Export the aemif_set_cs_timing() symbol so it can be used by other
drivers

Add a spinlock to protect the CS configuration register from concurrent
accesses.

Signed-off-by: Bastien Curutchet <bastien.curutchet@bootlin.com>
---
 drivers/memory/ti-aemif.c | 35 +++++++++++++----------------------
 include/memory/ti-aemif.h | 31 +++++++++++++++++++++++++++++++
 2 files changed, 44 insertions(+), 22 deletions(-)
 create mode 100644 include/memory/ti-aemif.h

diff --git a/drivers/memory/ti-aemif.c b/drivers/memory/ti-aemif.c
index 5be6df246075..ee857c16a02c 100644
--- a/drivers/memory/ti-aemif.c
+++ b/drivers/memory/ti-aemif.c
@@ -17,6 +17,8 @@
 #include <linux/of.h>
 #include <linux/of_platform.h>
 #include <linux/platform_device.h>
+#include <linux/spinlock.h>
+#include <memory/ti-aemif.h>
 
 #define TA_SHIFT	2
 #define RHOLD_SHIFT	4
@@ -107,27 +109,6 @@ 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
@@ -136,6 +117,7 @@ struct aemif_cs_timings {
  * @num_cs: number of assigned chip-selects
  * @cs_offset: start number of cs nodes
  * @cs_data: array of chip-select settings
+ * @cs_config_lock: lock used to access CS configuration
  */
 struct aemif_device {
 	void __iomem *base;
@@ -144,6 +126,7 @@ struct aemif_device {
 	u8 num_cs;
 	int cs_offset;
 	struct aemif_cs_data cs_data[NUM_CS];
+	spinlock_t config_cs_lock;
 };
 
 /**
@@ -154,8 +137,9 @@ struct aemif_device {
  *
  * Returns 0 on success, else negative errno.
  */
-static int aemif_set_cs_timings(struct aemif_device *aemif, u8 cs, struct aemif_cs_timings *timings)
+int aemif_set_cs_timings(struct aemif_device *aemif, u8 cs, struct aemif_cs_timings *timings)
 {
+	unsigned long flags;
 	unsigned int offset;
 	u32 val, set;
 
@@ -176,13 +160,16 @@ static int aemif_set_cs_timings(struct aemif_device *aemif, u8 cs, struct aemif_
 
 	offset = A1CR_OFFSET + cs * 4;
 
+	spin_lock_irqsave(&aemif->config_cs_lock, flags);
 	val = readl(aemif->base + offset);
 	val &= ~TIMINGS_MASK;
 	val |= set;
 	writel(val, aemif->base + offset);
+	spin_unlock_irqrestore(&aemif->config_cs_lock, flags);
 
 	return 0;
 }
+EXPORT_SYMBOL(aemif_set_cs_timings);
 
 /**
  * aemif_calc_rate - calculate timing data.
@@ -231,6 +218,7 @@ static int aemif_config_abus(struct platform_device *pdev, int csnum)
 	struct aemif_cs_data *data = &aemif->cs_data[csnum];
 	unsigned long clk_rate = aemif->clk_rate;
 	struct aemif_cs_timings timings;
+	unsigned long flags;
 	unsigned offset;
 	u32 set, val;
 
@@ -250,10 +238,12 @@ static int aemif_config_abus(struct platform_device *pdev, int csnum)
 	if (data->enable_ss)
 		set |= ACR_SSTROBE_MASK;
 
+	spin_lock_irqsave(&aemif->config_cs_lock, flags);
 	val = readl(aemif->base + offset);
 	val &= ~CONFIG_MASK;
 	val |= set;
 	writel(val, aemif->base + offset);
+	spin_unlock_irqrestore(&aemif->config_cs_lock, flags);
 
 	return aemif_set_cs_timings(aemif, data->cs - aemif->cs_offset, &timings);
 }
@@ -396,6 +386,7 @@ static int aemif_probe(struct platform_device *pdev)
 	if (IS_ERR(aemif->base))
 		return PTR_ERR(aemif->base);
 
