kernel: nvme: Add initial NVMe driver code

Signed-off-by: Ian Moffett <ian@osmora.org>

1 files changed, 367 insertions, 0 deletions

diff --git a/sys/dev/ic/nvme.c b/sys/dev/ic/nvme.c
new file mode 100644
index 0000000..b4ab531
--- /dev/null
+++ b/sys/dev/ic/nvme.c
@@ -0,0 +1,367 @@
+/*
+ * Copyright (c) 2023-2024 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/driver.h>
+#include <sys/cdefs.h>
+#include <sys/syslog.h>
+#include <sys/timer.h>
+#include <dev/pci/pci.h>
+#include <dev/ic/nvmevar.h>
+#include <vm/dynalloc.h>
+#include <vm/vm.h>
+#include <string.h>
+
+__MODULE_NAME("nvme");
+__KERNEL_META("$Hyra$: nvme.c, Ian Marco Moffett, "
+              "NVMe driver");
+
+#define COMMAND_SIZE 64     /* In bytes (defined by spec) */
+
+#define CAP_MPSMIN(caps) ((caps >> 48) & 0xF)
+#define CAP_MPSMAX(caps) ((caps >> 52) & 0xF)
+#define CAP_TIMEOUT(caps) ((caps >> 24) & 0xFF)
+#define CAP_STRIDE(caps) ((caps >> 32) & 0xF)
+#define CAP_MQES(caps) (caps & 0xFFFF)
+#define CAP_CSS(caps) (caps & 0xFF)
+
+#define STATUS_READY(status) (status & 1)
+
+#define CONFIG_EN   __BIT(0)
+#define CONFIG_CSS_SHIFT 4
+
+static struct pci_device *nvme_dev;
+static struct timer driver_tmr;
+
+static inline int
+is_4k_aligned(void *ptr)
+{
+    return ((uintptr_t)ptr & (0x1000 - 1)) == 0;
+}
+
+/*
+ * Poll CSTS.RDY to equal `val'
+ *
+ * Returns `val' on success, returns < 0 value
+ * upon failure.
+ */
+static int
+nvme_poll_ready(struct nvme_bar *bar, uint8_t val)
+{
+    uint8_t timeout = CAP_TIMEOUT(bar->caps);
+    uint8_t time_waited = 0;
+
+    do {
+        if (STATUS_READY(bar->status) == val) {
+            /* Done waiting */
+            break;
+        }
+
+        /*
+         * If CSTS.RDY hasn't changed, we can try to wait a
+         * little longer.
+         *
+         * XXX: The spec states that CAP.TO (Timeout) is in 500
+         *      millisecond units.
+         */
+        if (time_waited < timeout) {
+            driver_tmr.msleep(500);
+            ++time_waited;
+        } else {
+            return -1;
+        }
+    } while (1);
+
+    return val;
+}
+
+/*
+ * Create an admin queue.
+ */
+static int
+nvme_create_adminq(struct nvme_state *s, struct nvme_queue *queue)
+{
+    struct nvme_bar *bar = s->bar;
+    const size_t PAGESZ = vm_get_page_size();
+    const uint8_t DBSTRIDE = CAP_STRIDE(bar->caps);
+    const uint16_t SLOTS = CAP_MQES(bar->caps);
+
+    queue->sq = dynalloc_memalign(sizeof(void *) * SLOTS, 0x1000);
+    queue->cq = dynalloc_memalign(sizeof(void *) * SLOTS, 0x1000);
+
+    if (queue->sq == NULL) {
+        return -1;
+    }
+    if (queue->cq == NULL) {
+        dynfree(queue->sq);
+        return -1;
+    }
+
+    memset(queue->sq, 0, sizeof(void *) * SLOTS);
+    memset(queue->cq, 0, sizeof(void *) * SLOTS);
+
+    queue->sq_head = 0;
+    queue->sq_tail = 0;
+    queue->size = SLOTS;
+    queue->sq_db = PHYS_TO_VIRT((uintptr_t)bar + PAGESZ);
+    queue->cq_db = PHYS_TO_VIRT((uintptr_t)bar + PAGESZ + 1 * (4 << DBSTRIDE));
+    queue->cq_phase = 1;
+    return 0;
+}
+
+/*
+ * Submit a command
+ *
+ * @queue: Target queue.
+ * @cmd: Command to submit
+ */
+static void
+nvme_submit_cmd(struct nvme_queue *queue, struct nvme_cmd cmd)
+{
+    /* Submit the command to the queue */
+    queue->sq[queue->sq_tail++] = cmd;
+    if (queue->sq_tail >= queue->size) {
+        queue->sq_tail = 0;
+    }
+    *(queue->sq_db) = queue->sq_tail;
+}
+
+/*
+ * Submit a command and poll for completion
+ *
+ * @queue: Target queue.
+ * @cmd: Command to submit
+ */
+static int
+nvme_poll_submit_cmd(struct nvme_queue *queue, struct nvme_cmd cmd)
+{
+    uint16_t status;
+    size_t spins = 0;
+
+    nvme_submit_cmd(queue, cmd);
+
+    /*
+     * Wait for the current command to complete by
+     * polling the phase bit.
+     */
+    while (1) {
+        status = queue->cq[queue->cq_head].status;
+        if ((status & 1) == queue->cq_phase) {
+            /*
+             * The phase bit matches the phase for the most
+             * recently submitted command, the command has completed.
+             */
+            break;
+        }
+        if ((status & ~1) != 0) {
+            KDEBUG("NVMe cmd error (bits=0x%x)\n", status >> 1);
+            break;
+        }
+        if (spins > 5) {
+            /* Attempts exhausted */
+            KERR("Hang on phase bit poll, giving up (cmd error)\n");
