Re: [PATCH v2 3/4] soc: qcom: smem: Support reserved-memory description

From: Vladimir Zapolskiy
Date: Fri Oct 01 2021 - 03:08:45 EST


Hi Bjorn,

On 9/30/21 9:21 PM, Bjorn Andersson wrote:
Practically all modern Qualcomm platforms has a single reserved-memory
region for SMEM. So rather than having to describe SMEM in the form of a
node with a reference to a reserved-memory node, allow the SMEM device
to be instantiated directly from the reserved-memory node.

The current means of falling back to dereferencing the "memory-region"
is kept as a fallback, if it's determined that the SMEM node is a
reserved-memory node.

The "qcom,smem" compatible is added to the reserved_mem_matches list, to
allow the reserved-memory device to be probed.

In order to retain the readability of the code, the resolution of
resources is split from the actual ioremapping.

Signed-off-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
---

Changes since v1:
- None

drivers/of/platform.c | 1 +
drivers/soc/qcom/smem.c | 57 ++++++++++++++++++++++++++++-------------
2 files changed, 40 insertions(+), 18 deletions(-)

diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index 32d5ff8df747..07813fb1ef37 100644
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c
@@ -505,6 +505,7 @@ EXPORT_SYMBOL_GPL(of_platform_default_populate);
static const struct of_device_id reserved_mem_matches[] = {
{ .compatible = "qcom,rmtfs-mem" },
{ .compatible = "qcom,cmd-db" },
+ { .compatible = "qcom,smem" },
{ .compatible = "ramoops" },
{ .compatible = "nvmem-rmem" },
{}
diff --git a/drivers/soc/qcom/smem.c b/drivers/soc/qcom/smem.c
index 4fb5aeeb0843..c7e519bfdc8a 100644
--- a/drivers/soc/qcom/smem.c
+++ b/drivers/soc/qcom/smem.c
@@ -9,6 +9,7 @@
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_address.h>
+#include <linux/of_reserved_mem.h>
#include <linux/platform_device.h>
#include <linux/sizes.h>
#include <linux/slab.h>
@@ -240,7 +241,7 @@ static const u8 SMEM_INFO_MAGIC[] = { 0x53, 0x49, 0x49, 0x49 }; /* SIII */
* @size: size of the memory region
*/
struct smem_region {
- u32 aux_base;
+ phys_addr_t aux_base;
void __iomem *virt_base;
size_t size;
};
@@ -499,7 +500,7 @@ static void *qcom_smem_get_global(struct qcom_smem *smem,
for (i = 0; i < smem->num_regions; i++) {
region = &smem->regions[i];
- if (region->aux_base == aux_base || !aux_base) {
+ if ((u32)region->aux_base == aux_base || !aux_base) {
if (size != NULL)
*size = le32_to_cpu(entry->size);
return region->virt_base + le32_to_cpu(entry->offset);
@@ -664,7 +665,7 @@ phys_addr_t qcom_smem_virt_to_phys(void *p)
if (p < region->virt_base + region->size) {
u64 offset = p - region->virt_base;
- return (phys_addr_t)region->aux_base + offset;
+ return region->aux_base + offset;
}
}
@@ -863,12 +864,12 @@ qcom_smem_enumerate_partitions(struct qcom_smem *smem, u16 local_host)
return 0;
}
-static int qcom_smem_map_memory(struct qcom_smem *smem, struct device *dev,
- const char *name, int i)
+static int qcom_smem_resolve_mem(struct qcom_smem *smem, const char *name,
+ struct smem_region *region)
{
+ struct device *dev = smem->dev;
struct device_node *np;
struct resource r;
- resource_size_t size;
int ret;
np = of_parse_phandle(dev->of_node, name, 0);
@@ -881,13 +882,9 @@ static int qcom_smem_map_memory(struct qcom_smem *smem, struct device *dev,
of_node_put(np);
if (ret)
return ret;
- size = resource_size(&r);
- smem->regions[i].virt_base = devm_ioremap_wc(dev, r.start, size);
- if (!smem->regions[i].virt_base)
- return -ENOMEM;
- smem->regions[i].aux_base = (u32)r.start;
- smem->regions[i].size = size;
+ region->aux_base = r.start;
+ region->size = resource_size(&r);
return 0;
}
@@ -895,12 +892,14 @@ static int qcom_smem_map_memory(struct qcom_smem *smem, struct device *dev,
static int qcom_smem_probe(struct platform_device *pdev)
{
struct smem_header *header;
+ struct reserved_mem *rmem;
struct qcom_smem *smem;
size_t array_size;
int num_regions;
int hwlock_id;
u32 version;
int ret;
+ int i;

Just a nitpicking, the index can be unsigned.

num_regions = 1;
if (of_find_property(pdev->dev.of_node, "qcom,rpm-msg-ram", NULL))
@@ -914,13 +913,35 @@ static int qcom_smem_probe(struct platform_device *pdev)
smem->dev = &pdev->dev;
smem->num_regions = num_regions;
- ret = qcom_smem_map_memory(smem, &pdev->dev, "memory-region", 0);
- if (ret)
- return ret;
+ rmem = of_reserved_mem_lookup(pdev->dev.of_node);
+ if (rmem) {
+ smem->regions[0].aux_base = rmem->base;
+ smem->regions[0].size = rmem->size;
+ } else {
+ /*
+ * Fall back to the memory-region reference, if we're not a
+ * reserved-memory node.
+ */
+ ret = qcom_smem_resolve_mem(smem, "memory-region", &smem->regions[0]);
+ if (ret)
+ return ret;
+ }
- if (num_regions > 1 && (ret = qcom_smem_map_memory(smem, &pdev->dev,
- "qcom,rpm-msg-ram", 1)))
- return ret;
+ if (num_regions > 1) {
+ ret = qcom_smem_resolve_mem(smem, "qcom,rpm-msg-ram", &smem->regions[1]);
+ if (ret)
+ return ret;
+ }
+
+ for (i = 0; i < num_regions; i++) {
+ smem->regions[i].virt_base = devm_ioremap_wc(&pdev->dev,
+ smem->regions[i].aux_base,
+ smem->regions[i].size);
+ if (!smem->regions[i].virt_base) {
+ dev_err(&pdev->dev, "failed to remap %pa\n", &smem->regions[i].aux_base);
+ return -ENOMEM;
+ }
+ }
header = smem->regions[0].virt_base;
if (le32_to_cpu(header->initialized) != 1 ||


--
Best wishes,
Vladimir