Skip to content

Commit

Permalink
IB/mthca: Write FW commands through doorbell page
Browse files Browse the repository at this point in the history 
This patch is checks whether the HCA supports posting FW commands
through a doorbell page (user access region 0, or "UAR0").  If this is
supported, the driver maps UAR0 and uses it for FW commands. This can
be controlled by the value of a writable module parameter
fw_cmd_doorbell.  When the parameter is 0, the commands are posted
through HCR using the old method; otherwise if HCA is capable commands
go through UAR0.

This use of UAR0 to post commands eliminates the need for polling the
"go" bit prior to posting a new command. Since reading from a PCI
device is much more expensive then issuing a posted write, it is
expected that issuing FW commands this way will provide better CPU
utilization.

Signed-off-by: Eli Cohen <eli@mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
  • Loading branch information
Eli Cohen authored and Roland Dreier committed Mar 20, 2006
1 parent ea88fd1 commit 14abdff
Show file tree
Hide file tree
Showing 2 changed files with 136 additions and 23 deletions.
146 changes: 124 additions & 22 deletions drivers/infiniband/hw/mthca/mthca_cmd.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -182,25 +182,58 @@ struct mthca_cmd_context {
u8 status;
};

static int fw_cmd_doorbell = 1;
module_param(fw_cmd_doorbell, int, 0644);
MODULE_PARM_DESC(fw_cmd_doorbell, "post FW commands through doorbell page if nonzero "
"(and supported by FW)");

static inline int go_bit(struct mthca_dev *dev)
{
return readl(dev->hcr + HCR_STATUS_OFFSET) &
swab32(1 << HCR_GO_BIT);
}

static int mthca_cmd_post(struct mthca_dev *dev,
u64 in_param,
u64 out_param,
u32 in_modifier,
u8 op_modifier,
u16 op,
u16 token,
int event)
static void mthca_cmd_post_dbell(struct mthca_dev *dev,
u64 in_param,
u64 out_param,
u32 in_modifier,
u8 op_modifier,
u16 op,
u16 token)
{
int err = 0;
void __iomem *ptr = dev->cmd.dbell_map;
u16 *offs = dev->cmd.dbell_offsets;

mutex_lock(&dev->cmd.hcr_mutex);
__raw_writel((__force u32) cpu_to_be32(in_param >> 32), ptr + offs[0]);
wmb();
__raw_writel((__force u32) cpu_to_be32(in_param & 0xfffffffful), ptr + offs[1]);
wmb();
__raw_writel((__force u32) cpu_to_be32(in_modifier), ptr + offs[2]);
wmb();
__raw_writel((__force u32) cpu_to_be32(out_param >> 32), ptr + offs[3]);
wmb();
__raw_writel((__force u32) cpu_to_be32(out_param & 0xfffffffful), ptr + offs[4]);
wmb();
__raw_writel((__force u32) cpu_to_be32(token << 16), ptr + offs[5]);
wmb();
__raw_writel((__force u32) cpu_to_be32((1 << HCR_GO_BIT) |
(1 << HCA_E_BIT) |
(op_modifier << HCR_OPMOD_SHIFT) |
op), ptr + offs[6]);
wmb();
__raw_writel((__force u32) 0, ptr + offs[7]);
wmb();
}

static int mthca_cmd_post_hcr(struct mthca_dev *dev,
u64 in_param,
u64 out_param,
u32 in_modifier,
u8 op_modifier,
u16 op,
u16 token,
int event)
{
if (event) {
unsigned long end = jiffies + GO_BIT_TIMEOUT;

Expand All @@ -210,10 +243,8 @@ static int mthca_cmd_post(struct mthca_dev *dev,
}
}

if (go_bit(dev)) {
err = -EAGAIN;
goto out;
}
if (go_bit(dev))
return -EAGAIN;

