From: Georgi Djakov <georgi.djakov@oss.qualcomm.com>
To: andersson@kernel.org, konradybcio@kernel.org,
abelvesa@kernel.org, robh@kernel.org, krzk+dt@kernel.org,
conor+dt@kernel.org, minchan@kernel.org,
senozhatsky@chromium.org
Cc: axboe@kernel.dk, rostedt@goodmis.org, mhiramat@kernel.org,
mathieu.desnoyers@efficios.com, linux-arm-msm@vger.kernel.org,
devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-block@vger.kernel.org, linux-trace-kernel@vger.kernel.org,
djakov@kernel.org
Subject: [PATCH 4/6] zram: Add QPaCE zcomp backend
Date: Wed, 30 Sep 2026 07:52:13 -0700 [thread overview]
Message-ID: <20260930145215.3380977-5-georgi.djakov@oss.qualcomm.com> (raw)
In-Reply-To: <20260930145215.3380977-1-georgi.djakov@oss.qualcomm.com>
Add a zcomp backend for the Qualcomm Page Compression Engine (QPaCE) so
zram can expose qpace-lz4 as a selectable compression algorithm when the
QPaCE driver is available.
Compress and decompress operations are handled via the QPaCE urgent
synchronous path: each request DMA-maps the source and destination
buffers, issues a blocking hardware command, and returns the result size.
Signed-off-by: Georgi Djakov <georgi.djakov@oss.qualcomm.com>
---
drivers/block/zram/Kconfig | 11 +++
drivers/block/zram/Makefile | 1 +
drivers/block/zram/backend_qpace.c | 134 +++++++++++++++++++++++++++++
drivers/block/zram/backend_qpace.h | 13 +++
drivers/block/zram/zcomp.c | 11 ++-
5 files changed, 168 insertions(+), 2 deletions(-)
create mode 100644 drivers/block/zram/backend_qpace.c
create mode 100644 drivers/block/zram/backend_qpace.h
diff --git a/drivers/block/zram/Kconfig b/drivers/block/zram/Kconfig
index 402b7b175863..eece67e7ea83 100644
--- a/drivers/block/zram/Kconfig
+++ b/drivers/block/zram/Kconfig
@@ -44,6 +44,17 @@ config ZRAM_BACKEND_842
select 842_COMPRESS
select 842_DECOMPRESS
+config ZRAM_BACKEND_QPACE
+ bool "QPaCE compression support"
+ depends on ZRAM
+ depends on QCOM_PAGE_COMPRESSION_ENGINE = y || \
+ (ZRAM = m && QCOM_PAGE_COMPRESSION_ENGINE = m)
+ help
+ Enable Qualcomm Page Compression Engine (QPaCE) hardware
+ acceleration as a zram backend. When selected, zram offloads
+ synchronous compress and decompress operations to the QPaCE
+ urgent command path, reducing CPU overhead.
