Fwd: cciss: PCI power management reset for kexec

From: mikem1355
Date: Mon Feb 09 2009 - 11:20:54 EST

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---------- Forwarded message ----------
From: Mike Miller <mike.mil...@xxxxxx>
Date: Feb 7, 1:40 pm
Subject: cciss: PCI power management reset for kexec
To: linux.kernel

Patch 1 of 1

This patch provides the better "kick-in-the-pants" on driver load in a
kexec'ed environment.

I've successfully sanity tested the port in my lab. Randy, please
apply and
test. You seem to be able to bring out the worst in the driver. ;-)

Author: Chip Coldwell <coldw...@xxxxxxxxxx>

CCISS: Use PCI power management to reset the controller

The kexec kernel resets theCCISShardware 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 theCCISS"No-op" message to determine when the
controller firmware has recovered from the PCI PM reset.

Signed-off-by: Mike Miller <mike.mil...@xxxxxx>

I should have given more detail about using this reset patch. You must
use the kernel command line option "reset_devices" in the kexec
command line. My testing used:

# kexec -l /boot/vmlinuz --initrd=/boot/initrd.img --append="root=/dev/
cciss/c0d0p2 reset_devices 3 maxcpus=1 irqpoll"

then

# kexec -e

Please consider this for inclusion.

-------------------------------------------------------------------------------
diff --git a/drivers/block/cciss.c b/drivers/block/cciss.c
index 01e6938..ff4a105 100644
--- a/drivers/block/cciss.c
+++ b/drivers/block/cciss.c
@@ -3390,6 +3390,205 @@ 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
+ CCISScommands, 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 theCCISSdocument (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);
+
+ set_current_state(TASK_UNINTERRUPTIBLE);
+ schedule_timeout(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);
+
+ set_current_state(TASK_UNINTERRUPTIBLE);
+ schedule_timeout(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 +3603,24 @@ 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;
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Next message: Dean Nelson: "[PATCH] SGI IA64 UV: fix ia64 build error in the linux-next tree"
Previous message: Greg KH: "Re: [stable] scheduler nice 19 versus 'idle' behavior / staticlow-priority scheduling"
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