cciss: PCI power management reset for kexec

The kexec kernel resets the CCISS hardware in three steps:

1. Use PCI power management states to reset the controller in the
   kexec kernel.

2. Clear the MSI/MSI-X bits in PCI configuration space so that MSI
   initialization in the kexec kernel doesn't fail.

3. Use the CCISS "No-op" message to determine when the controller
   firmware has recovered from the PCI PM reset.

[akpm@linux-foundation.org: cleanups]
Signed-off-by: Mike Miller <mike.miller@hp.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 215 insertions, 0 deletions

diff --git a/drivers/block/cciss.c b/drivers/block/cciss.c
index 01e69383d9c0..d2cb67b61176 100644
--- a/drivers/block/cciss.c
+++ b/drivers/block/cciss.c
@@ -3390,6 +3390,203 @@ static void free_hba(int i)
         kfree(p);
 }
 
+/* Send a message CDB to the firmware. */
+static __devinit int cciss_message(struct pci_dev *pdev, unsigned char opcode, unsigned char type)
+{
+        typedef struct {
+                CommandListHeader_struct CommandHeader;
+                RequestBlock_struct Request;
+                ErrDescriptor_struct ErrorDescriptor;
+        } Command;
+        static const size_t cmd_sz = sizeof(Command) + sizeof(ErrorInfo_struct);
+        Command *cmd;
+        dma_addr_t paddr64;
+        uint32_t paddr32, tag;
+        void __iomem *vaddr;
+        int i, err;
+
+        vaddr = ioremap_nocache(pci_resource_start(pdev, 0), pci_resource_len(pdev, 0));
+        if (vaddr == NULL)
+                return -ENOMEM;
+
+        /* The Inbound Post Queue only accepts 32-bit physical addresses for the
+           CCISS commands, so they must be allocated from the lower 4GiB of
+           memory. */
+        err = pci_set_consistent_dma_mask(pdev, DMA_32BIT_MASK);
+        if (err) {
+                iounmap(vaddr);
+                return -ENOMEM;
+        }
+
+        cmd = pci_alloc_consistent(pdev, cmd_sz, &paddr64);
+        if (cmd == NULL) {
+                iounmap(vaddr);
+                return -ENOMEM;
+        }
+
+        /* This must fit, because of the 32-bit consistent DMA mask.  Also,
+           although there's no guarantee, we assume that the address is at
+           least 4-byte aligned (most likely, it's page-aligned). */
+        paddr32 = paddr64;
+
+        cmd->CommandHeader.ReplyQueue = 0;
+        cmd->CommandHeader.SGList = 0;
+        cmd->CommandHeader.SGTotal = 0;
+        cmd->CommandHeader.Tag.lower = paddr32;
+        cmd->CommandHeader.Tag.upper = 0;
+        memset(&cmd->CommandHeader.LUN.LunAddrBytes, 0, 8);
+
+        cmd->Request.CDBLen = 16;
+        cmd->Request.Type.Type = TYPE_MSG;
+        cmd->Request.Type.Attribute = ATTR_HEADOFQUEUE;
+        cmd->Request.Type.Direction = XFER_NONE;
+        cmd->Request.Timeout = 0; /* Don't time out */
+        cmd->Request.CDB[0] = opcode;
+        cmd->Request.CDB[1] = type;
+        memset(&cmd->Request.CDB[2], 0, 14); /* the rest of the CDB is reserved */
+
+        cmd->ErrorDescriptor.Addr.lower = paddr32 + sizeof(Command);
+        cmd->ErrorDescriptor.Addr.upper = 0;
+        cmd->ErrorDescriptor.Len = sizeof(ErrorInfo_struct);
+
+        writel(paddr32, vaddr + SA5_REQUEST_PORT_OFFSET);
+
+        for (i = 0; i < 10; i++) {
+                tag = readl(vaddr + SA5_REPLY_PORT_OFFSET);
+                if ((tag & ~3) == paddr32)
+                        break;
+                schedule_timeout_uninterruptible(HZ);
+        }
+
+        iounmap(vaddr);
+
+        /* we leak the DMA buffer here ... no choice since the controller could
+           still complete the command. */
+        if (i == 10) {
+                printk(KERN_ERR "cciss: controller message %02x:%02x timed out\n",
+                        opcode, type);
+                return -ETIMEDOUT;
+        }
+
+        pci_free_consistent(pdev, cmd_sz, cmd, paddr64);
+
+        if (tag & 2) {
+                printk(KERN_ERR "cciss: controller message %02x:%02x failed\n",
+                        opcode, type);
+                return -EIO;
+        }
+
+        printk(KERN_INFO "cciss: controller message %02x:%02x succeeded\n",
+                opcode, type);
+        return 0;
+}
+
+#define cciss_soft_reset_controller(p) cciss_message(p, 1, 0)
+#define cciss_noop(p) cciss_message(p, 3, 0)
+
+static __devinit int cciss_reset_msi(struct pci_dev *pdev)
+{
+/* the #defines are stolen from drivers/pci/msi.h. */
+#define msi_control_reg(base)           (base + PCI_MSI_FLAGS)
+#define PCI_MSIX_FLAGS_ENABLE           (1 << 15)
+
+        int pos;
+        u16 control = 0;
+
+        pos = pci_find_capability(pdev, PCI_CAP_ID_MSI);
+        if (pos) {
+                pci_read_config_word(pdev, msi_control_reg(pos), &control);
+                if (control & PCI_MSI_FLAGS_ENABLE) {