+            break;
+        }
+
+        /* Not done, give it some more time */
+        driver_tmr.msleep(150);
+        ++spins;
+    }
+
+    ++queue->cq_head;
+    if (queue->cq_head >= queue->size) {
+        queue->cq_head = 0;
+        queue->cq_phase = !queue->cq_phase;
+    }
+
+    /* Tell the controller that `head' updated */
+    *(queue->cq_db) = queue->cq_head;
+    return 0;
+}
+
+/*
+ * Issue anidentify command for the current
+ * controller.
+ *
+ * XXX: `id' must be aligned on a 4k byte boundary to avoid
+ *      crossing a page boundary. This keeps the implementation
+ *      as simple as possible here.
+ */
+static int
+nvme_identify(struct nvme_state *state, struct nvme_id *id)
+{
+    struct nvme_cmd cmd = {0};
+    struct nvme_identify_cmd *identify = &cmd.identify;
+
+    /* Ensure `id' is aligned on a 4k byte boundary */
+    if (!is_4k_aligned(id)) {
+        return -1;
+    }
+
+    identify->opcode = NVME_OP_IDENTIFY;
+    identify->nsid = 0;
+    identify->cns = 1;   /* Identify controller */
+    identify->prp1 = VIRT_TO_PHYS(id);
+    identify->prp2 = 0;  /* No need, data address is 4k aligned */
+    nvme_poll_submit_cmd(&state->adminq, cmd);
+    return 0;
+}
+
+static int
+nvme_disable_controller(struct nvme_state *state)
+{
+    struct nvme_bar *bar = state->bar;
+
+    if (__TEST(bar->config, CONFIG_EN)) {
+        bar->config &= ~CONFIG_EN;
+    }
+
+    if (nvme_poll_ready(bar, 0) < 0) {
+        KERR("Failed to disable controller\n");
+        return -1;
+    }
+
+    return 0;
+}
+
+/*
+ * For debugging purposes, logs some information
+ * found within the controller identify data structure.
+ */
+static void
+nvme_log_ctrl_id(struct nvme_id *id)
+{
+    char mn[41] = {0};
+    char fr[9] = {0};
+
+    for (size_t i = 0; i < sizeof(id->mn); ++i) {
+        mn[i] = id->mn[i];
+    }
+    for (size_t i = 0; i < sizeof(id->fr); ++i) {
+        fr[i] = id->fr[i];
+    }
+
+    KDEBUG("NVMe model: %s\n", mn);
+    KDEBUG("NVMe firmware revision: %s\n", fr);
+}
+
+static int
+nvme_enable_controller(struct nvme_state *state)
+{
+    struct nvme_bar *bar = state->bar;
+    struct nvme_id *id;
+
+    if (!__TEST(bar->config, CONFIG_EN)) {
+        bar->config |= CONFIG_EN;
+    }
+
+    if (nvme_poll_ready(bar, 1) < 0) {
+        KERR("Failed to enable controller\n");
+    }
+
+    id = dynalloc_memalign(sizeof(struct nvme_id), 0x1000);
+
+    if (id == NULL) {
+        return -1;
+    }
+
+    nvme_identify(state, id);
+    nvme_log_ctrl_id(id);
+    dynfree(id);
+    return 0;
+}
+
+static int
+nvme_init_controller(struct nvme_bar *bar)
+{
+    struct nvme_state state = { . bar = bar };
+    struct nvme_queue *adminq = &state.adminq;
+
+    uint8_t cap_css = CAP_CSS(bar->caps);
+    uint16_t mqes = CAP_MQES(bar->caps);
+    uint16_t cmdreg_bits = PCI_BUS_MASTERING |
+                           PCI_MEM_SPACE;
+
+    pci_set_cmdreg(nvme_dev, cmdreg_bits);
+    nvme_disable_controller(&state);
+
+    nvme_create_adminq(&state, adminq);
+
+    /* Setup admin submission and admin completion queues */
+    bar->aqa = (mqes | mqes << 16);
+    bar->asq = VIRT_TO_PHYS(adminq->sq);
+    bar->acq = VIRT_TO_PHYS(adminq->cq);
+
+    /* Set up supported command sets */
+    if (__TEST(cap_css, __BIT(7))) {
+        /* Admin command sets only */
+        bar->config |= (7UL << CONFIG_CSS_SHIFT);
+    } else if (__TEST(cap_css, __BIT(6))) {
+        /* All supported I/O command sets */
+        bar->config |= (6UL << CONFIG_CSS_SHIFT);
+    }
+
+    nvme_enable_controller(&state);
+    return 0;
+}
+
+static int
+nvme_init(void)
+{
+    struct nvme_bar *bar;
+    struct pci_lookup nvme_lookup = {
+        .pci_class = 1,
+        .pci_subclass = 8
+    };
+
+    if (req_timer(TIMER_GP, &driver_tmr) != 0) {
+        KERR("Failed to fetch general purpose timer\n");
+        return -1;
+    }
+
+    if (driver_tmr.msleep == NULL) {
+        KERR("Timer does not have msleep()\n");
+        return -1;
+    }
+
+    nvme_dev = pci_get_device(nvme_lookup, PCI_CLASS | PCI_SUBCLASS);
+    if (nvme_dev == NULL) {
+        return -1;
+    }
+
+    bar = (struct nvme_bar *)(nvme_dev->bar[0] & ~7);
+    KINFO("NVMe BAR0 @ 0x%p\n", bar);
+
+    if (nvme_init_controller(bar) < 0) {
+        return -1;
+    }
+
+    return 0;
+}
+
+DRIVER_EXPORT(nvme_init);