[PATCH v4 1/6] remoteproc: qcom: fix sparse warnings for __iomem annotated mem_region

[Mukesh Ojha <mukesh.ojha@oss.qualcomm.com>]

The firmware memory regions in qcom_adsp, qcom_pas and qcom_wcnss are
mapped using devm_ioremap_wc() / devm_ioremap_resource_wc(), which
return void __iomem *. However, the mem_region (and dtb_mem_region)
fields in the respective driver structs were declared as plain void *,
causing sparse to flag address space mismatches:

qcom_q6v5_adsp.c:639:26: warning: incorrect type in assignment (different address spaces)
qcom_q6v5_adsp.c:639:26:    expected void *mem_region
qcom_q6v5_adsp.c:639:26:    got void [noderef] __iomem *
qcom_q6v5_pas.c:141:45: warning: incorrect type in argument 2 (different address spaces)
qcom_q6v5_pas.c:141:45:    expected void const volatile [noderef] __iomem *src
qcom_q6v5_pas.c:141:45:    got void *
qcom_q6v5_pas.c:637:25: warning: incorrect type in assignment (different address spaces)
qcom_q6v5_pas.c:637:25:    expected void *mem_region
qcom_q6v5_pas.c:637:25:    got void [noderef] __iomem *
qcom_q6v5_pas.c:654:29: warning: incorrect type in assignment (different address spaces)
qcom_q6v5_pas.c:654:29:    expected void *dtb_mem_region
qcom_q6v5_pas.c:654:29:    got void [noderef] __iomem *
qcom_wcnss.c:540:27: warning: incorrect type in assignment (different address spaces)
qcom_wcnss.c:540:27:    expected void *mem_region
qcom_wcnss.c:540:27:    got void [noderef] __iomem *

Fix this by annotating the struct fields with __iomem to correctly
reflect the address space of the underlying mapping.

These regions are subsequently passed to qcom_mdt_load(),
qcom_mdt_load_no_init() and qcom_mdt_pas_load(), all of which take
void * and use plain memcpy()/memset() internally to write firmware
segments into the region. This is intentional and safe: the mappings
are write-combining (WC), which on arm64 permits bulk CPU stores
without requiring the memcpy_toio()/memset_io() accessors. Changing
the MDT loader API to accept void __iomem * would be a more invasive
change and would affect callers.

Signed-off-by: Mukesh Ojha <mukesh.ojha@oss.qualcomm.com>
---
 drivers/remoteproc/qcom_q6v5_adsp.c |  6 +++---
 drivers/remoteproc/qcom_q6v5_pas.c  | 10 +++++-----
 drivers/remoteproc/qcom_wcnss.c     |  6 +++---
 3 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/drivers/remoteproc/qcom_q6v5_adsp.c b/drivers/remoteproc/qcom_q6v5_adsp.c
index b5c8d6d38c9c..d2b50af6d748 100644
--- a/drivers/remoteproc/qcom_q6v5_adsp.c
+++ b/drivers/remoteproc/qcom_q6v5_adsp.c
@@ -105,7 +105,7 @@ struct qcom_adsp {
 
 	phys_addr_t mem_phys;
 	phys_addr_t mem_reloc;
-	void *mem_region;
+	void __iomem *mem_region;
 	size_t mem_size;
 	bool has_iommu;
 
@@ -318,7 +318,7 @@ static int adsp_load(struct rproc *rproc, const struct firmware *fw)
 	int ret;
 
 	ret = qcom_mdt_load_no_init(adsp->dev, fw, rproc->firmware,
-				    adsp->mem_region, adsp->mem_phys,
+				    (__force void *)adsp->mem_region, adsp->mem_phys,
 				    adsp->mem_size, &adsp->mem_reloc);
 	if (ret)
 		return ret;
@@ -491,7 +491,7 @@ static void *adsp_da_to_va(struct rproc *rproc, u64 da, size_t len, bool *is_iom
 	if (offset < 0 || offset + len > adsp->mem_size)
 		return NULL;
 
