[PATCH v6 2/6] platform/x86/amd/hsmp: Map the metric table with ioremap() and unmap it explicitly

[Muralidhara M K <muralidhara.mk@amd.com>]

The metric-table DRAM region is mapped with devm_ioremap(), which ties the
mapping to the socket device's devres scope. An upcoming change lets the
ACPI front-end share the socket array across sockets and run its own
coordinated teardown, so the mapping can no longer be pinned to a single
per-socket devres scope.

Map it with plain ioremap() instead and add hsmp_unmap_metric_tbls(), which
drops every socket's metric_tbl_addr mapping. The platform driver registers
that helper with devm_add_action_or_reset() so the mappings are released on
both remove and probe failure, while the socket array itself stays
devm-managed.

Signed-off-by: Muralidhara M K <muralidhara.mk@amd.com>
---
 drivers/platform/x86/amd/hsmp/hsmp.c | 19 +++++++++++++++++--
 drivers/platform/x86/amd/hsmp/hsmp.h |  1 +
 drivers/platform/x86/amd/hsmp/plat.c | 17 +++++++++++++++++
 3 files changed, 35 insertions(+), 2 deletions(-)

diff --git a/drivers/platform/x86/amd/hsmp/hsmp.c b/drivers/platform/x86/amd/hsmp/hsmp.c
index e9c17698983c..008f3c0b2ad7 100644
--- a/drivers/platform/x86/amd/hsmp/hsmp.c
+++ b/drivers/platform/x86/amd/hsmp/hsmp.c
@@ -12,6 +12,7 @@
 #include <linux/acpi.h>
 #include <linux/delay.h>
 #include <linux/device.h>
+#include <linux/io.h>
 #include <linux/rwsem.h>
 #include <linux/semaphore.h>
 #include <linux/sysfs.h>
@@ -423,6 +424,21 @@ ssize_t hsmp_metric_tbl_read(struct hsmp_socket *sock, char *buf, size_t size)
 }
 EXPORT_SYMBOL_NS_GPL(hsmp_metric_tbl_read, "AMD_HSMP");
 
+void hsmp_unmap_metric_tbls(struct hsmp_plat_device *pdev)
+{
+	struct hsmp_socket *sock;
+	u16 i;
+
+	for (i = 0; i < pdev->num_sockets; i++) {
+		sock = &pdev->sock[i];
+		if (sock->metric_tbl_addr) {
+			iounmap(sock->metric_tbl_addr);
+			sock->metric_tbl_addr = NULL;
+		}
+	}
+}
+EXPORT_SYMBOL_NS_GPL(hsmp_unmap_metric_tbls, "AMD_HSMP");
+
 int hsmp_get_tbl_dram_base(u16 sock_ind)
 {
 	struct hsmp_socket *sock = &hsmp_pdev.sock[sock_ind];
@@ -447,8 +463,7 @@ int hsmp_get_tbl_dram_base(u16 sock_ind)
 		dev_err(sock->dev, "Invalid DRAM address for metric table\n");
 		return -ENOMEM;
 	}
-	sock->metric_tbl_addr = devm_ioremap(sock->dev, dram_addr,
-					     sizeof(struct hsmp_metric_table));
+	sock->metric_tbl_addr = ioremap(dram_addr, sizeof(struct hsmp_metric_table));
 	if (!sock->metric_tbl_addr) {
 		dev_err(sock->dev, "Failed to ioremap metric table addr\n");
 		return -ENOMEM;
diff --git a/drivers/platform/x86/amd/hsmp/hsmp.h b/drivers/platform/x86/amd/hsmp/hsmp.h
index 129200d0cf81..b0d67b93363d 100644
--- a/drivers/platform/x86/amd/hsmp/hsmp.h
+++ b/drivers/platform/x86/amd/hsmp/hsmp.h
@@ -64,6 +64,7 @@ long hsmp_ioctl(struct file *fp, unsigned int cmd, unsigned long arg);
 void hsmp_misc_deregister(void);
 int hsmp_misc_register(struct device *dev);
 int hsmp_get_tbl_dram_base(u16 sock_ind);
+void hsmp_unmap_metric_tbls(struct hsmp_plat_device *pdev);
 ssize_t hsmp_metric_tbl_read(struct hsmp_socket *sock, char *buf, size_t size);
 struct hsmp_plat_device *get_hsmp_pdev(void);
 #if IS_ENABLED(CONFIG_HWMON)
diff --git a/drivers/platform/x86/amd/hsmp/plat.c b/drivers/platform/x86/amd/hsmp/plat.c
index e07f68575055..b5f2120765c8 100644
--- a/drivers/platform/x86/amd/hsmp/plat.c
+++ b/drivers/platform/x86/amd/hsmp/plat.c
@@ -201,6 +201,19 @@ static int init_platform_device(struct device *dev)
 	return 0;
 }
 
+/*
+ * The socket array is devm-managed and freed by the driver core, but the
+ * metric-table DRAM regions are mapped with plain ioremap() during probe and
+ * are therefore not covered by devres.
+ *
+ * Drop those mappings from a devres action so both remove and probe failure
+ * unmap them exactly once, before the socket array they refer to is freed.
+ */
+static void hsmp_pltdrv_release(void *data)
+{
+	hsmp_unmap_metric_tbls(hsmp_pdev);
+}
+
 static int hsmp_pltdrv_probe(struct platform_device *pdev)
 {
 	int ret;
@@ -211,6 +224,10 @@ static int hsmp_pltdrv_probe(struct platform_device *pdev)
 	if (!hsmp_pdev->sock)
 		return -ENOMEM;
 
+	ret = devm_add_action_or_reset(&pdev->dev, hsmp_pltdrv_release, NULL);
+	if (ret)
+		return ret;
+
 	ret = init_platform_device(&pdev->dev);
 	if (ret) {
 		dev_err(&pdev->dev, "Failed to init HSMP mailbox\n");
-- 
2.34.1