aemif_device *aemif = platform_get_drvdata(pdev);
 	struct aemif_cs_data *data = &aemif->cs_data[csnum];
-	int ta, rhold, rstrobe, rsetup, whold, wstrobe, wsetup;
 	unsigned long clk_rate = aemif->clk_rate;
+	struct aemif_cs_timings timings;
 	unsigned offset;
 	u32 set, val;
 
 	offset = A1CR_OFFSET + (data->cs - aemif->cs_offset) * 4;
 
-	ta	= aemif_calc_rate(pdev, data->ta, clk_rate, TA_MAX);
-	rhold	= aemif_calc_rate(pdev, data->rhold, clk_rate, RHOLD_MAX);
-	rstrobe	= aemif_calc_rate(pdev, data->rstrobe, clk_rate, RSTROBE_MAX);
-	rsetup	= aemif_calc_rate(pdev, data->rsetup, clk_rate, RSETUP_MAX);
-	whold	= aemif_calc_rate(pdev, data->whold, clk_rate, WHOLD_MAX);
-	wstrobe	= aemif_calc_rate(pdev, data->wstrobe, clk_rate, WSTROBE_MAX);
-	wsetup	= aemif_calc_rate(pdev, data->wsetup, clk_rate, WSETUP_MAX);
-
-	if (ta < 0 || rhold < 0 || rstrobe < 0 || rsetup < 0 ||
-	    whold < 0 || wstrobe < 0 || wsetup < 0) {
-		dev_err(&pdev->dev, "%s: cannot get suitable timings\n",
-			__func__);
-		return -EINVAL;
-	}
-
-	set = TA(ta) | RHOLD(rhold) | RSTROBE(rstrobe) | RSETUP(rsetup) |
-		WHOLD(whold) | WSTROBE(wstrobe) | WSETUP(wsetup);
+	timings.ta = aemif_calc_rate(pdev, data->ta, clk_rate, TA_MAX);
+	timings.rhold = aemif_calc_rate(pdev, data->rhold, clk_rate, RHOLD_MAX);
+	timings.rstrobe = aemif_calc_rate(pdev, data->rstrobe, clk_rate, RSTROBE_MAX);
+	timings.rsetup = aemif_calc_rate(pdev, data->rsetup, clk_rate, RSETUP_MAX);
+	timings.whold = aemif_calc_rate(pdev, data->whold, clk_rate, WHOLD_MAX);
+	timings.wstrobe = aemif_calc_rate(pdev, data->wstrobe, clk_rate, WSTROBE_MAX);
+	timings.wsetup = aemif_calc_rate(pdev, data->wsetup, clk_rate, WSETUP_MAX);
 
-	set |= (data->asize & ACR_ASIZE_MASK);
+	set = (data->asize & ACR_ASIZE_MASK);
 	if (data->enable_ew)
 		set |= ACR_EW_MASK;
 	if (data->enable_ss)
@@ -210,7 +255,7 @@ static int aemif_config_abus(struct platform_device *pdev, int csnum)
 	val |= set;
 	writel(val, aemif->base + offset);
 
-	return 0;
+	return aemif_set_cs_timings(aemif, data->cs - aemif->cs_offset, &timings);
 }
 
 static inline int aemif_cycles_to_nsec(int val, unsigned long clk_rate)
-- 
2.47.0