serial: Use conftest to find if uart_ops has set_termios has const arg

Use conftest to determine if set_termios of struct uart_ops
has const type argument or not. The argument type is changed
from commit bec5b814d46c ("serial: Make ->set_termios() old
ktermios const") in Linux 6.1

Bug 4387902

Change-Id: I175aac51ac2c2b99b9eedc69260ccb6b0c38571e
Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/c/linux-nv-oot/+/3037040
Reviewed-by: Bitan Biswas <bbiswas@nvidia.com>
GVS: Gerrit_Virtual_Submit <buildbot_gerritrpt@nvidia.com>

drivers/tty/serial/wch_35x/wch_serial.c

@@ -12,8 +12,6 @@
 
 #include <nvidia/conftest.h>
 
-#include <linux/version.h>
-
 #include "wch_common.h"
 
 #if defined(NV_DEFINE_SEMAPHORE_HAS_NUMBER_ARG)
@@ -82,7 +80,7 @@ static int ser_get_count(struct ser_state *, struct serial_icounter_struct *);
 static int ser_ioctl(struct tty_struct *, unsigned int, unsigned long);
 static void ser_hangup(struct tty_struct *);
 unsigned int ser_get_divisor(struct ser_port *, unsigned int, bool);
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 1, 0)
+#if defined(NV_TTY_OPERATIONS_STRUCT_SET_TERMIOS_HAS_CONST_KTERMIOS_ARG) /* Linux 6.1 */
 unsigned int ser_get_baud_rate(struct ser_port *, struct WCHTERMIOS *, const struct WCHTERMIOS *, unsigned int, unsigned int);
 static void ser_change_speed(struct ser_state *state, const struct WCHTERMIOS *old_termios);
 #else
@@ -108,7 +106,7 @@ static void wch_ser_break_ctl(struct ser_port *, int);
 static int wch_ser_startup(struct ser_port *);
 static void wch_ser_shutdown(struct ser_port *);
 static unsigned int wch_ser_get_divisor(struct ser_port *, unsigned int, bool);
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 1, 0)
+#if defined(NV_TTY_OPERATIONS_STRUCT_SET_TERMIOS_HAS_CONST_KTERMIOS_ARG) /* Linux 6.1 */
 static void wch_ser_set_termios(struct ser_port *port, struct WCHTERMIOS *termios, const struct WCHTERMIOS *old);
 #else
 static void wch_ser_set_termios(struct ser_port *port, struct WCHTERMIOS *termios, struct WCHTERMIOS *old);
@@ -1285,7 +1283,7 @@ unsigned int ser_get_divisor(struct ser_port *port, unsigned int baud, bool btwi
     return quot;
 }
 
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 1, 0)
+#if defined(NV_TTY_OPERATIONS_STRUCT_SET_TERMIOS_HAS_CONST_KTERMIOS_ARG) /* Linux 6.1 */
 unsigned int ser_get_baud_rate(struct ser_port *port, struct WCHTERMIOS *termios,
 			       const struct WCHTERMIOS *old, unsigned int min, unsigned int max)
 #else
@@ -1356,7 +1354,7 @@ unsigned int ser_get_baud_rate(struct ser_port *port, struct WCHTERMIOS *termios
     return 0;
 }
 
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 1, 0)
+#if defined(NV_TTY_OPERATIONS_STRUCT_SET_TERMIOS_HAS_CONST_KTERMIOS_ARG) /* Linux 6.1 */
 static void ser_change_speed(struct ser_state *state, const struct WCHTERMIOS *old_termios)
 #else
 static void ser_change_speed(struct ser_state *state, struct WCHTERMIOS *old_termios)
@@ -1384,7 +1382,7 @@ static void ser_change_speed(struct ser_state *state, struct WCHTERMIOS *old_ter
     wch_ser_set_termios(port, &termios, old_termios);
 }
 
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 1, 0)
+#if defined(NV_TTY_OPERATIONS_STRUCT_SET_TERMIOS_HAS_CONST_KTERMIOS_ARG) /* Linux 6.1 */
 static void ser_set_termios(struct tty_struct *tty, const struct WCHTERMIOS *old_termios)
 #else
 static void ser_set_termios(struct tty_struct *tty, struct WCHTERMIOS *old_termios)
@@ -1965,7 +1963,7 @@ static unsigned int wch_ser_get_divisor(struct ser_port *port, unsigned int baud
     return quot;
 }
 
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 1, 0)
+#if defined(NV_TTY_OPERATIONS_STRUCT_SET_TERMIOS_HAS_CONST_KTERMIOS_ARG) /* Linux 6.1 */
 static void wch_ser_set_termios(struct ser_port *port, struct WCHTERMIOS *termios, const struct WCHTERMIOS *old)
 #else
 static void wch_ser_set_termios(struct ser_port *port, struct WCHTERMIOS *termios, struct WCHTERMIOS *old)

scripts/conftest/Makefile

@@ -153,6 +153,7 @@ NV_CONFTEST_FUNCTION_COMPILE_TESTS += tc_taprio_qopt_offload_struct_has_cmd
 NV_CONFTEST_FUNCTION_COMPILE_TESTS += tegra_dev_iommu_get_stream_id
 NV_CONFTEST_FUNCTION_COMPILE_TESTS += tegra_ivc_struct_has_iosys_map
 NV_CONFTEST_FUNCTION_COMPILE_TESTS += tty_operations_struct_write_has_u8_ptr_arg
+NV_CONFTEST_FUNCTION_COMPILE_TESTS += tty_operations_struct_set_termios_has_const_ktermios_arg
 NV_CONFTEST_FUNCTION_COMPILE_TESTS += ufs_hba_variant_ops_suspend_has_status_arg
 NV_CONFTEST_FUNCTION_COMPILE_TESTS += v4l2_async_connection_struct_present
 NV_CONFTEST_FUNCTION_COMPILE_TESTS += v4l2_async_match_type_enum_present

scripts/conftest/conftest.sh

@@ -7521,6 +7521,25 @@ compile_test() {
             compile_check_conftest "$CODE" "NV_TTY_OPERATIONS_STRUCT_WRITE_HAS_U8_PTR_ARG" "" "functions"
         ;;
 
+        tty_operations_struct_set_termios_has_const_ktermios_arg)
+            #
+            # Determine if the function set_termios of tty_operations struct has the const type argument or not.
+            #
+            # The callback function of tty_operations has the const type argument from the commit bec5b814d46c
+            # ("serial: Make ->set_termios() old ktermios const") in Linux 6.1.
+            #
+            CODE="
+            #include <linux/tty.h>
+            #include <linux/tty_driver.h>
+            static inline void test_set_termios(struct tty_struct *tty, const struct ktermios *old) {
+            }
+            static struct tty_operations tty_ops = {
+                  .set_termios = test_set_termios,
+            };"
+
+            compile_check_conftest "$CODE" "NV_TTY_OPERATIONS_STRUCT_SET_TERMIOS_HAS_CONST_KTERMIOS_ARG" "" "types"
+        ;;
+
         ufs_hba_variant_ops_suspend_has_status_arg)
             #
             # Determine if the 'suspend' function for the