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nfp: add async reconfiguration mechanism 

Some callers of nfp_net_reconfig() are in atomic context so
we used to busy wait for commands to complete.  In worst case
scenario that means locking up a core for up to 5 seconds
when a command times out.  Lets add a timer-based mechanism
of asynchronously checking whether reconfiguration completed
successfully for atomic callers to use.  Non-atomic callers
can now just sleep.

The approach taken is quite simple because (1) synchronous
reconfigurations always happen under RTNL (or before device
is registered); (2) we can coalesce pending reconfigs.
There is no need for request queues, timer which eventually
takes a look at reconfiguration result to report errors is
good enough.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jakub Kicinski 2016-04-16 11:25:54 +01:00 committed by David S. Miller
parent 180012dc05
commit 3d780b926a
2 changed files with 157 additions and 27 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
drivers/net/ethernet/netronome/nfp/nfp_net.h
View File

@ -59,8 +59,8 @@
netdev_warn((nn)->netdev, fmt, ## args); \
} while (0)
/* Max time to wait for NFP to respond on updates (in ms) */
#define NFP_NET_POLL_TIMEOUT 5000
/* Max time to wait for NFP to respond on updates (in seconds) */
#define NFP_NET_POLL_TIMEOUT 5
/* Bar allocation */
#define NFP_NET_CRTL_BAR 0
@ -447,6 +447,10 @@ static inline bool nfp_net_fw_ver_eq(struct nfp_net_fw_version *fw_ver,
* @shared_name: Name for shared interrupt
* @me_freq_mhz: ME clock_freq (MHz)
* @reconfig_lock: Protects HW reconfiguration request regs/machinery
* @reconfig_posted: Pending reconfig bits coming from async sources
* @reconfig_timer_active: Timer for reading reconfiguration results is pending
* @reconfig_sync_present: Some thread is performing synchronous reconfig
* @reconfig_timer: Timer for async reading of reconfig results
* @link_up: Is the link up?
* @link_status_lock: Protects @link_up and ensures atomicity with BAR reading
* @rx_coalesce_usecs: RX interrupt moderation usecs delay parameter
@ -531,6 +535,10 @@ struct nfp_net {
spinlock_t link_status_lock;
spinlock_t reconfig_lock;
u32 reconfig_posted;
bool reconfig_timer_active;
bool reconfig_sync_present;
struct timer_list reconfig_timer;
u32 rx_coalesce_usecs;
u32 rx_coalesce_max_frames;

