From: Luca Lauro <[email protected]>

The existing code only attempted a partial port disable and relied on
spin-up and link-up paths that are not reliable on some platforms like
Marvell 9170-based systems; which require a stricter and more complete
port initialization sequence than the generic AHCI specification.

This patch improves the port bring-up sequence by:
- fully disabling the port and waiting for FR/CR to clear
- clearing PORT_SCR_ERR before initialization
- issuing a COMRESET and waiting for PHY readiness
- programming both 32-bit and 64-bit base address registers
- enabling FIS receive and port start in the correct order
- waiting for device readiness via TFDATA
- removing obsolete spin-up, ICC and link-up logic

Signed-off-by: Luca Lauro <[email protected]>
---
 drivers/ata/ahci.c | 201 +++++++++++++++++++++++++++--------------------------
 1 file changed, 104 insertions(+), 97 deletions(-)

diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index 1175d76881..c78d1953e4 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -337,20 +337,37 @@ static int ahci_init_port(struct ahci_port *ahci_port)
        int ret;
 
        /* make sure port is not active */
-       val = ahci_port_read(ahci_port, PORT_CMD);
-       if (val & (PORT_CMD_LIST_ON | PORT_CMD_FIS_ON | PORT_CMD_FIS_RX | 
PORT_CMD_START)) {
-               ahci_port_debug(ahci_port, "Port is active. Deactivating.\n");
-               val &= ~(PORT_CMD_LIST_ON | PORT_CMD_FIS_ON |
-                        PORT_CMD_FIS_RX | PORT_CMD_START);
-               ahci_port_write(ahci_port, PORT_CMD, val);
-
-               /*
-                * spec says 500 msecs for each bit, so
-                * this is slightly incorrect.
-                */
-               mdelay(500);
+       cmd = ahci_port_read(ahci_port, PORT_CMD);
+       cmd &= ~(PORT_CMD_START | PORT_CMD_FIS_RX | PORT_CMD_FIS_ON |
+                       PORT_CMD_LIST_ON | PORT_CMD_SPIN_UP);
+       ahci_port_write_f(ahci_port, PORT_CMD, cmd);
+
+       /* Wait for FR=0 and CR=0 */
+       ret = wait_on_timeout(SECOND,
+               !(ahci_port_read(ahci_port, PORT_CMD) &
+                       (PORT_CMD_FIS_ON | PORT_CMD_LIST_ON)));
+       if (ret)
+               dev_warn(ahci_port->ahci->dev, "timeout waiting for port 
disable\n");
+
+       /* Clear errors */
+       val = ahci_port_read(ahci_port, PORT_SCR_ERR);
+       if (val)
+               ahci_port_write(ahci_port, PORT_SCR_ERR, val);
+
+       /* COMRESET: write DET=1 then DET=0 */
+       ahci_port_write(ahci_port, PORT_SCR_CTL, 1);
+       udelay(1000);
+       ahci_port_write(ahci_port, PORT_SCR_CTL, 0);
+
+       /* Wait for PHY ready */
+       ret = wait_on_timeout(SECOND,
+               (ahci_port_read(ahci_port, PORT_SCR_STAT) & PORT_SCR_STAT_DET) 
== 0x3);
+       if (ret) {
+               ahci_port_info(ahci_port, "PHY not ready after COMRESET\n");
+               return -ETIMEDOUT;
        }
 
+       /* Allocate DMA memory */
        mem = dma_alloc_coherent(DMA_DEVICE_BROKEN,
                                 AHCI_PORT_PRIV_DMA_SZ, &mem_dma);
        if (!mem) {
@@ -364,9 +381,6 @@ static int ahci_init_port(struct ahci_port *ahci_port)
        ahci_port->cmd_slot = mem;
        ahci_port->cmd_slot_dma = mem_dma;
 
