[PATCH] libata: improve driver initialization and deinitialization

Implement ahci_[de]init_port() and use it during initialization and
de-initialization.  ahci_[de]init_port() are supersets of what used to
be done during driver [de-]initialization.  This patch makes the
following behavior changes.

* Per-port IRQ mask is cleared on driver load as done in other
  drivers.  The mask will be configured properly during probe.

* During init_one(), HOST_IRQ_STAT is cleared after masking port IRQs
  such that there is no race window.

* CMD_SPIN_UP is cleared during init_one() instead of being set.  It
  is set in port_start().  This is more consistent with overall
  structure of initialization.  Note that CMD_SPIN_UP simply controls
  PHY activation.

* Slumber and staggered spin-up are handled properly.

* All init/deinit operations are done in step-by-step manner as
  described in the spec instead of issued as single merged command.

Original implementation is from Zhao, Forrest <forrest.zhao@intel.com>

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Zhao, Forrest <forrest.zhao@intel.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 151 insertions, 51 deletions

diff --git a/drivers/scsi/ahci.c b/drivers/scsi/ahci.c
index e02b9c65287b..fb71fa7bc5de 100644
--- a/drivers/scsi/ahci.c
+++ b/drivers/scsi/ahci.c
@@ -92,7 +92,9 @@ enum {
         HOST_AHCI_EN            = (1 << 31), /* AHCI enabled */
 
         /* HOST_CAP bits */
+        HOST_CAP_SSC            = (1 << 14), /* Slumber capable */
         HOST_CAP_CLO            = (1 << 24), /* Command List Override support */
+        HOST_CAP_SSS            = (1 << 27), /* Staggered Spin-up */
         HOST_CAP_NCQ            = (1 << 30), /* Native Command Queueing */
         HOST_CAP_64             = (1 << 31), /* PCI DAC (64-bit DMA) support */
 
@@ -155,6 +157,7 @@ enum {
         PORT_CMD_SPIN_UP        = (1 << 1), /* Spin up device */
         PORT_CMD_START          = (1 << 0), /* Enable port DMA engine */
 
+        PORT_CMD_ICC_MASK       = (0xf << 28), /* i/f ICC state mask */
         PORT_CMD_ICC_ACTIVE     = (0x1 << 28), /* Put i/f in active state */
         PORT_CMD_ICC_PARTIAL    = (0x2 << 28), /* Put i/f in partial state */
         PORT_CMD_ICC_SLUMBER    = (0x6 << 28), /* Put i/f in slumber state */
@@ -440,6 +443,135 @@ static int ahci_stop_engine(void __iomem *port_mmio)
         return 0;
 }
 