+
config ZRAM_BACKEND_FORCE_LZO
depends on ZRAM
def_bool !ZRAM_BACKEND_LZ4 && !ZRAM_BACKEND_LZ4HC && \
diff --git a/drivers/block/zram/Makefile b/drivers/block/zram/Makefile
index 0fdefd576691..9e1c35f942e0 100644
--- a/drivers/block/zram/Makefile
+++ b/drivers/block/zram/Makefile
@@ -8,5 +8,6 @@ zram-$(CONFIG_ZRAM_BACKEND_LZ4HC) += backend_lz4hc.o
zram-$(CONFIG_ZRAM_BACKEND_ZSTD) += backend_zstd.o
zram-$(CONFIG_ZRAM_BACKEND_DEFLATE) += backend_deflate.o
zram-$(CONFIG_ZRAM_BACKEND_842) += backend_842.o
+zram-$(CONFIG_ZRAM_BACKEND_QPACE) += backend_qpace.o
obj-$(CONFIG_ZRAM) += zram.o
diff --git a/drivers/block/zram/backend_qpace.c b/drivers/block/zram/backend_qpace.c
new file mode 100644
index 000000000000..3af13727adef
--- /dev/null
+++ b/drivers/block/zram/backend_qpace.c
@@ -0,0 +1,134 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
+ */
+
+#include <linux/dma-mapping.h>
+#include <linux/slab.h>
+#include <linux/soc/qcom/qpace.h>
+
+#include "backend_qpace.h"
+
+struct qpace_ctx {
+ struct device *dev;
+ void *in_buf;
+ dma_addr_t in_dma;
+ void *out_buf;
+ dma_addr_t out_dma;
+};
+
+static int qpace_setup_lz4_params(struct zcomp_params *params)
+{
+ params->drv_data = (void *)&qpace_lz4_algorithm;
+ return 0;
+}
+
+static void qpace_release_params(struct zcomp_params *params)
+{
+}
+
+static int qpace_create_ctx(struct zcomp_params *params, struct zcomp_ctx *ctx)
+{
+ struct device *dev = qpace_get_dma_dev();
+ struct qpace_ctx *cc;
+
+ if (!dev)
+ return -ENODEV;
+
+ cc = kzalloc_obj(*cc, GFP_KERNEL);
+ if (!cc)
+ return -ENOMEM;
+
+ cc->dev = dev;
+ cc->in_buf = dma_alloc_coherent(dev, PAGE_SIZE, &cc->in_dma, GFP_KERNEL);
+ if (!cc->in_buf)
+ goto err_free;
+
+ cc->out_buf = dma_alloc_coherent(dev, PAGE_SIZE, &cc->out_dma, GFP_KERNEL);
+ if (!cc->out_buf)
+ goto err_free_in;
+
+ ctx->context = cc;
+ return 0;
+
+err_free_in:
+ dma_free_coherent(dev, PAGE_SIZE, cc->in_buf, cc->in_dma);
+err_free:
+ kfree(cc);
+ return -ENOMEM;
+}
+
+static void qpace_destroy_ctx(struct zcomp_ctx *ctx)
+{
+ struct qpace_ctx *cc = ctx->context;
+
+ if (!cc)
+ return;
+
+ dma_free_coherent(cc->dev, PAGE_SIZE, cc->out_buf, cc->out_dma);
+ dma_free_coherent(cc->dev, PAGE_SIZE, cc->in_buf, cc->in_dma);
+ kfree(cc);
+ ctx->context = NULL;
+}
+
+static int qpace_compress(struct zcomp_params *params, struct zcomp_ctx *ctx,
+ struct zcomp_req *req)
+{
+ struct qpace_algorithm *algo = params->drv_data;
+ struct qpace_ctx *cc = ctx->context;
+ int ret;
+
+ memcpy(cc->in_buf, req->src, req->src_len);
+
+ ret = qpace_urgent_compress(cc->in_dma, cc->out_dma, algo);
+
+ if (ret == -E2BIG || ret >= PAGE_SIZE) {
+ req->dst_len = PAGE_SIZE;
+ return 0;
+ }
+ if (ret <= 0)
+ return ret < 0 ? ret : -EIO;
+
+ if (ret > req->dst_len)
+ return -EIO;
+
+ memcpy(req->dst, cc->out_buf, ret);
+ req->dst_len = ret;
+
+ return 0;
+}
+
+static int qpace_decompress(struct zcomp_params *params, struct zcomp_ctx *ctx,
+ struct zcomp_req *req)
+{
+ struct qpace_algorithm *algo = params->drv_data;
+ struct qpace_ctx *cc = ctx->context;
+ int ret;
+
+ if (req->src_len > PAGE_SIZE)
+ return -EINVAL;
+
+ memcpy(cc->in_buf, req->src, req->src_len);
