[PATCH v4 2/3] soc: qcom: rmtfs: Optionally map RMTFS to more VMs

[Konrad Dybcio <konrad.dybcio@linaro.org>]

From: Loic Poulain <loic.poulain@linaro.org>

Some SoCs require that RMTFS is also mapped to the NAV VM. Trying to
power on the modem without that results in the whole platform
crashing and forces a hard reboot within about 2 seconds. Add support
for mapping the region to additional VMs, such as NAV to open a path
towards enabling modem on such platforms.

Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
[Konrad: reword, make conditional and flexible, add a define for NAV VMID]
Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
---
v3 -> v4:
No changes

 drivers/soc/qcom/rmtfs_mem.c | 29 ++++++++++++++++++++++-------
 include/linux/qcom_scm.h     |  1 +
 2 files changed, 23 insertions(+), 7 deletions(-)

diff --git a/drivers/soc/qcom/rmtfs_mem.c b/drivers/soc/qcom/rmtfs_mem.c
index 0feaae357821..9d59ad509a5c 100644
--- a/drivers/soc/qcom/rmtfs_mem.c
+++ b/drivers/soc/qcom/rmtfs_mem.c
@@ -17,6 +17,7 @@
 #include <linux/qcom_scm.h>
 
 #define QCOM_RMTFS_MEM_DEV_MAX	(MINORMASK + 1)
+#define NUM_MAX_VMIDS		2
 
 static dev_t qcom_rmtfs_mem_major;
 
@@ -171,12 +172,12 @@ static void qcom_rmtfs_mem_release_device(struct device *dev)
 static int qcom_rmtfs_mem_probe(struct platform_device *pdev)
 {
 	struct device_node *node = pdev->dev.of_node;
-	struct qcom_scm_vmperm perms[2];
+	struct qcom_scm_vmperm perms[NUM_MAX_VMIDS + 1];
 	struct reserved_mem *rmem;
 	struct qcom_rmtfs_mem *rmtfs_mem;
 	u32 client_id;
-	u32 vmid;
-	int ret;
+	u32 num_vmids, vmid[NUM_MAX_VMIDS];
+	int ret, i;
 
 	rmem = of_reserved_mem_lookup(node);
 	if (!rmem) {
@@ -226,7 +227,18 @@ static int qcom_rmtfs_mem_probe(struct platform_device *pdev)
 		goto put_device;
 	}
 
-	ret = of_property_read_u32(node, "qcom,vmid", &vmid);
+	num_vmids = of_property_count_u32_elems(node, "qcom,vmid");
+	if (num_vmids < 0) {
+		dev_err(&pdev->dev, "failed to count qcom,vmid elements: %d\n", ret);
+		goto remove_cdev;
+	} else if (num_vmids > NUM_MAX_VMIDS) {
+		dev_warn(&pdev->dev,
+			 "too many VMIDs (%d) specified! Only mapping first %d entries\n",
+			 num_vmids, NUM_MAX_VMIDS);
+		num_vmids = NUM_MAX_VMIDS;
+	}
+
+	ret = of_property_read_u32_array(node, "qcom,vmid", vmid, num_vmids);
 	if (ret < 0 && ret != -EINVAL) {
 		dev_err(&pdev->dev, "failed to parse qcom,vmid\n");
 		goto remove_cdev;
@@ -238,12 +250,15 @@ static int qcom_rmtfs_mem_probe(struct platform_device *pdev)
 
 		perms[0].vmid = QCOM_SCM_VMID_HLOS;
 		perms[0].perm = QCOM_SCM_PERM_RW;
-		perms[1].vmid = vmid;
-		perms[1].perm = QCOM_SCM_PERM_RW;
+
+		for (i = 0; i < num_vmids; i++) {
+			perms[i + 1].vmid = vmid[i];
+			perms[i + 1].perm = QCOM_SCM_PERM_RW;
+		}
 
 		rmtfs_mem->perms = BIT(QCOM_SCM_VMID_HLOS);
 		ret = qcom_scm_assign_mem(rmtfs_mem->addr, rmtfs_mem->size,
-					  &rmtfs_mem->perms, perms, 2);
+					  &rmtfs_mem->perms, perms, num_vmids + 1);
 		if (ret < 0) {
 			dev_err(&pdev->dev, "assign memory failed\n");
 			goto remove_cdev;
diff --git a/include/linux/qcom_scm.h b/include/linux/qcom_scm.h
index f8335644a01a..150b72edb879 100644
--- a/include/linux/qcom_scm.h
+++ b/include/linux/qcom_scm.h
@@ -55,6 +55,7 @@ enum qcom_scm_ice_cipher {
 #define QCOM_SCM_VMID_MSS_MSA    0xF
 #define QCOM_SCM_VMID_WLAN       0x18
 #define QCOM_SCM_VMID_WLAN_CE    0x19
+#define QCOM_SCM_VMID_NAV        0x2B
 #define QCOM_SCM_PERM_READ       0x4
 #define QCOM_SCM_PERM_WRITE      0x2
 #define QCOM_SCM_PERM_EXEC       0x1
-- 
2.39.0