From: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
To: Krishna Chaitanya Chundru <quic_krichai@quicinc.com>
Cc: "Bjorn Helgaas" <bhelgaas@google.com>,
linux-pci@vger.kernel.org, linux-arm-msm@vger.kernel.org,
linux-kernel@vger.kernel.org, quic_vbadigan@quicinc.com,
quic_hemantk@quicinc.com, quic_nitegupt@quicinc.com,
quic_skananth@quicinc.com, quic_ramkri@quicinc.com,
swboyd@chromium.org,
"Prasad Malisetty" <quic_pmaliset@quicinc.com>,
"Saheed O. Bolarinwa" <refactormyself@gmail.com>,
"Rajat Jain" <rajatja@google.com>,
"Krzysztof Wilczyński" <kw@linux.com>,
helgaas@kernel.org
Subject: Re: [PATCH v5] PCI/ASPM: Update LTR threshold based upon reported max latencies
Date: Fri, 15 Jul 2022 13:58:52 +0530 [thread overview]
Message-ID: <20220715082852.GC12197@workstation> (raw)
In-Reply-To: <20f88022-e9b1-53b3-8832-85edc713ef6a@quicinc.com>
On Wed, Jun 15, 2022 at 06:53:18PM +0530, Krishna Chaitanya Chundru wrote:
> A Gentle remainder please review it.
>
> On 6/10/2022 10:38 AM, Krishna chaitanya chundru wrote:
> > From: Prasad Malisetty <quic_pmaliset@quicinc.com>
> >
> > In ASPM driver, LTR threshold scale and value are updated based on
> > tcommon_mode and t_poweron values. In kioxia NVMe L1.2 is failing due to
> > LTR threshold scale and value are greater values than max snoop/non-snoop
> > value.
> >
> > Based on PCIe r4.1, sec 5.5.1, L1.2 substate must be entered when
> > reported snoop/no-snoop values is greather than or equal to
> > LTR_L1.2_THRESHOLD value.
> >
> > Signed-off-by: Prasad Malisetty <quic_pmaliset@quicinc.com>
> > Signed-off-by: Krishna chaitanya chundru <quic_krichai@quicinc.com>
As Stephen noted in previous verison, you should sent the newer versions
separately and not as a reply to previous ones. So please sent v6 with
my tag as well.
Thanks,
Mani
> > ---
> >
> > I am taking this patch forward as prasad is no more working with our org.
> > Changes since v4:
> > - Replaced conditional statements with min and max.
> > changes since v3:
> > - Changed the logic to include this condition "snoop/nosnoop
> > latencies are not equal to zero and lower than LTR_L1.2_THRESHOLD"
> > Changes since v2:
> > - Replaced LTRME logic with max snoop/no-snoop latencies check.
> > Changes since v1:
> > - Added missing variable declaration in v1 patch
> > ---
> > drivers/pci/pcie/aspm.c | 30 ++++++++++++++++++++++++++++++
> > 1 file changed, 30 insertions(+)
> >
> > diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
> > index a96b742..676c03e 100644
> > --- a/drivers/pci/pcie/aspm.c
> > +++ b/drivers/pci/pcie/aspm.c
> > @@ -461,14 +461,36 @@ static void aspm_calc_l1ss_info(struct pcie_link_state *link,
> > {
> > struct pci_dev *child = link->downstream, *parent = link->pdev;
> > u32 val1, val2, scale1, scale2;
> > + u32 max_val, max_scale, max_snp_scale, max_snp_val, max_nsnp_scale, max_nsnp_val;
> > u32 t_common_mode, t_power_on, l1_2_threshold, scale, value;
> > u32 ctl1 = 0, ctl2 = 0;
> > u32 pctl1, pctl2, cctl1, cctl2;
> > u32 pl1_2_enables, cl1_2_enables;
> > + u16 ltr;
> > + u16 max_snoop_lat, max_nosnoop_lat;
> > if (!(link->aspm_support & ASPM_STATE_L1_2_MASK))
> > return;
> > + ltr = pci_find_ext_capability(child, PCI_EXT_CAP_ID_LTR);
> > + if (!ltr)
> > + return;
> > +
> > + pci_read_config_word(child, ltr + PCI_LTR_MAX_SNOOP_LAT, &max_snoop_lat);
> > + pci_read_config_word(child, ltr + PCI_LTR_MAX_NOSNOOP_LAT, &max_nosnoop_lat);
> > +
> > + max_snp_scale = (max_snoop_lat & PCI_LTR_SCALE_MASK) >> PCI_LTR_SCALE_SHIFT;
> > + max_snp_val = max_snoop_lat & PCI_LTR_VALUE_MASK;
> > +
> > + max_nsnp_scale = (max_nosnoop_lat & PCI_LTR_SCALE_MASK) >> PCI_LTR_SCALE_SHIFT;
> > + max_nsnp_val = max_nosnoop_lat & PCI_LTR_VALUE_MASK;
> > +
> > + /* choose the greater max scale value between snoop and no snoop value*/
> > + max_scale = max(max_snp_scale, max_nsnp_scale);
> > +
> > + /* choose the greater max value between snoop and no snoop scales */
> > + max_val = max(max_snp_val, max_nsnp_val);
> > +
> > /* Choose the greater of the two Port Common_Mode_Restore_Times */
> > val1 = (parent_l1ss_cap & PCI_L1SS_CAP_CM_RESTORE_TIME) >> 8;
> > val2 = (child_l1ss_cap & PCI_L1SS_CAP_CM_RESTORE_TIME) >> 8;
> > @@ -501,6 +523,14 @@ static void aspm_calc_l1ss_info(struct pcie_link_state *link,
> > */
> > l1_2_threshold = 2 + 4 + t_common_mode + t_power_on;
> > encode_l12_threshold(l1_2_threshold, &scale, &value);
> > +
> > + /*
> > + * Based on PCIe r4.1, sec 5.5.1, L1.2 substate must be entered when reported
> > + * snoop/no-snoop values are greather than or equal to LTR_L1.2_THRESHOLD value.
> > + */
> > + scale = min(scale, max_scale);
> > + value = min(value, max_val);
> > +
> > ctl1 |= t_common_mode << 8 | scale << 29 | value << 16;
> > /* Some broken devices only support dword access to L1 SS */
next prev parent reply other threads:[~2022-07-15 8:29 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-07 18:59 [PATCH v2] [RFC PATCH] PCI: Update LTR threshold based on LTRME bit Prasad Malisetty
2022-03-17 19:07 ` Stephen Boyd
2022-04-05 6:24 ` Prasad Malisetty (Temp)
2022-04-05 18:57 ` Stephen Boyd
2022-04-05 16:08 ` Bjorn Helgaas
2022-04-12 22:46 ` Bjorn Helgaas
2022-06-01 12:23 ` [PATCH v3] PCI/ASPM: Update LTR threshold based upon reported max latencies Krishna chaitanya chundru
2022-06-01 12:27 ` Krishna Chaitanya Chundru
2022-06-02 8:29 ` Manivannan Sadhasivam
2022-06-02 9:59 ` Krishna Chaitanya Chundru
2022-06-03 7:54 ` [PATCH v4] " Krishna chaitanya chundru
2022-06-08 22:22 ` Stephen Boyd
2022-06-10 5:08 ` [PATCH v5] " Krishna chaitanya chundru
2022-06-15 13:23 ` Krishna Chaitanya Chundru
2022-07-15 8:28 ` Manivannan Sadhasivam [this message]
2022-07-15 11:28 ` Krishna Chaitanya Chundru
2022-06-15 17:39 ` Manivannan Sadhasivam
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