dart: add code to setup the DART iommu

Signed-off-by: Sven Peter <sven@svenpeter.dev>

Makefile

@@ -35,7 +35,7 @@ LIBFDT_OBJECTS := $(patsubst %,libfdt/%, \
 	fdt_addresses.o fdt_empty_tree.o fdt_ro.o fdt_rw.o fdt_strerror.o fdt_sw.o \
 	fdt_wip.o fdt.o)
 
-OBJECTS := adt.o bootlogo_128.o bootlogo_256.o chickens.o exception.o exception_asm.o fb.o \
+OBJECTS := adt.o bootlogo_128.o bootlogo_256.o chickens.o dart.o exception.o exception_asm.o fb.o \
 	heapblock.o kboot.o main.o memory.o memory_asm.o payload.o pmgr.o proxy.o smp.o start.o startup.o \
 	string.o tunables.o uart.o uartproxy.o utils.o utils_asm.o vsprintf.o wdt.o $(MINILZLIB_OBJECTS) \
 	$(TINF_OBJECTS) $(DLMALLOC_OBJECTS) $(LIBFDT_OBJECTS)

src/dart.c

@@ -0,0 +1,212 @@
+/* SPDX-License-Identifier: MIT */
+
+#include "assert.h"
+#include "dart.h"
+#include "malloc.h"
+#include "memory.h"
+#include "string.h"
+#include "utils.h"
+
+#define DART_CONFIG      0x60
+#define DART_CONFIG_LOCK BIT(15)
+
+#define DART_ERROR              0x40
+#define DART_ERROR_STREAM_SHIFT 24
+#define DART_ERROR_STREAM_MASK  0xf
+#define DART_ERROR_CODE_MASK    0xffffff
+#define DART_ERROR_FLAG         BIT(31)
+#define DART_ERROR_READ_FAULT   BIT(4)
+#define DART_ERROR_WRITE_FAULT  BIT(3)
+#define DART_ERROR_NO_PTE       BIT(2)
+#define DART_ERROR_NO_PMD       BIT(1)
+#define DART_ERROR_NO_TTBR      BIT(0)
+
+#define DART_STREAM_SELECT 0x34
+
+#define DART_STREAM_COMMAND            0x20
+#define DART_STREAM_COMMAND_BUSY       BIT(2)
+#define DART_STREAM_COMMAND_INVALIDATE BIT(20)
+
+#define DART_STREAM_COMMAND_BUSY_TIMEOUT 100
+
+#define DART_STREAM_REMAP 0x80
+
+#define DART_ERROR_ADDR_HI 0x54
+#define DART_ERROR_ADDR_LO 0x50
+
+#define DART_TCR(sid)             (0x100 + 4 * (sid))
+#define DART_TCR_TRANSLATE_ENABLE BIT(7)
+#define DART_TCR_BYPASS0_ENABLE   BIT(8)
+#define DART_TCR_BYPASS1_ENABLE   BIT(12)
+
+#define DART_TTBR(sid, idx) (0x200 + 16 * (sid) + 4 * (idx))
+#define DART_TTBR_VALID     BIT(31)
+#define DART_TTBR_SHIFT     12
+
+#define DART_PTE_VALID 0b11
+
+struct dart_dev {
+    uintptr_t regs;
+    u8 device;
+
+    u64 *l1;
+};
+
+static void dart_tlb_invalidate(dart_dev_t *dart)
+{
+    write32(dart->regs + DART_STREAM_SELECT, BIT(dart->device));
+
+    /* ensure that the DART can see the updated pagetables before invalidating */
+    dma_wmb();
+    write32(dart->regs + DART_STREAM_COMMAND, DART_STREAM_COMMAND_INVALIDATE);
+
+    if (poll32(dart->regs + DART_STREAM_COMMAND, DART_STREAM_COMMAND_BUSY, 0, 100))
+        printf("dart: DART_STREAM_COMMAND_BUSY did not clear.\n");
+}
+
+dart_dev_t *dart_init(uintptr_t base, u8 device)
+{
+    dart_dev_t *dart = malloc(sizeof(*dart));
+    if (!dart)
+        return NULL;
+
+    dart->regs = base;
+    dart->device = device;
+    dart->l1 = NULL;
+
+    if (read32(dart->regs + DART_CONFIG) & DART_CONFIG_LOCK) {
+        printf("dart: dart at %p is locked\n", dart->regs);
+        goto error;
+    }
+
+    dart->l1 = memalign(SZ_16K, 4 * SZ_16K);
+    if (!dart->l1)
+        goto error;
+    memset(dart->l1, 0, 4 * SZ_16K);
+
+    write32(dart->regs + DART_TTBR(device, 0),
+            DART_TTBR_VALID | (((uintptr_t)dart->l1) >> DART_TTBR_SHIFT));
+    write32(dart->regs + DART_TTBR(device, 1),
+            DART_TTBR_VALID | (((uintptr_t)dart->l1 + SZ_16K) >> DART_TTBR_SHIFT));