+static void ahci_start_fis_rx(void __iomem *port_mmio, u32 cap,
+                              dma_addr_t cmd_slot_dma, dma_addr_t rx_fis_dma)
+{
+        u32 tmp;
+
+        /* set FIS registers */
+        if (cap & HOST_CAP_64)
+                writel((cmd_slot_dma >> 16) >> 16, port_mmio + PORT_LST_ADDR_HI);
+        writel(cmd_slot_dma & 0xffffffff, port_mmio + PORT_LST_ADDR);
+
+        if (cap & HOST_CAP_64)
+                writel((rx_fis_dma >> 16) >> 16, port_mmio + PORT_FIS_ADDR_HI);
+        writel(rx_fis_dma & 0xffffffff, port_mmio + PORT_FIS_ADDR);
+
+        /* enable FIS reception */
+        tmp = readl(port_mmio + PORT_CMD);
+        tmp |= PORT_CMD_FIS_RX;
+        writel(tmp, port_mmio + PORT_CMD);
+
+        /* flush */
+        readl(port_mmio + PORT_CMD);
+}
+
+static int ahci_stop_fis_rx(void __iomem *port_mmio)
+{
+        u32 tmp;
+
+        /* disable FIS reception */
+        tmp = readl(port_mmio + PORT_CMD);
+        tmp &= ~PORT_CMD_FIS_RX;
+        writel(tmp, port_mmio + PORT_CMD);
+
+        /* wait for completion, spec says 500ms, give it 1000 */
+        tmp = ata_wait_register(port_mmio + PORT_CMD, PORT_CMD_FIS_ON,
+                                PORT_CMD_FIS_ON, 10, 1000);
+        if (tmp & PORT_CMD_FIS_ON)
+                return -EBUSY;
+
+        return 0;
+}
+
+static void ahci_power_up(void __iomem *port_mmio, u32 cap)
+{
+        u32 cmd;
+
+        cmd = readl(port_mmio + PORT_CMD) & ~PORT_CMD_ICC_MASK;
+
+        /* spin up device */
+        if (cap & HOST_CAP_SSS) {
+                cmd |= PORT_CMD_SPIN_UP;
+                writel(cmd, port_mmio + PORT_CMD);
+        }
+
+        /* wake up link */
+        writel(cmd | PORT_CMD_ICC_ACTIVE, port_mmio + PORT_CMD);
+}
+
+static void ahci_power_down(void __iomem *port_mmio, u32 cap)
+{
+        u32 cmd, scontrol;
+
+        cmd = readl(port_mmio + PORT_CMD) & ~PORT_CMD_ICC_MASK;
+
+        if (cap & HOST_CAP_SSC) {
+                /* enable transitions to slumber mode */
+                scontrol = readl(port_mmio + PORT_SCR_CTL);
+                if ((scontrol & 0x0f00) > 0x100) {
+                        scontrol &= ~0xf00;
+                        writel(scontrol, port_mmio + PORT_SCR_CTL);
+                }
+
+                /* put device into slumber mode */
+                writel(cmd | PORT_CMD_ICC_SLUMBER, port_mmio + PORT_CMD);
+
+                /* wait for the transition to complete */
+                ata_wait_register(port_mmio + PORT_CMD, PORT_CMD_ICC_SLUMBER,
+                                  PORT_CMD_ICC_SLUMBER, 1, 50);
+        }
+
+        /* put device into listen mode */
+        if (cap & HOST_CAP_SSS) {
+                /* first set PxSCTL.DET to 0 */
+                scontrol = readl(port_mmio + PORT_SCR_CTL);
+                scontrol &= ~0xf;
+                writel(scontrol, port_mmio + PORT_SCR_CTL);
+
+                /* then set PxCMD.SUD to 0 */
+                cmd &= ~PORT_CMD_SPIN_UP;
+                writel(cmd, port_mmio + PORT_CMD);
+        }
+}
+
+static void ahci_init_port(void __iomem *port_mmio, u32 cap,
+                           dma_addr_t cmd_slot_dma, dma_addr_t rx_fis_dma)
+{
+        /* power up */
+        ahci_power_up(port_mmio, cap);
+
+        /* enable FIS reception */
+        ahci_start_fis_rx(port_mmio, cap, cmd_slot_dma, rx_fis_dma);
+
+        /* enable DMA */
+        ahci_start_engine(port_mmio);
+}
+
+static int ahci_deinit_port(void __iomem *port_mmio, u32 cap, const char **emsg)
+{
+        int rc;
+
+        /* disable DMA */
+        rc = ahci_stop_engine(port_mmio);
+        if (rc) {
+                *emsg = "failed to stop engine";
+                return rc;
+        }
+
+        /* disable FIS reception */
+        rc = ahci_stop_fis_rx(port_mmio);
+        if (rc) {
+                *emsg = "failed stop FIS RX";
+                return rc;
+        }
+
+        /* put device into slumber mode */
+        ahci_power_down(port_mmio, cap);
+
+        return 0;
+}
+
 static unsigned int ahci_dev_classify(struct ata_port *ap)
 {
         void __iomem *port_mmio = (void __iomem *) ap->ioaddr.cmd_addr;
@@ -1037,20 +1169,8 @@ static int ahci_port_start(struct ata_port *ap)
 
         ap->private_data = pp;
 
-        if (hpriv->cap & HOST_CAP_64)
-                writel((pp->cmd_slot_dma >> 16) >> 16, port_mmio + PORT_LST_ADDR_HI);
-        writel(pp->cmd_slot_dma & 0xffffffff, port_mmio + PORT_LST_ADDR);
-        readl(port_mmio + PORT_LST_ADDR); /* flush */
-
-        if (hpriv->cap & HOST_CAP_64)
-                writel((pp->rx_fis_dma >> 16) >> 16, port_mmio + PORT_FIS_ADDR_HI);
-        writel(pp->rx_fis_dma & 0xffffffff, port_mmio + PORT_FIS_ADDR);
-        readl(port_mmio + PORT_FIS_ADDR); /* flush */
-
-        writel(PORT_CMD_ICC_ACTIVE | PORT_CMD_FIS_RX |
-               PORT_CMD_POWER_ON | PORT_CMD_SPIN_UP |
-               PORT_CMD_START, port_mmio + PORT_CMD);
-        readl(port_mmio + PORT_CMD); /* flush */
+        /* initialize port */
+        ahci_init_port(port_mmio, hpriv->cap, pp->cmd_slot_dma, pp->rx_fis_dma);
 