+	spin_lock_init(&aemif->config_cs_lock);
 	if (np) {
 		/*
 		 * For every controller device node, there is a cs device node
diff --git a/include/memory/ti-aemif.h b/include/memory/ti-aemif.h
new file mode 100644
index 000000000000..a1478387a8d0
--- /dev/null
+++ b/include/memory/ti-aemif.h
@@ -0,0 +1,31 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef __TI_AEMIF_H
+#define __TI_AEMIF_H
+
+/**
+ * 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;
+
+int aemif_set_cs_timings(struct aemif_device *aemif, u8 cs, struct aemif_cs_timings *timings);
+
+#endif // __TI_AEMIF_H
-- 
2.47.0

Hi Bastien,

kernel test robot noticed the following build warnings:

[auto build test WARNING on krzk-mem-ctrl/for-next]
[also build test WARNING on mtd/nand/next linus/master v6.12-rc5 next-20241030]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Bastien-Curutchet/memory-ti-aemif-Create-aemif_set_cs_timings/20241030-184949
base:   https://git.kernel.org/pub/scm/linux/kernel/git/krzk/linux-mem-ctrl.git for-next
patch link:    https://lore.kernel.org/r/20241030104717.88688-3-bastien.curutchet%40bootlin.com
patch subject: [PATCH 2/5] memory: ti-aemif: export aemif_set_cs_timing()
config: arc-randconfig-001-20241031 (https://download.01.org/0day-ci/archive/20241031/202410311304.0fuqFK2M-lkp@intel.com/config)
compiler: arc-elf-gcc (GCC) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241031/202410311304.0fuqFK2M-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202410311304.0fuqFK2M-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> drivers/memory/ti-aemif.c:130: warning: Function parameter or struct member 'config_cs_lock' not described in 'aemif_device'
>> drivers/memory/ti-aemif.c:130: warning: Excess struct member 'cs_config_lock' description in 'aemif_device'

Kconfig warnings: (for reference only)
   WARNING: unmet direct dependencies detected for GET_FREE_REGION
   Depends on [n]: SPARSEMEM [=n]
   Selected by [m]:
   - RESOURCE_KUNIT_TEST [=m] && RUNTIME_TESTING_MENU [=y] && KUNIT [=m]


vim +130 drivers/memory/ti-aemif.c

5a7c81547c1db75 Ivan Khoronzhuk   2014-02-24  111  
5a7c81547c1db75 Ivan Khoronzhuk   2014-02-24  112  /**
5a7c81547c1db75 Ivan Khoronzhuk   2014-02-24  113   * struct aemif_device: structure to hold device data
5a7c81547c1db75 Ivan Khoronzhuk   2014-02-24  114   * @base: base address of AEMIF registers
5a7c81547c1db75 Ivan Khoronzhuk   2014-02-24  115   * @clk: source clock
5a7c81547c1db75 Ivan Khoronzhuk   2014-02-24  116   * @clk_rate: clock's rate in kHz
5a7c81547c1db75 Ivan Khoronzhuk   2014-02-24  117   * @num_cs: number of assigned chip-selects
5a7c81547c1db75 Ivan Khoronzhuk   2014-02-24  118   * @cs_offset: start number of cs nodes
5a7c81547c1db75 Ivan Khoronzhuk   2014-02-24  119   * @cs_data: array of chip-select settings
0f034c3604121bf Bastien Curutchet 2024-10-30  120   * @cs_config_lock: lock used to access CS configuration
5a7c81547c1db75 Ivan Khoronzhuk   2014-02-24  121   */
5a7c81547c1db75 Ivan Khoronzhuk   2014-02-24  122  struct aemif_device {
5a7c81547c1db75 Ivan Khoronzhuk   2014-02-24  123  	void __iomem *base;
5a7c81547c1db75 Ivan Khoronzhuk   2014-02-24  124  	struct clk *clk;
5a7c81547c1db75 Ivan Khoronzhuk   2014-02-24  125  	unsigned long clk_rate;
5a7c81547c1db75 Ivan Khoronzhuk   2014-02-24  126  	u8 num_cs;
5a7c81547c1db75 Ivan Khoronzhuk   2014-02-24  127  	int cs_offset;
5a7c81547c1db75 Ivan Khoronzhuk   2014-02-24  128  	struct aemif_cs_data cs_data[NUM_CS];
0f034c3604121bf Bastien Curutchet 2024-10-30  129  	spinlock_t config_cs_lock;
5a7c81547c1db75 Ivan Khoronzhuk   2014-02-24 @130  };
5a7c81547c1db75 Ivan Khoronzhuk   2014-02-24  131  

-- 
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https://github.com/intel/lkp-tests/wiki