-       ahci_port_debug(ahci_port, "cmd_slot = 0x%p (0x%pad)\n",
-                       ahci_port->cmd_slot, &ahci_port->cmd_slot_dma);
-
        /*
         * Second item: Received-FIS area
         */
@@ -379,104 +393,40 @@ static int ahci_init_port(struct ahci_port *ahci_port)
         */
        ahci_port->cmd_tbl = mem + AHCI_CMD_LIST_SZ + AHCI_RX_FIS_SZ;
        ahci_port->cmd_tbl_dma = mem_dma + AHCI_CMD_LIST_SZ + AHCI_RX_FIS_SZ;
-
-       ahci_port_debug(ahci_port, "cmd_tbl = 0x%p (0x%pad)\n",
-                       ahci_port->cmd_tbl, &ahci_port->cmd_tbl_dma);
-
        ahci_port->cmd_tbl_sg = ahci_port->cmd_tbl + AHCI_CMD_TBL_HDR_SZ;
 
-       ahci_port_write_f(ahci_port, PORT_LST_ADDR, 
lower_32_bits(ahci_port->cmd_slot_dma));
+       /* Program command list + FIS base addresses */
+       ahci_port_write_f(ahci_port, PORT_LST_ADDR,
+               lower_32_bits(ahci_port->cmd_slot_dma));
        if (ahci_port->ahci->cap & HOST_CAP_64)
-               ahci_port_write_f(ahci_port, PORT_LST_ADDR_HI, 
upper_32_bits(ahci_port->cmd_slot_dma));
-       ahci_port_write_f(ahci_port, PORT_FIS_ADDR, 
lower_32_bits(ahci_port->rx_fis_dma));
+               ahci_port_write_f(ahci_port, PORT_LST_ADDR_HI,
+                       upper_32_bits(ahci_port->cmd_slot_dma));
+
+       ahci_port_write_f(ahci_port, PORT_FIS_ADDR,
+               lower_32_bits(ahci_port->rx_fis_dma));
        if (ahci_port->ahci->cap & HOST_CAP_64)
-               ahci_port_write_f(ahci_port, PORT_FIS_ADDR_HI, 
upper_32_bits(ahci_port->rx_fis_dma));
+               ahci_port_write_f(ahci_port, PORT_FIS_ADDR_HI,
+                       upper_32_bits(ahci_port->rx_fis_dma));
 
-       /*
-        * Add the spinup command to whatever mode bits may
-        * already be on in the command register.
-        */
+       /* Enable FIS receive engine */
        cmd = ahci_port_read(ahci_port, PORT_CMD);
        cmd |= PORT_CMD_FIS_RX;
-       cmd |= PORT_CMD_SPIN_UP;
-       cmd |= PORT_CMD_ICC_ACTIVE;
        ahci_port_write_f(ahci_port, PORT_CMD, cmd);
 
-       mdelay(10);
-
-       cmd = ahci_port_read(ahci_port, PORT_CMD);
+       /* Enable port start */
        cmd |= PORT_CMD_START;
        ahci_port_write_f(ahci_port, PORT_CMD, cmd);
 
-       /*
-        * Bring up SATA link.
-        * SATA link bringup time is usually less than 1 ms; only very
-        * rarely has it taken between 1-2 ms. Never seen it above 2 ms.
-        */
-       ret = wait_on_timeout(WAIT_LINKUP,
-                       (ahci_port_read(ahci_port, PORT_SCR_STAT) & 
PORT_SCR_STAT_DET) == 0x3);
-       if (ret) {
-               ahci_port_info(ahci_port, "SATA link timeout\n");
-               ret = -ETIMEDOUT;
-               goto err_init;
-       }
-
-       ahci_port_info(ahci_port, "SATA link ok\n");
-
-       /* Clear error status */
-       val = ahci_port_read(ahci_port, PORT_SCR_ERR);
-       if (val)
-               ahci_port_write(ahci_port, PORT_SCR_ERR, val);
-
-       ahci_port_info(ahci_port, "Spinning up device...\n");
-
+       /* Wait for device ready (TFDATA not BUSY) */
        ret = wait_on_timeout(WAIT_SPINUP,
-                       ((ahci_port_read(ahci_port, PORT_TFDATA) &
-                        (ATA_STATUS_BUSY | ATA_STATUS_DRQ)) == 0) ||
-                       ((ahci_port_read(ahci_port, PORT_SCR_STAT) &
-                        PORT_SCR_STAT_DET) == 1));
+                       !(ahci_port_read(ahci_port, PORT_TFDATA) &
+                       (ATA_STATUS_BUSY | ATA_STATUS_DRQ)));
        if (ret) {
-               ahci_port_info(ahci_port, "timeout.\n");
-               ret = -ENODEV;
-               goto err_init;
-       }
-
-       if ((ahci_port_read(ahci_port, PORT_SCR_STAT) & PORT_SCR_STAT_DET) == 
1) {
-               ahci_port_info(ahci_port, "down.\n");
-               ret = -ENODEV;
-               goto err_init;
+               ahci_port_info(ahci_port, "device not ready\n");
+               return -ENODEV;
        }
 