         return 0;
 }
@@ -1058,20 +1178,17 @@ static int ahci_port_start(struct ata_port *ap)
 static void ahci_port_stop(struct ata_port *ap)
 {
         struct device *dev = ap->host_set->dev;
+        struct ahci_host_priv *hpriv = ap->host_set->private_data;
         struct ahci_port_priv *pp = ap->private_data;
         void __iomem *mmio = ap->host_set->mmio_base;
         void __iomem *port_mmio = ahci_port_base(mmio, ap->port_no);
-        u32 tmp;
-
-        tmp = readl(port_mmio + PORT_CMD);
-        tmp &= ~(PORT_CMD_START | PORT_CMD_FIS_RX);
-        writel(tmp, port_mmio + PORT_CMD);
-        readl(port_mmio + PORT_CMD); /* flush */
+        const char *emsg = NULL;
+        int rc;
 
-        /* spec says 500 msecs for each PORT_CMD_{START,FIS_RX} bit, so
-         * this is slightly incorrect.
-         */
-        msleep(500);
+        /* de-initialize port */
+        rc = ahci_deinit_port(port_mmio, hpriv->cap, &emsg);
+        if (rc)
+                ata_port_printk(ap, KERN_WARNING, "%s (%d)\n", emsg, rc);
 
         ap->private_data = NULL;
         dma_free_coherent(dev, AHCI_PORT_PRIV_DMA_SZ,
@@ -1099,7 +1216,7 @@ static int ahci_host_init(struct ata_probe_ent *probe_ent)
         struct pci_dev *pdev = to_pci_dev(probe_ent->dev);
         void __iomem *mmio = probe_ent->mmio_base;
         u32 tmp, cap_save;
-        unsigned int i, j, using_dac;
+        unsigned int i, using_dac;
         int rc;
         void __iomem *port_mmio;
 
@@ -1175,6 +1292,8 @@ static int ahci_host_init(struct ata_probe_ent *probe_ent)
         }
 
         for (i = 0; i < probe_ent->n_ports; i++) {
+                const char *emsg = NULL;
+
 #if 0 /* BIOSen initialize this incorrectly */
                 if (!(hpriv->port_map & (1 << i)))
                         continue;
@@ -1187,43 +1306,24 @@ static int ahci_host_init(struct ata_probe_ent *probe_ent)
                                 (unsigned long) mmio, i);
 
                 /* make sure port is not active */
-                tmp = readl(port_mmio + PORT_CMD);
-                VPRINTK("PORT_CMD 0x%x\n", tmp);
-                if (tmp & (PORT_CMD_LIST_ON | PORT_CMD_FIS_ON |
-                           PORT_CMD_FIS_RX | PORT_CMD_START)) {
-                        tmp &= ~(PORT_CMD_LIST_ON | PORT_CMD_FIS_ON |
-                                 PORT_CMD_FIS_RX | PORT_CMD_START);
-                        writel(tmp, port_mmio + PORT_CMD);
-                        readl(port_mmio + PORT_CMD); /* flush */
-
-                        /* spec says 500 msecs for each bit, so
-                         * this is slightly incorrect.
-                         */
-                        msleep(500);
-                }
-
-                writel(PORT_CMD_SPIN_UP, port_mmio + PORT_CMD);
-
-                j = 0;
-                while (j < 100) {
-                        msleep(10);
-                        tmp = readl(port_mmio + PORT_SCR_STAT);
-                        if ((tmp & 0xf) == 0x3)
-                                break;
-                        j++;
-                }
+                rc = ahci_deinit_port(port_mmio, hpriv->cap, &emsg);
+                if (rc)
+                        dev_printk(KERN_WARNING, &pdev->dev,
+                                   "%s (%d)\n", emsg, rc);
 
+                /* clear SError */
                 tmp = readl(port_mmio + PORT_SCR_ERR);
                 VPRINTK("PORT_SCR_ERR 0x%x\n", tmp);
                 writel(tmp, port_mmio + PORT_SCR_ERR);
 
-                /* ack any pending irq events for this port */
+                /* clear & turn off port IRQ */
                 tmp = readl(port_mmio + PORT_IRQ_STAT);
                 VPRINTK("PORT_IRQ_STAT 0x%x\n", tmp);
                 if (tmp)
                         writel(tmp, port_mmio + PORT_IRQ_STAT);
 
                 writel(1 << i, mmio + HOST_IRQ_STAT);
+                writel(0, port_mmio + PORT_IRQ_MASK);
         }
 
         tmp = readl(mmio + HOST_CTL);