[PATCH v2 2/9] bus: mhi: Move sahara protocol driver under drivers/bus/mhi
From: Kishore Batta
Date: Sat Mar 07 2026 - 06:42:38 EST
The Sahara protocol driver is currently located under the QAIC
accelerator subsystem even though protocol itself is transported over the
MHI bus and is used by multiple Qualcomm flashless devices.
Relocate the Sahara protocol driver to drivers/bus/mhi and register it as
an independent MHI protocol driver. This avoids treating Sahara as QAIC
specific and makes it available for reuse by other MHI based devices.
As part of this move, introduce a dedicated Kconfig and Makefile under the
MHI subsystem and expose the sahara interface via a common header.
Signed-off-by: Kishore Batta <kishore.batta@xxxxxxxxxxxxxxxx>
---
drivers/accel/qaic/Kconfig | 1 +
drivers/accel/qaic/Makefile | 3 +--
drivers/accel/qaic/qaic_drv.c | 11 ++---------
drivers/bus/mhi/Kconfig | 1 +
drivers/bus/mhi/Makefile | 3 +++
drivers/bus/mhi/sahara/Kconfig | 18 ++++++++++++++++++
drivers/bus/mhi/sahara/Makefile | 2 ++
drivers/{accel/qaic => bus/mhi/sahara}/sahara.c | 16 +++++++++++-----
{drivers/accel/qaic => include/linux}/sahara.h | 0
9 files changed, 39 insertions(+), 16 deletions(-)
diff --git a/drivers/accel/qaic/Kconfig b/drivers/accel/qaic/Kconfig
index 116e42d152ca885b8c59e33c7a87519a0abc6bb3..1e5f1f4fa93c12d8ca8fb37633f2f0bee9997499 100644
--- a/drivers/accel/qaic/Kconfig
+++ b/drivers/accel/qaic/Kconfig
@@ -8,6 +8,7 @@ config DRM_ACCEL_QAIC
depends on DRM_ACCEL
depends on PCI && HAS_IOMEM
depends on MHI_BUS
+ select MHI_SAHARA
select CRC32
select WANT_DEV_COREDUMP
help
diff --git a/drivers/accel/qaic/Makefile b/drivers/accel/qaic/Makefile
index 71f727b74da3bb4478324689f02a7cea24a05c2d..e7b8458800072aa627f7f36c3257883aa56f4ce4 100644
--- a/drivers/accel/qaic/Makefile
+++ b/drivers/accel/qaic/Makefile
@@ -13,7 +13,6 @@ qaic-y := \
qaic_ras.o \
qaic_ssr.o \
qaic_sysfs.o \
- qaic_timesync.o \
- sahara.o
+ qaic_timesync.o
qaic-$(CONFIG_DEBUG_FS) += qaic_debugfs.o
diff --git a/drivers/accel/qaic/qaic_drv.c b/drivers/accel/qaic/qaic_drv.c
index 63fb8c7b4abcbe4f1b76c32106f4e8b9ea5e2c8e..76cc8086825e7949ed756d51fcb56a08f392d228 100644
--- a/drivers/accel/qaic/qaic_drv.c
+++ b/drivers/accel/qaic/qaic_drv.c
@@ -15,6 +15,7 @@
#include <linux/msi.h>
#include <linux/mutex.h>
#include <linux/pci.h>
+#include <linux/sahara.h>
#include <linux/spinlock.h>
#include <linux/workqueue.h>
#include <linux/wait.h>
@@ -32,7 +33,6 @@
#include "qaic_ras.h"
#include "qaic_ssr.h"
#include "qaic_timesync.h"
-#include "sahara.h"
MODULE_IMPORT_NS("DMA_BUF");
@@ -782,18 +782,12 @@ static int __init qaic_init(void)
ret = pci_register_driver(&qaic_pci_driver);
if (ret) {
pr_debug("qaic: pci_register_driver failed %d\n", ret);
- return ret;
+ goto free_pci;
}
ret = mhi_driver_register(&qaic_mhi_driver);
if (ret) {
pr_debug("qaic: mhi_driver_register failed %d\n", ret);
- goto free_pci;
- }
-
- ret = sahara_register();
- if (ret) {
- pr_debug("qaic: sahara_register failed %d\n", ret);
goto free_mhi;
}
@@ -847,7 +841,6 @@ static void __exit qaic_exit(void)
qaic_ras_unregister();
qaic_bootlog_unregister();
qaic_timesync_deinit();
- sahara_unregister();
mhi_driver_unregister(&qaic_mhi_driver);
pci_unregister_driver(&qaic_pci_driver);
}
diff --git a/drivers/bus/mhi/Kconfig b/drivers/bus/mhi/Kconfig
index b39a11e6c624ba00349cca22d74bd876020590ab..4acedb886adccc6f76f69c241d53106da59b491f 100644
