kern: ahci: Add AHCI host bus adapter reset impl

This commit introduces this initial ahci_init() logic by resetting HBA
state on startup.

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

1 files changed, 136 insertions, 1 deletions

diff --git a/src/sys/io/ic/ahci.c b/src/sys/io/ic/ahci.c
index 4515b9d..3d0e890 100644
--- a/src/sys/io/ic/ahci.c
+++ b/src/sys/io/ic/ahci.c
@@ -35,8 +35,14 @@
 #include <sys/types.h>
 #include <sys/syslog.h>
 #include <sys/cdefs.h>
+#include <sys/errno.h>
 #include <io/pci/pci.h>
+#include <io/pci/bar.h>
+#include <io/ic/ahciregs.h>
+#include <io/ic/ahcivar.h>
 #include <os/module.h>
+#include <os/clkdev.h>
+#include <os/mmio.h>
 
 /*
  * Represents the PCI advocation descriptor for this
@@ -44,6 +50,107 @@
  */
 static struct pci_adv driver;
 
+/* Various other state */
+static struct pci_device dev;
+static struct clkdev *clkdev;
+static struct ahci_hba root_hba;
+
+/*
+ * Poll register to have 'bits' set/unset.
+ *
+ * @reg: Register to poll.
+ * @bits: Bits to be checked.
+ * @pollset: True to poll as set.
+ *
+ * Returns zero if the register updated in time, otherwise a less
+ * than zero value upon failure.
+ */
+static int
+ahci_poll32(volatile uint32_t *reg, uint32_t bits, bool pollset)
+{
+    size_t usec_start, usec;
+    size_t elapsed_msec;
+    uint32_t val;
+    bool tmp;
+
+    usec_start = clkdev->get_time_usec();
+    for (;;) {
+        val = mmio_read32(reg);
+        tmp = (pollset) ? ISSET(val, bits) : !ISSET(val, bits);
+
+        usec = clkdev->get_time_usec();
+        elapsed_msec = (usec - usec_start) / 1000;
+
+        /* If tmp is set, the register updated in time */
+        if (tmp) {
+            break;
+        }
+
+        /* Exit with an error if we timeout */
+        if (elapsed_msec > AHCI_TIMEOUT) {
+            return -ETIME;
+        }
+    }
+
+    return 0;
+}
+
+/*
+ * Perform a full HBA reset by using the HR bit
+ * within the GHC register.
+ *
+ * See section 10.4.3 of the AHCI spec for more
+ * information.
+ */
+static int
+ahci_hba_reset(struct ahci_hba *hba)
+{
+    volatile struct hba_memspace *io = hba->io;
+    uint32_t ghc;
+    int error;
+
+    /* Begin the reset */
+    ghc = mmio_read32(&io->ghc);
+    ghc |= AHCI_GHC_HR;
+    mmio_write32(&io->ghc, ghc);
+
+    /* Wait until it is done */
+    error = ahci_poll32(&io->ghc, AHCI_GHC_HR, false);
+    if (error < 0) {
+        printf("ahci: HBA reset timed out\n");
+        return error;
+    }
+
+    return 0;
+}
+
+/*
+ * Put the HBA as well as its devices in an initialized
+ * state so that they may be used for operation.
+ */
+static int
+ahci_hba_init(struct ahci_hba *hba)
+{
+    volatile struct hba_memspace *io = hba->io;
+    uint32_t ghc;
+    int error;
+
+    /* Ensure the host controller is AHCI aware */
+    ghc = mmio_read32(&io->ghc);
+    ghc |= AHCI_GHC_AE;
+    mmio_write32(&io->ghc, ghc);
+
+    /*
+     * We cannot be so certain what state the BIOS or whatever
+     * firmware left the host controller in, therefore the HBA
+     * will require a reset so we can have it in a known state.
+     */
+    if ((error = ahci_hba_reset(hba)) < 0) {
+        return error;
+    }
+    return 0;
+}
+
 /*
  * Initialize only the AHCI driver's state rather than
  * the hardware it covers. This is used so we can advertise
@@ -52,12 +159,22 @@ static struct pci_adv driver;
 static int
 ahci_init(struct module *modp)
 {
+    uint16_t clkmask;
     int error;
 
+    clkmask = CLKDEV_MSLEEP | CLKDEV_GET_USEC;
+    error = clkdev_get(clkmask, &clkdev);
+    if (error < 0) {
+        printf("ahci_init: could not get clkdev\n");
+        return error;
+    }
+
     if ((error = pci_advoc(&driver)) < 0) {
         printf("ahci_init: failed to advocate for HBA\n");
         return error;
     }
+
+    root_hba.io = NULL;
     return 0;
 }
 
@@ -68,8 +185,26 @@ ahci_init(struct module *modp)
 static int
 ahci_attach(struct pci_adv *adv)
 {
+    struct bus_space bs;
+    int error;
+
+    /* Only call once */
+    if (root_hba.io != NULL) {
+        return -EIO;
+    }
+
+    dev = adv->lookup;
     printf("ahci: detected AHCI controller\n");
-    return 0;
+
+    /* Map ABAR */
+    error = pci_map_bar(&dev, 5, &bs);
+    if (error < 0) {
+        printf("ahci: failed to map bar 5 (error=%d)\n", error);
+        return error;
+    }
+
+    root_hba.io = (void *)bs.va_base;
+    return ahci_hba_init(&root_hba);
 }
 
 static struct pci_adv driver = {