/*
* We use writel (instead of something like memcpy_toio)
Expand All @@ -236,7 +267,29 @@ static int mthca_cmd_post(struct mthca_dev *dev,
(op_modifier << HCR_OPMOD_SHIFT) |
op), dev->hcr + 6 * 4);

out:
return 0;
}

static int mthca_cmd_post(struct mthca_dev *dev,
u64 in_param,
u64 out_param,
u32 in_modifier,
u8 op_modifier,
u16 op,
u16 token,
int event)
{
int err = 0;

mutex_lock(&dev->cmd.hcr_mutex);

if (event && dev->cmd.flags & MTHCA_CMD_POST_DOORBELLS && fw_cmd_doorbell)
mthca_cmd_post_dbell(dev, in_param, out_param, in_modifier,
op_modifier, op, token);
else
err = mthca_cmd_post_hcr(dev, in_param, out_param, in_modifier,
op_modifier, op, token, event);

mutex_unlock(&dev->cmd.hcr_mutex);
return err;
}
Expand Down Expand Up @@ -386,7 +439,7 @@ static int mthca_cmd_box(struct mthca_dev *dev,
unsigned long timeout,
u8 *status)
{
if (dev->cmd.use_events)
if (dev->cmd.flags & MTHCA_CMD_USE_EVENTS)
return mthca_cmd_wait(dev, in_param, &out_param, 0,
in_modifier, op_modifier, op,
timeout, status);
Expand Down Expand Up @@ -423,7 +476,7 @@ static int mthca_cmd_imm(struct mthca_dev *dev,
unsigned long timeout,
u8 *status)
{
if (dev->cmd.use_events)
if (dev->cmd.flags & MTHCA_CMD_USE_EVENTS)
return mthca_cmd_wait(dev, in_param, out_param, 1,
in_modifier, op_modifier, op,
timeout, status);
Expand All @@ -437,7 +490,7 @@ int mthca_cmd_init(struct mthca_dev *dev)
{
mutex_init(&dev->cmd.hcr_mutex);
sema_init(&dev->cmd.poll_sem, 1);
dev->cmd.use_events = 0;
dev->cmd.flags = 0;

dev->hcr = ioremap(pci_resource_start(dev->pdev, 0) + MTHCA_HCR_BASE,
MTHCA_HCR_SIZE);
Expand All @@ -461,6 +514,8 @@ void mthca_cmd_cleanup(struct mthca_dev *dev)
{
pci_pool_destroy(dev->cmd.pool);
iounmap(dev->hcr);
if (dev->cmd.flags & MTHCA_CMD_POST_DOORBELLS)
iounmap(dev->cmd.dbell_map);
}

/*
Expand Down Expand Up @@ -498,7 +553,8 @@ int mthca_cmd_use_events(struct mthca_dev *dev)
; /* nothing */
--dev->cmd.token_mask;

dev->cmd.use_events = 1;
dev->cmd.flags |= MTHCA_CMD_USE_EVENTS;

down(&dev->cmd.poll_sem);

return 0;
Expand All @@ -511,7 +567,7 @@ void mthca_cmd_use_polling(struct mthca_dev *dev)
{
int i;

dev->cmd.use_events = 0;
dev->cmd.flags &= ~MTHCA_CMD_USE_EVENTS;

for (i = 0; i < dev->cmd.max_cmds; ++i)
down(&dev->cmd.event_sem);
Expand Down Expand Up @@ -661,19 +717,52 @@ int mthca_RUN_FW(struct mthca_dev *dev, u8 *status)
return mthca_cmd(dev, 0, 0, 0, CMD_RUN_FW, CMD_TIME_CLASS_A, status);
}

static void mthca_setup_cmd_doorbells(struct mthca_dev *dev, u64 base)
{
unsigned long addr;
u16 max_off = 0;
int i;

for (i = 0; i < 8; ++i)
max_off = max(max_off, dev->cmd.dbell_offsets[i]);

if ((base & PAGE_MASK) != ((base + max_off) & PAGE_MASK)) {
mthca_warn(dev, "Firmware doorbell region at 0x%016llx, "
"length 0x%x crosses a page boundary\n",
(unsigned long long) base, max_off);
return;
}

addr = pci_resource_start(dev->pdev, 2) +
((pci_resource_len(dev->pdev, 2) - 1) & base);
dev->cmd.dbell_map = ioremap(addr, max_off + sizeof(u32));
if (!dev->cmd.dbell_map)
return;

dev->cmd.flags |= MTHCA_CMD_POST_DOORBELLS;
mthca_dbg(dev, "Mapped doorbell page for posting FW commands\n");
}

int mthca_QUERY_FW(struct mthca_dev *dev, u8 *status)
{
struct mthca_mailbox *mailbox;
u32 *outbox;
u64 base;
u32 tmp;
int err = 0;
u8 lg;
int i;

