1 files changed, 116 insertions, 0 deletions

diff --git a/drivers/net/ipa/ipa_mem.c b/drivers/net/ipa/ipa_mem.c
index 3c0916597fe1..aa8f6b0f3d50 100644
--- a/drivers/net/ipa/ipa_mem.c
+++ b/drivers/net/ipa/ipa_mem.c
@@ -10,6 +10,7 @@
 #include <linux/dma-mapping.h>
 #include <linux/iommu.h>
 #include <linux/io.h>
+#include <linux/soc/qcom/smem.h>
 
 #include "ipa.h"
 #include "ipa_reg.h"
@@ -23,6 +24,9 @@
 /* "Canary" value placed between memory regions to detect overflow */
 #define IPA_MEM_CANARY_VAL		cpu_to_le32(0xdeadbeef)
 
+/* SMEM host id representing the modem. */
+#define QCOM_SMEM_HOST_MODEM	1
+
 /* Add an immediate command to a transaction that zeroes a memory region */
 static void
 ipa_mem_zero_region_add(struct gsi_trans *trans, const struct ipa_mem *mem)
@@ -340,6 +344,111 @@ static void ipa_imem_exit(struct ipa *ipa)
 	ipa->imem_iova = 0;
 }
 
+/**
+ * ipa_smem_init() - Initialize SMEM memory used by the IPA
+ * @ipa:	IPA pointer
+ * @item:	Item ID of SMEM memory
+ * @size:	Size (bytes) of SMEM memory region
+ *
+ * SMEM is a managed block of shared DRAM, from which numbered "items"
+ * can be allocated.  One item is designated for use by the IPA.
+ *
+ * The modem accesses SMEM memory directly, but the IPA accesses it
+ * via the IOMMU, using the AP's credentials.
+ *
+ * If size provided is non-zero, we allocate it and map it for
+ * access through the IOMMU.
+ *
+ * Note: @size and the item address are is not guaranteed to be page-aligned.
+ */
+static int ipa_smem_init(struct ipa *ipa, u32 item, size_t size)
+{
+	struct device *dev = &ipa->pdev->dev;
+	struct iommu_domain *domain;
+	unsigned long iova;
+	phys_addr_t phys;
+	phys_addr_t addr;
+	size_t actual;
+	void *virt;
+	int ret;
+
+	if (!size)
+		return 0;	/* SMEM memory not used */
+
+	/* SMEM is memory shared between the AP and another system entity
+	 * (in this case, the modem).  An allocation from SMEM is persistent
+	 * until the AP reboots; there is no way to free an allocated SMEM
+	 * region.  Allocation only reserves the space; to use it you need
+	 * to "get" a pointer it (this implies no reference counting).
+	 * The item might have already been allocated, in which case we
+	 * use it unless the size isn't what we expect.
+	 */
+	ret = qcom_smem_alloc(QCOM_SMEM_HOST_MODEM, item, size);
+	if (ret && ret != -EEXIST) {
+		dev_err(dev, "error %d allocating size %zu SMEM item %u\n",
+			ret, size, item);
+		return ret;
+	}
+
+	/* Now get the address of the SMEM memory region */
+	virt = qcom_smem_get(QCOM_SMEM_HOST_MODEM, item, &actual);
+	if (IS_ERR(virt)) {
+		ret = PTR_ERR(virt);
+		dev_err(dev, "error %d getting SMEM item %u\n", ret, item);
+		return ret;
+	}
+
+	/* In case the region was already allocated, verify the size */
+	if (ret && actual != size) {
+		dev_err(dev, "SMEM item %u has size %zu, expected %zu\n",
+			item, actual, size);
+		return -EINVAL;
+	}
+
+	domain = iommu_get_domain_for_dev(dev);
+	if (!domain) {
+		dev_err(dev, "no IOMMU domain found for SMEM\n");
+		return -EINVAL;
+	}
+
+	/* Align the address down and the size up to a page boundary */
+	addr = qcom_smem_virt_to_phys(virt) & PAGE_MASK;
+	phys = addr & PAGE_MASK;
+	size = PAGE_ALIGN(size + addr - phys);
+	iova = phys;	/* We just want a direct mapping */
+
+	ret = iommu_map(domain, iova, phys, size, IOMMU_READ | IOMMU_WRITE);
+	if (ret)
+		return ret;
+
+	ipa->smem_iova = iova;
+	ipa->smem_size = size;
+
+	return 0;
+}
+
+static void ipa_smem_exit(struct ipa *ipa)
+{
+	struct device *dev = &ipa->pdev->dev;
+	struct iommu_domain *domain;
+
+	domain = iommu_get_domain_for_dev(dev);
+	if (domain) {
+		size_t size;
+
+		size = iommu_unmap(domain, ipa->smem_iova, ipa->smem_size);
+		if (size != ipa->smem_size)
+			dev_warn(dev, "unmapped %zu SMEM bytes, expected %lu\n",
+				 size, ipa->smem_size);
+
+	} else {
+		dev_err(dev, "couldn't get IPA IOMMU domain for SMEM\n");
+	}
+
+	ipa->smem_size = 0;
+	ipa->smem_iova = 0;
+}
+
 /* Perform memory region-related initialization */
 int ipa_mem_init(struct ipa *ipa, const struct ipa_mem_data *mem_data)
 {
@@ -383,8 +492,14 @@ int ipa_mem_init(struct ipa *ipa, const struct ipa_mem_data *mem_data)
 	if (ret)
 		goto err_unmap;
 
+	ret = ipa_smem_init(ipa, mem_data->smem_id, mem_data->smem_size);
+	if (ret)
+		goto err_imem_exit;
+
 	return 0;
 
+err_imem_exit:
+	ipa_imem_exit(ipa);
 err_unmap:
 	memunmap(ipa->mem_virt);
 
@@ -394,6 +509,7 @@ err_unmap:
 /* Inverse of ipa_mem_init() */
 void ipa_mem_exit(struct ipa *ipa)
 {
+	ipa_smem_exit(ipa);
 	ipa_imem_exit(ipa);
 	memunmap(ipa->mem_virt);
 }