From: Bjorn Helgaas <helgaas@kernel.org>
To: Murali Karicheri <m-karicheri2@ti.com>
Cc: linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Subject: ks_dw_pcie_initiate_link_train() question
Date: Tue, 4 Oct 2016 12:40:51 -0500 [thread overview]
Message-ID: <20161004174051.GE3449@localhost> (raw)
Hi Murali,
This code looks suspicious. Can you comment?
void ks_dw_pcie_initiate_link_train(struct keystone_pcie *ks_pcie)
{
u32 val;
/* Disable Link training */
val = readl(ks_pcie->va_app_base + CMD_STATUS);
val &= ~LTSSM_EN_VAL;
writel(LTSSM_EN_VAL | val, ks_pcie->va_app_base + CMD_STATUS);
Here we cleared the LTSSM_EN_VAL bit in "val", but then we add it
right back in before writing it back to CMD_STATUS.
That looks like a cut and paste error to me, but of course I don't
know the hardware.
/* Initiate Link Training */
val = readl(ks_pcie->va_app_base + CMD_STATUS);
writel(LTSSM_EN_VAL | val, ks_pcie->va_app_base + CMD_STATUS);
}
WARNING: multiple messages have this Message-ID (diff)
From: helgaas@kernel.org (Bjorn Helgaas)
To: linux-arm-kernel@lists.infradead.org
Subject: ks_dw_pcie_initiate_link_train() question
Date: Tue, 4 Oct 2016 12:40:51 -0500 [thread overview]
Message-ID: <20161004174051.GE3449@localhost> (raw)
Hi Murali,
This code looks suspicious. Can you comment?
void ks_dw_pcie_initiate_link_train(struct keystone_pcie *ks_pcie)
{
u32 val;
/* Disable Link training */
val = readl(ks_pcie->va_app_base + CMD_STATUS);
val &= ~LTSSM_EN_VAL;
writel(LTSSM_EN_VAL | val, ks_pcie->va_app_base + CMD_STATUS);
Here we cleared the LTSSM_EN_VAL bit in "val", but then we add it
right back in before writing it back to CMD_STATUS.
That looks like a cut and paste error to me, but of course I don't
know the hardware.
/* Initiate Link Training */
val = readl(ks_pcie->va_app_base + CMD_STATUS);
writel(LTSSM_EN_VAL | val, ks_pcie->va_app_base + CMD_STATUS);
}
next reply other threads:[~2016-10-04 17:40 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-04 17:40 Bjorn Helgaas [this message]
2016-10-04 17:40 ` ks_dw_pcie_initiate_link_train() question Bjorn Helgaas
2016-10-04 21:52 ` Murali Karicheri
2016-10-04 21:52 ` Murali Karicheri
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