--- a/drivers/bus/mhi/Kconfig
+++ b/drivers/bus/mhi/Kconfig
@@ -7,3 +7,4 @@
source "drivers/bus/mhi/host/Kconfig"
source "drivers/bus/mhi/ep/Kconfig"
+source "drivers/bus/mhi/sahara/Kconfig"
diff --git a/drivers/bus/mhi/Makefile b/drivers/bus/mhi/Makefile
index 354204b0ef3ae4030469a24a659f32429d592aef..e4af535e1bb1bc9481fae60d7eb347700d2e874c 100644
--- a/drivers/bus/mhi/Makefile
+++ b/drivers/bus/mhi/Makefile
@@ -3,3 +3,6 @@ obj-$(CONFIG_MHI_BUS) += host/
# Endpoint MHI stack
obj-$(CONFIG_MHI_BUS_EP) += ep/
+
+# Sahara MHI protocol
+obj-$(CONFIG_MHI_SAHARA) += sahara/
diff --git a/drivers/bus/mhi/sahara/Kconfig b/drivers/bus/mhi/sahara/Kconfig
new file mode 100644
index 0000000000000000000000000000000000000000..3f1caf6acd979a4af68aaf0e250aa54762e8cda5
--- /dev/null
+++ b/drivers/bus/mhi/sahara/Kconfig
@@ -0,0 +1,18 @@
+config MHI_SAHARA
+ tristate
+ depends on MHI_BUS
+ select FW_LOADER_COMPRESS
+ select FW_LOADER_COMPRESS_XZ
+ select FW_LOADER_COMPRESS_ZSTD
+ help
+ Enable support for the Sahara protocol transported over the MHI bus.
+
+ The Sahara protocol is used to transfer firmware images, retrieve
+ memory dumps and exchange command mode DDR calibration data between
+ host and device. This driver is not tied to a specific SoC and may be
+ used by multiple MHI based devices.
+
+ If unsure, say N.
+
+ To compile this driver as a module, choose M here: the module will be
+ called mhi_sahara.
diff --git a/drivers/bus/mhi/sahara/Makefile b/drivers/bus/mhi/sahara/Makefile
new file mode 100644
index 0000000000000000000000000000000000000000..fc02a25935011cbd7138ea8f24b88cf5b032a4ce
--- /dev/null
+++ b/drivers/bus/mhi/sahara/Makefile
@@ -0,0 +1,2 @@
+obj-$(CONFIG_MHI_SAHARA) += mhi_sahara.o
+mhi_sahara-y := sahara.o
diff --git a/drivers/accel/qaic/sahara.c b/drivers/bus/mhi/sahara/sahara.c
similarity index 99%
rename from drivers/accel/qaic/sahara.c
rename to drivers/bus/mhi/sahara/sahara.c
index fd3c3b2d1fd3bb698809e6ca669128e2dce06613..8ff7b6425ac5423ef8f32117151dca10397686a8 100644
--- a/drivers/accel/qaic/sahara.c
+++ b/drivers/bus/mhi/sahara/sahara.c
@@ -1,6 +1,8 @@
-// SPDX-License-Identifier: GPL-2.0-only
-
-/* Copyright (c) 2024 Qualcomm Innovation Center, Inc. All rights reserved. */
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2018-2020, The Linux Foundation. All rights reserved.
+ *
+ */
#include <linux/devcoredump.h>
#include <linux/firmware.h>
@@ -9,12 +11,11 @@
#include <linux/minmax.h>
#include <linux/mod_devicetable.h>
#include <linux/overflow.h>
+#include <linux/sahara.h>
#include <linux/types.h>
#include <linux/vmalloc.h>
#include <linux/workqueue.h>
-#include "sahara.h"
-
#define SAHARA_HELLO_CMD 0x1 /* Min protocol version 1.0 */
#define SAHARA_HELLO_RESP_CMD 0x2 /* Min protocol version 1.0 */
#define SAHARA_READ_DATA_CMD 0x3 /* Min protocol version 1.0 */
@@ -928,8 +929,13 @@ int sahara_register(void)
{
return mhi_driver_register(&sahara_mhi_driver);
}
+module_init(sahara_register);
void sahara_unregister(void)
{
mhi_driver_unregister(&sahara_mhi_driver);
}
+module_exit(sahara_unregister);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Qualcomm Sahara MHI protocol driver");
diff --git a/drivers/accel/qaic/sahara.h b/include/linux/sahara.h
similarity index 100%
rename from drivers/accel/qaic/sahara.h
rename to include/linux/sahara.h
--
2.34.1