audioreach-driver: fix gpr callback break after const ABI update

audioreach-driver/ar_kcompat.h

@@ -0,0 +1,70 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+// Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
+#ifndef __AR_KCOMPAT_H__
+#define __AR_KCOMPAT_H__
+
+#include <linux/version.h>
+#include <linux/types.h>
+
+/*
+ * Detect whether the kernel expects GPR callback with:
+ *   - <= 6.19 : struct gpr_resp_pkt * (non-const)
+ *   - >= 7.0 : const struct gpr_resp_pkt * (const)
+ *
+ * Allow a build-time override (vendors may backport).
+ *
+ * Use:
+ *   -D HAVE_GPR_CB_CONST   -> force >=7.0 behavior (const)
+ *   -D HAVE_GPR_CB_MUTABLE -> force <=6.19 behavior (non-const)
+ *
+ * If neither is defined, pick based on LINUX_VERSION_CODE.
+ */
+#if defined(HAVE_GPR_CB_CONST) && defined(HAVE_GPR_CB_MUTABLE)
+# error "Define at most one of HAVE_GPR_CB_CONST or HAVE_GPR_CB_MUTABLE"
+#endif
+
+#if defined(HAVE_GPR_CB_CONST)
+# define AR_HAVE_GPR_CB_CONST 1
+#elif defined(HAVE_GPR_CB_MUTABLE)
+# define AR_HAVE_GPR_CB_CONST 0
+#elif LINUX_VERSION_CODE >= KERNEL_VERSION(7, 0, 0)
+# define AR_HAVE_GPR_CB_CONST 1
+#else
+# define AR_HAVE_GPR_CB_CONST 0
+#endif
+
+/*
+ * Thunk generator for GPR callbacks.
+ *
+ * The driver provides a version‑independent core:
+ *     int name_core(const struct gpr_resp_pkt *data, void *priv, int op);
+ *
+ * This macro emits an ABI‑appropriate wrapper ('name') and forwards the
+ * packet to the const‑correct core. Legacy kernels that pass a mutable
+ * gpr_resp_pkt pointer are handled by accepting the mutable form and
+ * forwarding it as const. The packet is not modified.
+ *
+ * For kernels that require in‑place packet modification, a local copy must
+ * be created before invoking the core. Current code paths do not modify
+ * the packet.
+ */
+
+#define AR_GPR_CB_WRAPPER(name)                                             \
+	static int name##_core(const struct gpr_resp_pkt *data,                  \
+					void *priv, int op);                              \
+	__AR_GPR_CB_DECL(name)                                                  \
+	{                                                                       \
+		/* Non‑const legacy pointer; handled as read‑only. */               \
+		return name##_core((const struct gpr_resp_pkt *)data, priv, op);    \
+	}
+
+/* Emit the kernel-facing callback prototype */
+#if AR_HAVE_GPR_CB_CONST
+# define __AR_GPR_CB_DECL(name) \
+	static int name(const struct gpr_resp_pkt *data, void *priv, int op)
+#else
+# define __AR_GPR_CB_DECL(name) \
+	static int name(struct gpr_resp_pkt *data, void *priv, int op)
+#endif
+
+#endif /* __AR_KCOMPAT_H__ */

audioreach-driver/q6apm_audio_pkt.c

@@ -29,6 +29,7 @@
 #include "audioreach.h"
 #include "q6apm.h"
 #include "q6prm_audioreach.h"
+#include "ar_kcompat.h"
 
 #define APM_CMD_SHARED_MEM_MAP_REGIONS          0x0100100C
 #define APM_MEMORY_MAP_BIT_MASK_IS_OFFSET_MODE  0x00000004UL
@@ -590,7 +591,14 @@ static int q6apm_audio_pkt_probe(gpr_device_t *adev)
 	return ret;
 }
 
-static int q6apm_audio_pkt_callback(const struct gpr_resp_pkt *data, void *priv, int op)
+/*
+ * Generate the kernel-facing wrapper with the correct signature
+ * for <=6.19 (non-const) and >=7.0 (const). The wrapper calls
+ * q6apm_audio_pkt_callback_core() which always uses 'const'.
+ */
+AR_GPR_CB_WRAPPER(q6apm_audio_pkt_callback)
+
+static int q6apm_audio_pkt_callback_core(const struct gpr_resp_pkt *data, void *priv, int op)
 {
 	gpr_device_t *gdev = priv;
 	struct q6apm_audio_pkt *apm = dev_get_drvdata(&gdev->dev);
@@ -638,8 +646,8 @@ static int q6apm_audio_pkt_callback(const struct gpr_resp_pkt *data, void *priv,
 
         skb = alloc_skb(pkt_size, GFP_ATOMIC);
 		if (!skb) {
-				kfree(pkt);
-                return -ENOMEM;
+			kfree(pkt);
+			return -ENOMEM;
 		}
 
         skb_put_data(skb, (void *)pkt, pkt_size);

audioreach-driver/q6prm_audioreach.c

@@ -17,6 +17,7 @@
 #include "q6prm.h"
 #include "audioreach.h"
 #include "q6prm_audioreach.h"
+#include "ar_kcompat.h"
 
 struct q6prm {
 	struct device *dev;
@@ -277,7 +278,15 @@ int q6prm_audioreach_set_lpass_clock(struct device *dev, int clk_id, int clk_att
 	return q6prm_audioreach_release_lpass_clock(dev, clk_id, clk_attr, clk_root, freq);
 }
 
-static int prm_audioreach_callback(const struct gpr_resp_pkt *data, void *priv, int op)
+/*
+ * Generate the kernel-facing wrapper with the correct signature
+ * for <=6.19 (non-const) and >=7.0 (const). The wrapper calls
+ * prm_audioreach_callback_core() which always uses 'const'.
+ */
+AR_GPR_CB_WRAPPER(prm_audioreach_callback)
+
+static int prm_audioreach_callback_core(const struct gpr_resp_pkt *data,
+					void *priv, int op)
 {
 	gpr_device_t *gdev = priv;
 	struct q6prm *prm = dev_get_drvdata(&gdev->dev);