-	return adsp->mem_region + offset;
+	return (__force void *)adsp->mem_region + offset;
 }
 
 static int adsp_parse_firmware(struct rproc *rproc, const struct firmware *fw)
diff --git a/drivers/remoteproc/qcom_q6v5_pas.c b/drivers/remoteproc/qcom_q6v5_pas.c
index da27d1d3c9da..45be8c5049e1 100644
--- a/drivers/remoteproc/qcom_q6v5_pas.c
+++ b/drivers/remoteproc/qcom_q6v5_pas.c
@@ -100,8 +100,8 @@ struct qcom_pas {
 	phys_addr_t mem_reloc;
 	phys_addr_t dtb_mem_reloc;
 	phys_addr_t region_assign_phys[MAX_ASSIGN_COUNT];
-	void *mem_region;
-	void *dtb_mem_region;
+	void __iomem *mem_region;
+	void __iomem *dtb_mem_region;
 	size_t mem_size;
 	size_t dtb_mem_size;
 	size_t region_assign_size[MAX_ASSIGN_COUNT];
@@ -241,7 +241,7 @@ static int qcom_pas_load(struct rproc *rproc, const struct firmware *fw)
 		}
 
 		ret = qcom_mdt_pas_load(pas->dtb_pas_ctx, pas->dtb_firmware,
-					pas->dtb_firmware_name, pas->dtb_mem_region,
+					pas->dtb_firmware_name, (__force void *)pas->dtb_mem_region,
 					&pas->dtb_mem_reloc);
 		if (ret)
 			goto release_dtb_metadata;
@@ -319,7 +319,7 @@ static int qcom_pas_start(struct rproc *rproc)
 	}
 
 	ret = qcom_mdt_pas_load(pas->pas_ctx, pas->firmware, rproc->firmware,
-				pas->mem_region, &pas->mem_reloc);
+				(__force void *)pas->mem_region, &pas->mem_reloc);
 	if (ret)
 		goto release_pas_metadata;
 
@@ -445,7 +445,7 @@ static void *qcom_pas_da_to_va(struct rproc *rproc, u64 da, size_t len, bool *is
 	if (is_iomem)
 		*is_iomem = true;
 
-	return pas->mem_region + offset;
+	return (__force void *)pas->mem_region + offset;
 }
 
 static int qcom_pas_parse_firmware(struct rproc *rproc, const struct firmware *fw)
diff --git a/drivers/remoteproc/qcom_wcnss.c b/drivers/remoteproc/qcom_wcnss.c
index 4add9037dbd5..da68bc1903be 100644
--- a/drivers/remoteproc/qcom_wcnss.c
+++ b/drivers/remoteproc/qcom_wcnss.c
@@ -94,7 +94,7 @@ struct qcom_wcnss {
 
 	phys_addr_t mem_phys;
 	phys_addr_t mem_reloc;
-	void *mem_region;
+	void __iomem *mem_region;
 	size_t mem_size;
 
 	struct qcom_rproc_subdev smd_subdev;
@@ -158,7 +158,7 @@ static int wcnss_load(struct rproc *rproc, const struct firmware *fw)
 	int ret;
 
 	ret = qcom_mdt_load(wcnss->dev, fw, rproc->firmware, WCNSS_PAS_ID,
-			    wcnss->mem_region, wcnss->mem_phys,
+			    (__force void *)wcnss->mem_region, wcnss->mem_phys,
 			    wcnss->mem_size, &wcnss->mem_reloc);
 	if (ret)
 		return ret;
@@ -327,7 +327,7 @@ static void *wcnss_da_to_va(struct rproc *rproc, u64 da, size_t len, bool *is_io
 	if (offset < 0 || offset + len > wcnss->mem_size)
 		return NULL;
 
-	return wcnss->mem_region + offset;
+	return (__force void *)wcnss->mem_region + offset;
 }
 
 static const struct rproc_ops wcnss_ops = {
-- 
2.53.0