linux-kernel - [PATCH v2 1/2] mlxbf-bootctl: Support the large icmc write/read

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Message-ID: <20230809162857.21243-2-asmaa@nvidia.com>
Date:   Wed, 9 Aug 2023 12:28:56 -0400
From:   Asmaa Mnebhi <asmaa@...dia.com>
To:     <markgross@...nel.org>, <vadimp@...dia.com>, <hdegoede@...hat.com>,
        <linux-kernel@...r.kernel.org>
CC:     Asmaa Mnebhi <asmaa@...dia.com>
Subject: [PATCH v2 1/2] mlxbf-bootctl: Support the large icmc write/read

Enable reading and writing the size of the memory region associated
with the large ICM carveout.
The max size of the large ICM carveout is 1TB, has a granularity
of 128MB and will be passed and printed in hex. The size unit is MB.

Signed-off-by: Asmaa Mnebhi <asmaa@...dia.com>
---
v1->v2:
- added defines for icmc related integers
- removed unnecessary parentheses.

 drivers/platform/mellanox/mlxbf-bootctl.c | 42 +++++++++++++++++++++++
 drivers/platform/mellanox/mlxbf-bootctl.h | 14 ++++++++
 2 files changed, 56 insertions(+)

diff --git a/drivers/platform/mellanox/mlxbf-bootctl.c b/drivers/platform/mellanox/mlxbf-bootctl.c
index fb9f7815c6cd..52d1272478a4 100644
--- a/drivers/platform/mellanox/mlxbf-bootctl.c
+++ b/drivers/platform/mellanox/mlxbf-bootctl.c
@@ -79,6 +79,8 @@ static void __iomem *mlxbf_rsh_scratch_buf_data;
 static const char * const mlxbf_rsh_log_level[] = {
 	"INFO", "WARN", "ERR", "ASSERT"};
 
+static DEFINE_MUTEX(icm_ops_lock);
+
 /* ARM SMC call which is atomic and no need for lock. */
 static int mlxbf_bootctl_smc(unsigned int smc_op, int smc_arg)
 {
@@ -391,6 +393,44 @@ static ssize_t rsh_log_store(struct device *dev,
 	return count;
 }
 
+static ssize_t large_icm_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct arm_smccc_res res;
+
+	mutex_lock(&icm_ops_lock);
+	arm_smccc_smc(MLNX_HANDLE_GET_ICM_INFO, 0, 0, 0, 0,
+		      0, 0, 0, &res);
+	mutex_unlock(&icm_ops_lock);
+	if (res.a0)
+		return -EPERM;
+
+	return snprintf(buf, PAGE_SIZE, "0x%lx", res.a1);
+}
+
+static ssize_t large_icm_store(struct device *dev,
+			       struct device_attribute *attr,
+			       const char *buf, size_t count)
+{
+	struct arm_smccc_res res;
+	unsigned long icm_data;
+	int err;
+
+	err = kstrtoul(buf, MLXBF_LARGE_ICMC_MAX_STRING_SIZE, &icm_data);
+	if (err)
+		return err;
+
+	if ((icm_data != 0 && icm_data < MLXBF_LARGE_ICMC_SIZE_MIN) ||
+	    icm_data > MLXBF_LARGE_ICMC_SIZE_MAX || icm_data % MLXBF_LARGE_ICMC_GRANULARITY)
+		return -EPERM;
+
+	mutex_lock(&icm_ops_lock);
+	arm_smccc_smc(MLNX_HANDLE_SET_ICM_INFO, icm_data, 0, 0, 0, 0, 0, 0, &res);
+	mutex_unlock(&icm_ops_lock);
+
+	return res.a0 ? -EPERM : count;
+}
+
 static DEVICE_ATTR_RW(post_reset_wdog);
 static DEVICE_ATTR_RW(reset_action);
 static DEVICE_ATTR_RW(second_reset_action);
@@ -398,6 +438,7 @@ static DEVICE_ATTR_RO(lifecycle_state);
 static DEVICE_ATTR_RO(secure_boot_fuse_state);
 static DEVICE_ATTR_WO(fw_reset);
 static DEVICE_ATTR_WO(rsh_log);
+static DEVICE_ATTR_RW(large_icm);
 
 static struct attribute *mlxbf_bootctl_attrs[] = {
 	&dev_attr_post_reset_wdog.attr,
@@ -407,6 +448,7 @@ static struct attribute *mlxbf_bootctl_attrs[] = {
 	&dev_attr_secure_boot_fuse_state.attr,
 	&dev_attr_fw_reset.attr,
 	&dev_attr_rsh_log.attr,
+	&dev_attr_large_icm.attr,
 	NULL
 };
 
diff --git a/drivers/platform/mellanox/mlxbf-bootctl.h b/drivers/platform/mellanox/mlxbf-bootctl.h
index b48243f60a59..fc5019c90fc5 100644
--- a/drivers/platform/mellanox/mlxbf-bootctl.h
+++ b/drivers/platform/mellanox/mlxbf-bootctl.h
@@ -81,6 +81,15 @@
  */
 #define MLXBF_BOOTCTL_FW_RESET  0x8200000D
 
+/*
+ * SMC function IDs to set and get the large ICM carveout size
+ * stored in the eeprom.
+ */
+#define MLNX_HANDLE_SET_ICM_INFO    0x82000012
+#define MLNX_HANDLE_GET_ICM_INFO    0x82000013
+
+#define MAX_ICM_BUFFER_SIZE 10
+
 /* SMC function IDs for SiP Service queries */
 #define MLXBF_BOOTCTL_SIP_SVC_CALL_COUNT	0x8200ff00
 #define MLXBF_BOOTCTL_SIP_SVC_UID		0x8200ff01
@@ -106,4 +115,9 @@
 /* Additional value to disable the MLXBF_BOOTCTL_SET_SECOND_RESET_ACTION. */
 #define MLXBF_BOOTCTL_NONE	0x7fffffff /* Don't change next boot action */
 
+#define MLXBF_LARGE_ICMC_MAX_STRING_SIZE 16
+#define MLXBF_LARGE_ICMC_SIZE_MIN        0x80
+#define MLXBF_LARGE_ICMC_SIZE_MAX        0x100000
+#define MLXBF_LARGE_ICMC_GRANULARITY     MLXBF_LARGE_ICMC_SIZE_MIN
+
 #endif /* __MLXBF_BOOTCTL_H__ */
-- 
2.30.1