172
drivers/net/ethernet/netronome/nfp/nfp_net_common.c
View File

@ -80,6 +80,116 @@ void nfp_net_get_fw_version(struct nfp_net_fw_version *fw_ver,
put_unaligned_le32(reg, fw_ver);
}
/* Firmware reconfig
*
* Firmware reconfig may take a while so we have two versions of it -
* synchronous and asynchronous (posted). All synchronous callers are holding
* RTNL so we don't have to worry about serializing them.
*/
static void nfp_net_reconfig_start(struct nfp_net *nn, u32 update)
{
nn_writel(nn, NFP_NET_CFG_UPDATE, update);
/* ensure update is written before pinging HW */
nn_pci_flush(nn);
nfp_qcp_wr_ptr_add(nn->qcp_cfg, 1);
}
/* Pass 0 as update to run posted reconfigs. */
static void nfp_net_reconfig_start_async(struct nfp_net *nn, u32 update)
{
update |= nn->reconfig_posted;
nn->reconfig_posted = 0;
nfp_net_reconfig_start(nn, update);
nn->reconfig_timer_active = true;
mod_timer(&nn->reconfig_timer, jiffies + NFP_NET_POLL_TIMEOUT * HZ);
}
static bool nfp_net_reconfig_check_done(struct nfp_net *nn, bool last_check)
{
u32 reg;
reg = nn_readl(nn, NFP_NET_CFG_UPDATE);
if (reg == 0)
return true;
if (reg & NFP_NET_CFG_UPDATE_ERR) {
nn_err(nn, "Reconfig error: 0x%08x\n", reg);
return true;
} else if (last_check) {
nn_err(nn, "Reconfig timeout: 0x%08x\n", reg);
return true;
}
return false;
}
static int nfp_net_reconfig_wait(struct nfp_net *nn, unsigned long deadline)
{
bool timed_out = false;
/* Poll update field, waiting for NFP to ack the config */
while (!nfp_net_reconfig_check_done(nn, timed_out)) {
msleep(1);
timed_out = time_is_before_eq_jiffies(deadline);
}
if (nn_readl(nn, NFP_NET_CFG_UPDATE) & NFP_NET_CFG_UPDATE_ERR)
return -EIO;
return timed_out ? -EIO : 0;
}
static void nfp_net_reconfig_timer(unsigned long data)
{
struct nfp_net *nn = (void *)data;
spin_lock_bh(&nn->reconfig_lock);
nn->reconfig_timer_active = false;
/* If sync caller is present it will take over from us */
if (nn->reconfig_sync_present)
goto done;
/* Read reconfig status and report errors */
nfp_net_reconfig_check_done(nn, true);
if (nn->reconfig_posted)
nfp_net_reconfig_start_async(nn, 0);
done:
spin_unlock_bh(&nn->reconfig_lock);
}
/**
* nfp_net_reconfig_post() - Post async reconfig request
* @nn: NFP Net device to reconfigure
* @update: The value for the update field in the BAR config
*
* Record FW reconfiguration request. Reconfiguration will be kicked off
* whenever reconfiguration machinery is idle. Multiple requests can be
* merged together!
*/
static void nfp_net_reconfig_post(struct nfp_net *nn, u32 update)
{
spin_lock_bh(&nn->reconfig_lock);
/* Sync caller will kick off async reconf when it's done, just post */
if (nn->reconfig_sync_present) {
nn->reconfig_posted |= update;
goto done;
}
/* Opportunistically check if the previous command is done */
if (!nn->reconfig_timer_active ||
nfp_net_reconfig_check_done(nn, false))
nfp_net_reconfig_start_async(nn, update);
else
nn->reconfig_posted |= update;
done:
spin_unlock_bh(&nn->reconfig_lock);
}
/**
* nfp_net_reconfig() - Reconfigure the firmware
* @nn: NFP Net device to reconfigure
@ -93,35 +203,45 @@ void nfp_net_get_fw_version(struct nfp_net_fw_version *fw_ver,
*/
int nfp_net_reconfig(struct nfp_net *nn, u32 update)
{
int cnt, ret = 0;
u32 new;
bool cancelled_timer = false;
u32 pre_posted_requests;
int ret;
spin_lock_bh(&nn->reconfig_lock);
nn_writel(nn, NFP_NET_CFG_UPDATE, update);
/* ensure update is written before pinging HW */
nn_pci_flush(nn);
nfp_qcp_wr_ptr_add(nn->qcp_cfg, 1);
nn->reconfig_sync_present = true;
/* Poll update field, waiting for NFP to ack the config */
for (cnt = 0; ; cnt++) {
new = nn_readl(nn, NFP_NET_CFG_UPDATE);
if (new == 0)
break;
if (new & NFP_NET_CFG_UPDATE_ERR) {
nn_err(nn, "Reconfig error: 0x%08x\n", new);
ret = -EIO;
break;
} else if (cnt >= NFP_NET_POLL_TIMEOUT) {
nn_err(nn, "Reconfig timeout for 0x%08x after %dms\n",
update, cnt);
ret = -EIO;
break;
}
mdelay(1);
if (nn->reconfig_timer_active) {
del_timer(&nn->reconfig_timer);
nn->reconfig_timer_active = false;
cancelled_timer = true;
}
pre_posted_requests = nn->reconfig_posted;
nn->reconfig_posted = 0;
spin_unlock_bh(&nn->reconfig_lock);
if (cancelled_timer)
nfp_net_reconfig_wait(nn, nn->reconfig_timer.expires);
/* Run the posted reconfigs which were issued before we started */
if (pre_posted_requests) {
nfp_net_reconfig_start(nn, pre_posted_requests);
nfp_net_reconfig_wait(nn, jiffies + HZ * NFP_NET_POLL_TIMEOUT);
}
nfp_net_reconfig_start(nn, update);
ret = nfp_net_reconfig_wait(nn, jiffies + HZ * NFP_NET_POLL_TIMEOUT);
spin_lock_bh(&nn->reconfig_lock);
if (nn->reconfig_posted)
nfp_net_reconfig_start_async(nn, 0);
nn->reconfig_sync_present = false;
spin_unlock_bh(&nn->reconfig_lock);
return ret;
}
@ -2096,8 +2216,7 @@ static void nfp_net_set_rx_mode(struct net_device *netdev)
return;
nn_writel(nn, NFP_NET_CFG_CTRL, new_ctrl);
if (nfp_net_reconfig(nn, NFP_NET_CFG_UPDATE_GEN))
return;
nfp_net_reconfig_post(nn, NFP_NET_CFG_UPDATE_GEN);
nn->ctrl = new_ctrl;
}
@ -2405,7 +2524,7 @@ static void nfp_net_set_vxlan_port(struct nfp_net *nn, int idx, __be16 port)
be16_to_cpu(nn->vxlan_ports[i + 1]) << 16 |
be16_to_cpu(nn->vxlan_ports[i]));
nfp_net_reconfig(nn, NFP_NET_CFG_UPDATE_VXLAN);
nfp_net_reconfig_post(nn, NFP_NET_CFG_UPDATE_VXLAN);
}
/**
@ -2551,6 +2670,9 @@ struct nfp_net *nfp_net_netdev_alloc(struct pci_dev *pdev,
spin_lock_init(&nn->reconfig_lock);
spin_lock_init(&nn->link_status_lock);
setup_timer(&nn->reconfig_timer,
nfp_net_reconfig_timer, (unsigned long)nn);
return nn;
}