Merge tag 'memory-controller-drv-ti-6.14' of https://git.kernel.org/pub/scm/linux/kernel/git/krzk/linux-mem-ctrl into soc/drivers

Memory controller drivers for v6.14 - TI

TI AEMIF driver enhancements: some refactoring around timing
parameters and finally adding plus exporting interfaces for devices
using the AEMIF interface (e.g. TI Davinci NAND controller) to better
configure the memory interface.

The exported functions are going to be used by:
drivers/mtd/nand/raw/davinci_nand.c

* tag 'memory-controller-drv-ti-6.14' of https://git.kernel.org/pub/scm/linux/kernel/git/krzk/linux-mem-ctrl:
  memory: ti-aemif: Export aemif_*_cs_timings()
  memory: ti-aemif: Create aemif_set_cs_timings()
  memory: ti-aemif: Create aemif_check_cs_timings()
  memory: ti-aemif: Wrap CS timings into a struct
  memory: ti-aemif: Remove unnecessary local variables
  memory: ti-aemif: Store timings parameter in number of cycles - 1

Link: https://lore.kernel.org/r/20241231133534.136771-2-krzysztof.kozlowski@linaro.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

2 files changed, 148 insertions, 76 deletions

diff --git a/drivers/memory/ti-aemif.c b/drivers/memory/ti-aemif.c
index d54dc3cfff73..c8b83c9edbd5 100644
--- a/drivers/memory/ti-aemif.c
+++ b/drivers/memory/ti-aemif.c
@@ -13,7 +13,9 @@
 #include <linux/err.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
+#include <linux/memory/ti-aemif.h>
 #include <linux/module.h>
+#include <linux/mutex.h>
 #include <linux/of.h>
 #include <linux/of_platform.h>
 #include <linux/platform_device.h>
@@ -69,39 +71,27 @@
 #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
+ * struct aemif_cs_data: structure to hold CS parameters
+ * @timings: timings configuration
  * @cs: chip-select number
- * @wstrobe: write strobe width, ns
- * @rstrobe: read strobe width, ns
- * @wsetup: write setup width, ns
- * @whold: write hold width, ns
- * @rsetup: read setup width, ns
- * @rhold: read hold width, ns
- * @ta: minimum turn around time, ns
  * @enable_ss: enable/disable select strobe mode
  * @enable_ew: enable/disable extended wait mode
  * @asize: width of the asynchronous device's data bus
  */
 struct aemif_cs_data {
+	struct aemif_cs_timings timings;
 	u8	cs;
-	u16	wstrobe;
-	u16	rstrobe;
-	u8	wsetup;
-	u8	whold;
-	u8	rsetup;
-	u8	rhold;
-	u8	ta;
 	u8	enable_ss;
 	u8	enable_ew;
 	u8	asize;
@@ -115,6 +105,7 @@ struct aemif_cs_data {
  * @num_cs: number of assigned chip-selects
  * @cs_offset: start number of cs nodes
  * @cs_data: array of chip-select settings
+ * @config_cs_lock: lock used to access CS configuration
  */
 struct aemif_device {
 	void __iomem *base;
@@ -123,20 +114,94 @@ struct aemif_device {
 	u8 num_cs;
 	int cs_offset;
 	struct aemif_cs_data cs_data[NUM_CS];
+	struct mutex config_cs_lock;
 };
 