+    write32(dart->regs + DART_TTBR(device, 2),
+            DART_TTBR_VALID | (((uintptr_t)dart->l1 + 2 * SZ_16K) >> DART_TTBR_SHIFT));
+    write32(dart->regs + DART_TTBR(device, 3),
+            DART_TTBR_VALID | (((uintptr_t)dart->l1 + 3 * SZ_16K) >> DART_TTBR_SHIFT));
+
+    write32(dart->regs + DART_TCR(device), DART_TCR_TRANSLATE_ENABLE);
+    dart_tlb_invalidate(dart);
+
+    return dart;
+
+error:
+    free(dart->l1);
+    free(dart);
+    return NULL;
+}
+
+static u64 *dart_get_l2(dart_dev_t *dart, u32 idx)
+{
+    if (dart->l1[idx] & DART_PTE_VALID)
+        return (u64 *)(dart->l1[idx] & ~DART_PTE_VALID);
+
+    u64 *tbl = memalign(SZ_16K, SZ_16K);
+    if (!tbl)
+        return NULL;
+
+    memset(tbl, 0, SZ_16K);
+    dart->l1[idx] = (uintptr_t)tbl | DART_PTE_VALID;
+    return tbl;
+}
+
+static int dart_map_page(dart_dev_t *dart, uintptr_t iova, uintptr_t paddr)
+{
+    u32 l1_index = (iova >> 25) & 0x1fff;
+    u32 l2_index = (iova >> 14) & 0x7ff;
+
+    u64 *l2 = dart_get_l2(dart, l1_index);
+    if (!l2) {
+        printf("dart: couldn't create l2 for iova %llx\n", iova);
+        return -1;
+    }
+
+    if (l2[l2_index] & DART_PTE_VALID) {
+        printf("dart: iova %llx already has a valid PTE: %llx\n", iova, l2[l2_index]);
+        return -1;
+    }
+
+    l2[l2_index] = (uintptr_t)paddr | DART_PTE_VALID;
+
+    return 0;
+}
+
+int dart_map(dart_dev_t *dart, uintptr_t iova, void *bfr, size_t len)
+{
+    uintptr_t paddr = (uintptr_t)bfr;
+    u64 offset = 0;
+
+    if (len % SZ_16K)
+        return -1;
+    if (paddr % SZ_16K)
+        return -1;
+    if (iova % SZ_16K)
+        return -1;
+
+    while (offset < len) {
+        int ret = dart_map_page(dart, iova + offset, paddr + offset);
+
+        if (ret) {
+            dart_unmap(dart, iova, offset);
+            return ret;
+        }
+
+        offset += SZ_16K;
+    }
+
+    dart_tlb_invalidate(dart);
+    return 0;
+}
+
+static void dart_unmap_page(dart_dev_t *dart, uintptr_t iova)
+{
+    u32 l1_index = (iova >> 25) & 0x1fff;
+    u32 l2_index = (iova >> 14) & 0x7ff;
+
+    if (!(dart->l1[l1_index] & DART_PTE_VALID))
+        return;
+
+    u64 *l2 = (u64 *)(dart->l1[l1_index] & ~DART_PTE_VALID);
+    l2[l2_index] = 0;
+}
+
+void dart_unmap(dart_dev_t *dart, uintptr_t iova, size_t len)
+{
+    if (len % SZ_16K)
+        return;
+    if (iova % SZ_16K)
+        return;
+
+    while (len) {
+        dart_unmap_page(dart, iova);
+
+        len -= SZ_16K;
+        iova += SZ_16K;
+    }
+
+    dart_tlb_invalidate(dart);
+}
+
+void dart_shutdown(dart_dev_t *dart)
+{
+    write32(dart->regs + DART_TCR(dart->device), 0);
+    for (int i = 0; i < 4; ++i)
+        write32(dart->regs + DART_TTBR(dart->device, i), 0);
+    dart_tlb_invalidate(dart);
+
+    for (int i = 0; i < SZ_16K / 8; ++i) {
+        if (dart->l1[i] & DART_PTE_VALID)
+            free((void *)(dart->l1[i] & ~DART_PTE_VALID));
+    }
+
+    free(dart->l1);
+    free(dart);
+}

src/dart.h

@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: MIT */
+
+#ifndef DART_H
+#define DART_H
+
+#include "types.h"
+
+typedef struct dart_dev dart_dev_t;
+
+dart_dev_t *dart_init(uintptr_t base, u8 device);
+int dart_map(dart_dev_t *dart, uintptr_t iova, void *bfr, size_t len);
+void dart_unmap(dart_dev_t *dart, uintptr_t iova, size_t len);
+void dart_shutdown(dart_dev_t *dart);
+
+#endif