+                        printk(KERN_INFO "cciss: resetting MSI\n");
+                        pci_write_config_word(pdev, msi_control_reg(pos), control & ~PCI_MSI_FLAGS_ENABLE);
+                }
+        }
+
+        pos = pci_find_capability(pdev, PCI_CAP_ID_MSIX);
+        if (pos) {
+                pci_read_config_word(pdev, msi_control_reg(pos), &control);
+                if (control & PCI_MSIX_FLAGS_ENABLE) {
+                        printk(KERN_INFO "cciss: resetting MSI-X\n");
+                        pci_write_config_word(pdev, msi_control_reg(pos), control & ~PCI_MSIX_FLAGS_ENABLE);
+                }
+        }
+
+        return 0;
+}
+
+/* This does a hard reset of the controller using PCI power management
+ * states. */
+static __devinit int cciss_hard_reset_controller(struct pci_dev *pdev)
+{
+        u16 pmcsr, saved_config_space[32];
+        int i, pos;
+
+        printk(KERN_INFO "cciss: using PCI PM to reset controller\n");
+
+        /* This is very nearly the same thing as
+
+           pci_save_state(pci_dev);
+           pci_set_power_state(pci_dev, PCI_D3hot);
+           pci_set_power_state(pci_dev, PCI_D0);
+           pci_restore_state(pci_dev);
+
+           but we can't use these nice canned kernel routines on
+           kexec, because they also check the MSI/MSI-X state in PCI
+           configuration space and do the wrong thing when it is
+           set/cleared.  Also, the pci_save/restore_state functions
+           violate the ordering requirements for restoring the
+           configuration space from the CCISS document (see the
+           comment below).  So we roll our own .... */
+
+        for (i = 0; i < 32; i++)
+                pci_read_config_word(pdev, 2*i, &saved_config_space[i]);
+
+        pos = pci_find_capability(pdev, PCI_CAP_ID_PM);
+        if (pos == 0) {
+                printk(KERN_ERR "cciss_reset_controller: PCI PM not supported\n");
+                return -ENODEV;
+        }
+
+        /* Quoting from the Open CISS Specification: "The Power
+         * Management Control/Status Register (CSR) controls the power
+         * state of the device.  The normal operating state is D0,
+         * CSR=00h.  The software off state is D3, CSR=03h.  To reset
+         * the controller, place the interface device in D3 then to
+         * D0, this causes a secondary PCI reset which will reset the
+         * controller." */
+
+        /* enter the D3hot power management state */
+        pci_read_config_word(pdev, pos + PCI_PM_CTRL, &pmcsr);
+        pmcsr &= ~PCI_PM_CTRL_STATE_MASK;
+        pmcsr |= PCI_D3hot;
+        pci_write_config_word(pdev, pos + PCI_PM_CTRL, pmcsr);
+
+        schedule_timeout_uninterruptible(HZ >> 1);
+
+        /* enter the D0 power management state */
+        pmcsr &= ~PCI_PM_CTRL_STATE_MASK;
+        pmcsr |= PCI_D0;
+        pci_write_config_word(pdev, pos + PCI_PM_CTRL, pmcsr);
+
+        schedule_timeout_uninterruptible(HZ >> 1);
+
+        /* Restore the PCI configuration space.  The Open CISS
+         * Specification says, "Restore the PCI Configuration
+         * Registers, offsets 00h through 60h. It is important to
+         * restore the command register, 16-bits at offset 04h,
+         * last. Do not restore the configuration status register,
+         * 16-bits at offset 06h."  Note that the offset is 2*i. */
+        for (i = 0; i < 32; i++) {
+                if (i == 2 || i == 3)
+                        continue;
+                pci_write_config_word(pdev, 2*i, saved_config_space[i]);
+        }
+        wmb();
+        pci_write_config_word(pdev, 4, saved_config_space[2]);
+
+        return 0;
+}
+
 /*
  *  This is it.  Find all the controllers and register them.  I really hate
  *  stealing all these major device numbers.
@@ -3404,6 +3601,24 @@ static int __devinit cciss_init_one(struct pci_dev *pdev,
         int dac, return_code;
         InquiryData_struct *inq_buff = NULL;
 
+        if (reset_devices) {
+                /* Reset the controller with a PCI power-cycle */
+                if (cciss_hard_reset_controller(pdev) || cciss_reset_msi(pdev))
+                        return -ENODEV;
+
+                /* Some devices (notably the HP Smart Array 5i Controller)
+                   need a little pause here */
+                schedule_timeout_uninterruptible(30*HZ);
+
+                /* Now try to get the controller to respond to a no-op */
+                for (i=0; i<12; i++) {
+                        if (cciss_noop(pdev) == 0)
+                                break;
+                        else
+                                printk("cciss: no-op failed%s\n", (i < 11 ? "; re-trying" : ""));
+                }
+        }
+
         i = alloc_cciss_hba();
         if (i < 0)
                 return -1;