#define QUERY_FW_OUT_SIZE 0x100
#define QUERY_FW_VER_OFFSET 0x00
#define QUERY_FW_MAX_CMD_OFFSET 0x0f
#define QUERY_FW_ERR_START_OFFSET 0x30
#define QUERY_FW_ERR_SIZE_OFFSET 0x38

#define QUERY_FW_CMD_DB_EN_OFFSET 0x10
#define QUERY_FW_CMD_DB_OFFSET 0x50
#define QUERY_FW_CMD_DB_BASE 0x60

#define QUERY_FW_START_OFFSET 0x20
#define QUERY_FW_END_OFFSET 0x28

Expand Down Expand Up @@ -702,16 +791,29 @@ int mthca_QUERY_FW(struct mthca_dev *dev, u8 *status)
((dev->fw_ver & 0xffff0000ull) >> 16) |
((dev->fw_ver & 0x0000ffffull) << 16);

mthca_dbg(dev, "FW version %012llx, max commands %d\n",
(unsigned long long) dev->fw_ver, dev->cmd.max_cmds);

MTHCA_GET(lg, outbox, QUERY_FW_MAX_CMD_OFFSET);
dev->cmd.max_cmds = 1 << lg;
MTHCA_GET(dev->catas_err.addr, outbox, QUERY_FW_ERR_START_OFFSET);
MTHCA_GET(dev->catas_err.size, outbox, QUERY_FW_ERR_SIZE_OFFSET);

mthca_dbg(dev, "FW version %012llx, max commands %d\n",
(unsigned long long) dev->fw_ver, dev->cmd.max_cmds);
mthca_dbg(dev, "Catastrophic error buffer at 0x%llx, size 0x%x\n",
(unsigned long long) dev->catas_err.addr, dev->catas_err.size);

MTHCA_GET(tmp, outbox, QUERY_FW_CMD_DB_EN_OFFSET);
if (tmp & 0x1) {
mthca_dbg(dev, "FW supports commands through doorbells\n");

MTHCA_GET(base, outbox, QUERY_FW_CMD_DB_BASE);
for (i = 0; i < MTHCA_CMD_NUM_DBELL_DWORDS; ++i)
MTHCA_GET(dev->cmd.dbell_offsets[i], outbox,
QUERY_FW_CMD_DB_OFFSET + (i << 1));

mthca_setup_cmd_doorbells(dev, base);
}

if (mthca_is_memfree(dev)) {
MTHCA_GET(dev->fw.arbel.fw_pages, outbox, QUERY_FW_SIZE_OFFSET);
MTHCA_GET(dev->fw.arbel.clr_int_base, outbox, QUERY_FW_CLR_INT_BASE_OFFSET);
Expand Down
13 changes: 12 additions & 1 deletion drivers/infiniband/hw/mthca/mthca_dev.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -110,9 +110,17 @@ enum {
MTHCA_OPCODE_INVALID = 0xff
};

enum {
MTHCA_CMD_USE_EVENTS = 1 << 0,
MTHCA_CMD_POST_DOORBELLS = 1 << 1
};

enum {
MTHCA_CMD_NUM_DBELL_DWORDS = 8
};

struct mthca_cmd {
struct pci_pool *pool;
int use_events;
struct mutex hcr_mutex;
struct semaphore poll_sem;
struct semaphore event_sem;
Expand All @@ -121,6 +129,9 @@ struct mthca_cmd {
int free_head;
struct mthca_cmd_context *context;
u16 token_mask;
u32 flags;
void __iomem *dbell_map;
u16 dbell_offsets[MTHCA_CMD_NUM_DBELL_DWORDS];
};

struct mthca_limits {
Expand Down

0 comments on commit 14abdff

Please sign in to comment.