 /**
+ * aemif_check_cs_timings() - Check the validity of a CS timing configuration.
+ * @timings: timings configuration
+ *
+ * @return: 0 if the timing configuration is valid, negative error number otherwise.
+ */
+int aemif_check_cs_timings(struct aemif_cs_timings *timings)
+{
+	if (timings->ta > TA_MAX)
+		return -EINVAL;
+
+	if (timings->rhold > RHOLD_MAX)
+		return -EINVAL;
+
+	if (timings->rstrobe > RSTROBE_MAX)
+		return -EINVAL;
+
+	if (timings->rsetup > RSETUP_MAX)
+		return -EINVAL;
+
+	if (timings->whold > WHOLD_MAX)
+		return -EINVAL;
+
+	if (timings->wstrobe > WSTROBE_MAX)
+		return -EINVAL;
+
+	if (timings->wsetup > WSETUP_MAX)
+		return -EINVAL;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(aemif_check_cs_timings);
+
+/**
+ * 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
+ *
+ * @return: 0 on success, else negative errno.
+ */
+int aemif_set_cs_timings(struct aemif_device *aemif, u8 cs,
+			 struct aemif_cs_timings *timings)
+{
+	unsigned int offset;
+	u32 val, set;
+	int ret;
+
+	if (!timings || !aemif)
+		return -EINVAL;
+
+	if (cs > aemif->num_cs)
+		return -EINVAL;
+
+	ret = aemif_check_cs_timings(timings);
+	if (ret)
+		return ret;
+
+	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;
+
+	mutex_lock(&aemif->config_cs_lock);
+	val = readl(aemif->base + offset);
+	val &= ~TIMINGS_MASK;
+	val |= set;
+	writel(val, aemif->base + offset);
+	mutex_unlock(&aemif->config_cs_lock);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(aemif_set_cs_timings);
+
+/**
  * aemif_calc_rate - calculate timing data.
  * @pdev: platform device to calculate for
  * @wanted: The cycle time needed in nanoseconds.
  * @clk: The input clock rate in kHz.
- * @max: The maximum divider value that can be programmed.
  *
- * On success, returns the calculated timing value minus 1 for easy
- * programming into AEMIF timing registers, else negative errno.
+ * @return: the calculated timing value minus 1 for easy
+ * programming into AEMIF timing registers.
  */
-static int aemif_calc_rate(struct platform_device *pdev, int wanted,
-			   unsigned long clk, int max)
+static u32 aemif_calc_rate(struct platform_device *pdev, int wanted, unsigned long clk)
 {
 	int result;
 
@@ -149,10 +214,6 @@ 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;
 }
 
@@ -174,48 +235,25 @@ 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;
 	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);
-
-	set |= (data->asize & ACR_ASIZE_MASK);
+	set = (data->asize & ACR_ASIZE_MASK);
 	if (data->enable_ew)
 		set |= ACR_EW_MASK;
 	if (data->enable_ss)
 		set |= ACR_SSTROBE_MASK;
 
+	mutex_lock(&aemif->config_cs_lock);
 	val = readl(aemif->base + offset);
 	val &= ~CONFIG_MASK;
 	val |= set;
 	writel(val, aemif->base + offset);
+	mutex_unlock(&aemif->config_cs_lock);
 
-	return 0;
-}
-
-static inline int aemif_cycles_to_nsec(int val, unsigned long clk_rate)
-{
-	return ((val + 1) * NSEC_PER_MSEC) / clk_rate;
+	return aemif_set_cs_timings(aemif, data->cs - aemif->cs_offset, &data->timings);
 }
 
 /**
@@ -231,19 +269,18 @@ static void aemif_get_hw_params(struct platform_device *pdev, int csnum)
 {
 	struct aemif_device *aemif = platform_get_drvdata(pdev);
 	struct aemif_cs_data *data = &aemif->cs_data[csnum];
-	unsigned long clk_rate = aemif->clk_rate;
 	u32 val, offset;
 
 	offset = A1CR_OFFSET + (data->cs - aemif->cs_offset) * 4;
 	val = readl(aemif->base + offset);
 