+
+ ret = qpace_urgent_decompress(cc->in_dma, cc->out_dma, req->src_len, algo);
+ if (ret <= 0)
+ return ret < 0 ? ret : -EIO;
+
+ if (ret > req->dst_len)
+ return -EIO;
+
+ memcpy(req->dst, cc->out_buf, ret);
+ req->dst_len = ret;
+
+ return 0;
+}
+
+const struct zcomp_ops backend_qpace_lz4 = {
+ .name = "qpace-lz4",
+ .setup_params = qpace_setup_lz4_params,
+ .release_params = qpace_release_params,
+ .create_ctx = qpace_create_ctx,
+ .destroy_ctx = qpace_destroy_ctx,
+ .compress = qpace_compress,
+ .decompress = qpace_decompress,
+};
diff --git a/drivers/block/zram/backend_qpace.h b/drivers/block/zram/backend_qpace.h
new file mode 100644
index 000000000000..03747405edcf
--- /dev/null
+++ b/drivers/block/zram/backend_qpace.h
@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
+ */
+
+#ifndef __BACKEND_QPACE_H__
+#define __BACKEND_QPACE_H__
+
+#include "zcomp.h"
+
+extern const struct zcomp_ops backend_qpace_lz4;
+
+#endif /* __BACKEND_QPACE_H__ */
diff --git a/drivers/block/zram/zcomp.c b/drivers/block/zram/zcomp.c
index 028e2f0f587e..b5bd0b11a975 100644
--- a/drivers/block/zram/zcomp.c
+++ b/drivers/block/zram/zcomp.c
@@ -22,6 +22,10 @@
#include "backend_deflate.h"
#include "backend_842.h"
+#if IS_ENABLED(CONFIG_ZRAM_BACKEND_QPACE)
+#include "backend_qpace.h"
+#endif
+
static const struct zcomp_ops *backends[] = {
#if IS_ENABLED(CONFIG_ZRAM_BACKEND_LZO)
&backend_lzorle,
@@ -41,6 +45,9 @@ static const struct zcomp_ops *backends[] = {
#endif
#if IS_ENABLED(CONFIG_ZRAM_BACKEND_842)
&backend_842,
+#endif
+#if IS_ENABLED(CONFIG_ZRAM_BACKEND_QPACE)
+ &backend_qpace_lz4,
#endif
NULL
};
@@ -80,10 +87,10 @@ static const struct zcomp_ops *lookup_backend_ops(const char *comp)
while (backends[i]) {
if (sysfs_streq(comp, backends[i]->name))
- break;
+ return backends[i];
i++;
}
- return backends[i];
+ return NULL;
}
const char *zcomp_lookup_backend_name(const char *comp)
next prev parent reply other threads:[~2026-09-30 14:52 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-30 14:52 [PATCH 0/6] soc: qcom: Add Qualcomm Page Compression Engine (QPaCE) driver Georgi Djakov
2026-09-30 14:52 ` [PATCH 1/6] dt-bindings: soc: qcom: Add QPaCE binding Georgi Djakov
2026-10-02 6:10 ` Krzysztof Kozlowski
2026-09-30 14:52 ` [PATCH 2/6] soc: qcom: qpace: Add Qualcomm Page Compression Engine driver Georgi Djakov
2026-10-01 8:50 ` Krzysztof Kozlowski
2026-10-06 23:51 ` Oreoluwa Babatunde
2026-10-07 7:51 ` Krzysztof Kozlowski
2026-10-08 0:08 ` Oreoluwa Babatunde
2026-09-30 14:52 ` [PATCH 3/6] trace: qpace: Add tracepoints for QPaCE operations Georgi Djakov
2026-09-30 14:52 ` Georgi Djakov [this message]
2026-10-01 5:43 ` [PATCH 4/6] zram: Add QPaCE zcomp backend Sergey Senozhatsky
2026-10-06 23:53 ` Oreoluwa Babatunde
2026-10-08 3:52 ` Sergey Senozhatsky
2026-10-01 8:51 ` Krzysztof Kozlowski
2026-10-01 10:27 ` Sergey Senozhatsky
2026-10-07 0:04 ` Oreoluwa Babatunde
2026-10-07 0:03 ` Oreoluwa Babatunde
2026-09-30 14:52 ` [PATCH 5/6] soc: qcom: qpace: Add LLCC slice support Georgi Djakov
2026-09-30 14:52 ` [PATCH 6/6] arm64: dts: qcom: hawi: Add QPaCE DT node Georgi Djakov
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