From d0c163ab63932a340dd20ade6984a5d6fd13d4ea Mon Sep 17 00:00:00 2001
From: Adam Wujek <adam.wujek@cern.ch>
Date: Fri, 19 Feb 2016 11:35:59 +0100
Subject: [PATCH] kernel/wr_pstats: get rid of userv
Apply zero bias at every read from FPGA.
Signed-off-by: Adam Wujek <adam.wujek@cern.ch>
---
kernel/wr_pstats/wr_pstats.c | 31 ++++++++++++++++++++++---------
1 file changed, 22 insertions(+), 9 deletions(-)
diff --git a/kernel/wr_pstats/wr_pstats.c b/kernel/wr_pstats/wr_pstats.c
index fe85890a3..5eb1dbf4e 100644
--- a/kernel/wr_pstats/wr_pstats.c
+++ b/kernel/wr_pstats/wr_pstats.c
@@ -116,7 +116,6 @@ struct cntrs_dev {
/* there is no need to keep 64bits for zero values,
* part which is read from FPGA is enough */
uint16_t zeros[PSTATS_MAX_NPORTS][PSTATS_MAX_NUM_OF_COUNTERS];
- uint64_t userv[PSTATS_MAX_NPORTS][PSTATS_MAX_NUM_OF_COUNTERS];
struct PSTATS_WB __iomem *regs;
/* prevents from simultaneous access to cntrs array from tasklet and
@@ -286,6 +285,10 @@ static int rd_cnt_word(int port, int adr)
ptr = &(pstats_dev.cntrs[port][4 * adr + i]);
*ptr &= PSTATS_MSB_MSK;
*ptr |= hwcnt_to_sw(val[0], val[1], i);
+ /* apply zero bias,
+ * NOTE: since cntrs are monotonic, they're always bigger than
+ * zeros */
+ *ptr -= pstats_dev.zeros[port][4 * adr + i];
spin_unlock(&pstats_dev.port_mutex[port]);
}
@@ -308,11 +311,16 @@ static void pstats_zero(int port)
pstats_rd_cntrs(port);
spin_lock(&pstats_dev.port_mutex[port]);
for (i = 0; i < PSTATS_MAX_NUM_OF_COUNTERS; i++) {
+ /* since cntrs is monotonic it will never happen that zero will
+ * be bigger than cntrs */
+ /* add zeros since it was substracted before in
+ * pstats_rd_cntrs (rd_cnt_word) */
+ pstats_dev.cntrs[port][i] += pstats_dev.zeros[port][i];
+ /* clear 48 MSBits */
+ pstats_dev.cntrs[port][i] &= PSTATS_LSB_MSK;
/* Copy 16 LSBits to zero */
pstats_dev.zeros[port][i] =
(uint16_t) pstats_dev.cntrs[port][i];
- /* clear 48 MSBits */
- pstats_dev.cntrs[port][i] &= PSTATS_LSB_MSK;
}
spin_unlock(&pstats_dev.port_mutex[port]);
}
@@ -340,8 +348,8 @@ static int pstats_desc_handler(ctl_table *ctl, int write, void *buffer,
static int pstats_handler(ctl_table *ctl, int write, void *buffer,
size_t *lenp, loff_t *ppos)
{
- int i, port;
- struct cntrs_dev *d = &pstats_dev;
+ int port;
+ int ret;
port = (int)ctl->extra1;
@@ -357,18 +365,23 @@ static int pstats_handler(ctl_table *ctl, int write, void *buffer,
}
if (port < pstats_nports) {
+ /* read counters including correction of zeros offset */
pstats_rd_cntrs(port);
- for (i = 0; i < firmware_counters; i++)
- d->userv[port][i] = d->cntrs[port][i] - d->zeros[port][i];
} else {
/* stuff for info file, read at module load time */
pstats_info[PINFO_VER] = firmware_version;
pstats_info[PINFO_CNTPW] = firmware_cpw;
pstats_info[PINFO_CNTPP] = firmware_counters;
}
+ /* It might happen that irq comes between reading MSB 32 bits and
+ * LSB 32 bits of particualr counter.
+ * In that case counter's value would be lower than previous one */
+ spin_lock(&pstats_dev.port_mutex[port]);
/* each value will be split into two unsigned longs,
* each counter has to be assembled in software reading pstats */
- return proc_dointvec(ctl, 0, buffer, lenp, ppos);
+ ret = proc_dointvec(ctl, 0, buffer, lenp, ppos);
+ spin_unlock(&pstats_dev.port_mutex[port]);
+ return ret;
}
/* one per port, then info and description, and terminator, filled at init time */
@@ -470,7 +483,7 @@ static int __init pstats_init(void)
for (i = 0; i < pstats_nports; ++i) {
pstats_ctl_table[i].procname = portnames[i];
- pstats_ctl_table[i].data = &pstats_dev.userv[i];
+ pstats_ctl_table[i].data = &pstats_dev.cntrs[i];
/* each value will be split into two unsigned longs,
* each counter has to be assembled in software reading pstats
*/
--
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