tests/qtest/bcm2835-dma-test.c

   1 /*
   2  * QTest testcase for BCM283x DMA engine (on Raspberry Pi 3)
   3  * and its interrupts coming to Interrupt Controller.
   4  *
   5  * Copyright (c) 2022 Auriga LLC
   6  *
   7  * SPDX-License-Identifier: GPL-2.0-or-later
   8  */
   9
  10 #include "qemu/osdep.h"
  11 #include "libqtest-single.h"
  12
  13 /* Offsets in raspi3b platform: */
  14 #define RASPI3_DMA_BASE 0x3f007000
  15 #define RASPI3_IC_BASE  0x3f00b200
  16
  17 /* Used register/fields definitions */
  18
  19 /* DMA engine registers: */
  20 #define BCM2708_DMA_CS         0
  21 #define BCM2708_DMA_ACTIVE     (1 << 0)
  22 #define BCM2708_DMA_INT        (1 << 2)
  23
  24 #define BCM2708_DMA_ADDR       0x04
  25
  26 #define BCM2708_DMA_INT_STATUS 0xfe0
  27
  28 /* DMA Transfer Info fields: */
  29 #define BCM2708_DMA_INT_EN     (1 << 0)
  30 #define BCM2708_DMA_D_INC      (1 << 4)
  31 #define BCM2708_DMA_S_INC      (1 << 8)
  32
  33 /* Interrupt controller registers: */
  34 #define IRQ_PENDING_BASIC      0x00
  35 #define IRQ_GPU_PENDING1_AGGR  (1 << 8)
  36 #define IRQ_PENDING_1          0x04
  37 #define IRQ_ENABLE_1           0x10
  38
  39 /* Data for the test: */
  40 #define SCB_ADDR   256
  41 #define S_ADDR     32
  42 #define D_ADDR     64
  43 #define TXFR_LEN   32
  44 const uint32_t check_data = 0x12345678;
  45
  46 static void bcm2835_dma_test_interrupt(int dma_c, int irq_line)
  47 {
  48     uint64_t dma_base = RASPI3_DMA_BASE + dma_c * 0x100;
  49     int gpu_irq_line = 16 + irq_line;
  50
  51     /* Check that interrupts are silent by default: */
  52     writel(RASPI3_IC_BASE + IRQ_ENABLE_1, 1 << gpu_irq_line);
  53     int isr = readl(dma_base + BCM2708_DMA_INT_STATUS);
  54     g_assert_cmpint(isr, ==, 0);
  55     uint32_t reg0 = readl(dma_base + BCM2708_DMA_CS);
  56     g_assert_cmpint(reg0, ==, 0);
  57     uint32_t ic_pending = readl(RASPI3_IC_BASE + IRQ_PENDING_BASIC);
  58     g_assert_cmpint(ic_pending, ==, 0);
  59     uint32_t gpu_pending1 = readl(RASPI3_IC_BASE + IRQ_PENDING_1);
  60     g_assert_cmpint(gpu_pending1, ==, 0);
  61
  62     /* Prepare Control Block: */
  63     writel(SCB_ADDR + 0, BCM2708_DMA_S_INC | BCM2708_DMA_D_INC |
  64                          BCM2708_DMA_INT_EN); /* transfer info */
  65     writel(SCB_ADDR + 4, S_ADDR);             /* source address */
  66     writel(SCB_ADDR + 8, D_ADDR);             /* destination address */
  67     writel(SCB_ADDR + 12, TXFR_LEN);          /* transfer length */
  68     writel(dma_base + BCM2708_DMA_ADDR, SCB_ADDR);
  69
  70     writel(S_ADDR, check_data);
  71     for (int word = S_ADDR + 4; word < S_ADDR + TXFR_LEN; word += 4) {
  72         writel(word, ~check_data);
  73     }
  74     /* Perform the transfer: */
  75     writel(dma_base + BCM2708_DMA_CS, BCM2708_DMA_ACTIVE);
  76
  77     /* Check that destination == source: */
  78     uint32_t data = readl(D_ADDR);
  79     g_assert_cmpint(data, ==, check_data);
  80     for (int word = D_ADDR + 4; word < D_ADDR + TXFR_LEN; word += 4) {
  81         data = readl(word);
  82         g_assert_cmpint(data, ==, ~check_data);
  83     }
  84
  85     /* Check that interrupt status is set both in DMA and IC controllers: */
  86     isr = readl(RASPI3_DMA_BASE + BCM2708_DMA_INT_STATUS);
  87     g_assert_cmpint(isr, ==, 1 << dma_c);
  88
  89     ic_pending = readl(RASPI3_IC_BASE + IRQ_PENDING_BASIC);
  90     g_assert_cmpint(ic_pending, ==, IRQ_GPU_PENDING1_AGGR);
  91
  92     gpu_pending1 = readl(RASPI3_IC_BASE + IRQ_PENDING_1);
  93     g_assert_cmpint(gpu_pending1, ==, 1 << gpu_irq_line);
  94
  95     /* Clean up, clear interrupt: */
  96     writel(dma_base + BCM2708_DMA_CS, BCM2708_DMA_INT);
  97 }
  98
  99 static void bcm2835_dma_test_interrupts(void)
 100 {
 101     /* DMA engines 0--10 have separate IRQ lines, 11--14 - only one: */
 102     bcm2835_dma_test_interrupt(0,  0);
 103     bcm2835_dma_test_interrupt(10, 10);
 104     bcm2835_dma_test_interrupt(11, 11);
 105     bcm2835_dma_test_interrupt(14, 11);
 106 }
 107
 108 int main(int argc, char **argv)
 109 {
 110     int ret;
 111     g_test_init(&argc, &argv, NULL);
 112     qtest_add_func("/bcm2835/dma/test_interrupts",
 113                    bcm2835_dma_test_interrupts);
 114     qtest_start("-machine raspi3b");
 115     ret = g_test_run();
 116     qtest_end();
 117     return ret;
 118 }