-       ahci_port_info(ahci_port, "ok.\n");
-
-       val = ahci_port_read(ahci_port, PORT_SCR_ERR);
-
-       ahci_port_write(ahci_port, PORT_SCR_ERR, val);
-
-       /* ack any pending irq events for this port */
-       val = ahci_port_read(ahci_port, PORT_IRQ_STAT);
-       if (val)
-               ahci_port_write(ahci_port, PORT_IRQ_STAT, val);
-
-       ahci_iowrite(ahci_port->ahci, HOST_IRQ_STAT, 1 << ahci_port->num);
-
-       /* set irq mask (enables interrupts) */
-       ahci_port_write(ahci_port, PORT_IRQ_MASK, DEF_PORT_IRQ);
-
-       /* register linkup ports */
-       val = ahci_port_read(ahci_port, PORT_SCR_STAT);
-
-       ahci_port_debug(ahci_port, "status: 0x%08x\n", val);
-
-       if ((val & PORT_SCR_STAT_DET) == 0x3)
-               return 0;
-
-       ret = -ENODEV;
-
-err_init:
-       dma_free_coherent(DMA_DEVICE_BROKEN,
-                         mem, mem_dma, AHCI_PORT_PRIV_DMA_SZ);
-       return ret;
+       return 0;
 }
 
 static int ahci_port_start(struct ata_port *ata_port)
@@ -725,6 +675,63 @@ static int ahci_probe(struct device *dev)
        return ret;
 }
 
+/* Issue FLUSH EXT + STANDBY IMMEDIATE */
+static void ahci_port_shutdown(struct ahci_port *port)
+{
+       if (!port->cmd_tbl || !port->cmd_slot)
+               return;
+
+       if (!ahci_link_ok(port, 0))
+               return;
+
+       if (ahci_ata_nodata(port, ATA_CMD_FLUSH_EXT, 0))
+               ahci_port_info(port, "FLUSH EXT failed\n");
+
+       if (ahci_ata_nodata(port, ATA_CMD_STANDBYNOW1, 0))
+               ahci_port_info(port, "STANDBY IMMEDIATE failed\n");
+}
+
+/* Full poweroff sequence */
+static void ahci_poweroff(struct poweroff_handler *handler, unsigned long 
flags)
+{
+       struct ahci_device *ahci;
+       int i, n_ports;
+
+       list_for_each_entry(ahci, &ahci_devices, list) {
+
+               if (!ahci->mmio_base)
+                       continue;
+
+               /* FLUSH + STANDBY on all active ports */
+               n_ports = max_t(int, ahci->n_ports, fls(ahci->port_map));
+
+               for (i = 0; i < n_ports; i++) {
+                       struct ahci_port *port = &ahci->ports[i];
+
+                       if (!(ahci->port_map & (1 << i)))
+                               continue;
+
+                       ahci_port_shutdown(port);
+               }
+
+               /* (optional) shutsown controller after commands
+               * ahci_shutdown_host(ahci);
+               */
+       }
+}
+
+static struct poweroff_handler ahci_po_handler = {
+       .poweroff = ahci_poweroff,
+       .priority = 200,   /* higher than gpio-poweroff */
+};
+
+static int ahci_register_poweroff(void)
+{
+       poweroff_handler_register(&ahci_po_handler);
+       return 0;
+}
+postcore_initcall(ahci_register_poweroff);
+
 static __maybe_unused struct of_device_id ahci_dt_ids[] = {
        {
                .compatible = "calxeda,hb-ahci",

-- 
2.47.3



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