-	data->ta = aemif_cycles_to_nsec(TA_VAL(val), clk_rate);
-	data->rhold = aemif_cycles_to_nsec(RHOLD_VAL(val), clk_rate);
-	data->rstrobe = aemif_cycles_to_nsec(RSTROBE_VAL(val), clk_rate);
-	data->rsetup = aemif_cycles_to_nsec(RSETUP_VAL(val), clk_rate);
-	data->whold = aemif_cycles_to_nsec(WHOLD_VAL(val), clk_rate);
-	data->wstrobe = aemif_cycles_to_nsec(WSTROBE_VAL(val), clk_rate);
-	data->wsetup = aemif_cycles_to_nsec(WSETUP_VAL(val), clk_rate);
+	data->timings.ta = TA_VAL(val);
+	data->timings.rhold = RHOLD_VAL(val);
+	data->timings.rstrobe = RSTROBE_VAL(val);
+	data->timings.rsetup = RSETUP_VAL(val);
+	data->timings.whold = WHOLD_VAL(val);
+	data->timings.wstrobe = WSTROBE_VAL(val);
+	data->timings.wsetup = WSETUP_VAL(val);
 	data->enable_ew = EW_VAL(val);
 	data->enable_ss = SSTROBE_VAL(val);
 	data->asize = val & ASIZE_MAX;
@@ -261,6 +298,7 @@ static int of_aemif_parse_abus_config(struct platform_device *pdev,
 				      struct device_node *np)
 {
 	struct aemif_device *aemif = platform_get_drvdata(pdev);
+	unsigned long clk_rate = aemif->clk_rate;
 	struct aemif_cs_data *data;
 	u32 cs;
 	u32 val;
@@ -288,32 +326,33 @@ static int of_aemif_parse_abus_config(struct platform_device *pdev,
 
 	/* override the values from device node */
 	if (!of_property_read_u32(np, "ti,cs-min-turnaround-ns", &val))
-		data->ta = val;
+		data->timings.ta = aemif_calc_rate(pdev, val, clk_rate);
 
 	if (!of_property_read_u32(np, "ti,cs-read-hold-ns", &val))
-		data->rhold = val;
+		data->timings.rhold = aemif_calc_rate(pdev, val, clk_rate);
 
 	if (!of_property_read_u32(np, "ti,cs-read-strobe-ns", &val))
-		data->rstrobe = val;
+		data->timings.rstrobe = aemif_calc_rate(pdev, val, clk_rate);
 
 	if (!of_property_read_u32(np, "ti,cs-read-setup-ns", &val))
-		data->rsetup = val;
+		data->timings.rsetup = aemif_calc_rate(pdev, val, clk_rate);
 
 	if (!of_property_read_u32(np, "ti,cs-write-hold-ns", &val))
-		data->whold = val;
+		data->timings.whold = aemif_calc_rate(pdev, val, clk_rate);
 
 	if (!of_property_read_u32(np, "ti,cs-write-strobe-ns", &val))
-		data->wstrobe = val;
+		data->timings.wstrobe = aemif_calc_rate(pdev, val, clk_rate);
 
 	if (!of_property_read_u32(np, "ti,cs-write-setup-ns", &val))
-		data->wsetup = val;
+		data->timings.wsetup = aemif_calc_rate(pdev, val, clk_rate);
 
 	if (!of_property_read_u32(np, "ti,cs-bus-width", &val))
 		if (val == 16)
 			data->asize = 1;
 	data->enable_ew = of_property_read_bool(np, "ti,cs-extended-wait-mode");
 	data->enable_ss = of_property_read_bool(np, "ti,cs-select-strobe-mode");
-	return 0;
+
+	return aemif_check_cs_timings(&data->timings);
 }
 
 static const struct of_device_id aemif_of_match[] = {
@@ -351,6 +390,7 @@ static int aemif_probe(struct platform_device *pdev)
 	if (IS_ERR(aemif->base))
 		return PTR_ERR(aemif->base);
 
+	mutex_init(&aemif->config_cs_lock);
 	if (np) {
 		/*
 		 * For every controller device node, there is a cs device node
diff --git a/include/linux/memory/ti-aemif.h b/include/linux/memory/ti-aemif.h
new file mode 100644
index 000000000000..da94a9d985e7
--- /dev/null
+++ b/include/linux/memory/ti-aemif.h
@@ -0,0 +1,32 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef __MEMORY_TI_AEMIF_H
+#define __MEMORY_TI_AEMIF_H
+
+/**
+ * struct aemif_cs_timings: 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;
+
+int aemif_set_cs_timings(struct aemif_device *aemif, u8 cs, struct aemif_cs_timings *timings);
+int aemif_check_cs_timings(struct aemif_cs_timings *timings);
+
+#endif // __MEMORY_TI_AEMIF_H