* [PATCH] PCI: rockchip-host: Fix rockchip_pcie_host_init_port() PERST handling
@ 2024-03-29 8:44 ` Damien Le Moal
0 siblings, 0 replies; 4+ messages in thread
From: Damien Le Moal @ 2024-03-29 8:44 UTC (permalink / raw)
To: Shawn Lin, Krzysztof Wilczyński, Bjorn Helgaas,
Heiko Stuebner, linux-pci
Cc: linux-rockchip
The PCI specifications mandate that PERST be asserted for at least
100ms. Make sure that is done in rockchip_pcie_host_init_port() by
adding a 100ms sleep before bringing back PESRT signal to high using the
ep_gpio GPIO. Comments are also added to clarify this behavior.
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
---
drivers/pci/controller/pcie-rockchip-host.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/pci/controller/pcie-rockchip-host.c b/drivers/pci/controller/pcie-rockchip-host.c
index 300b9dc85ecc..d526b9d26c18 100644
--- a/drivers/pci/controller/pcie-rockchip-host.c
+++ b/drivers/pci/controller/pcie-rockchip-host.c
@@ -294,6 +294,7 @@ static int rockchip_pcie_host_init_port(struct rockchip_pcie *rockchip)
int err, i = MAX_LANE_NUM;
u32 status;
+ /* Assert PERST */
gpiod_set_value_cansleep(rockchip->ep_gpio, 0);
err = rockchip_pcie_init_port(rockchip);
@@ -322,6 +323,11 @@ static int rockchip_pcie_host_init_port(struct rockchip_pcie *rockchip)
rockchip_pcie_write(rockchip, PCIE_CLIENT_LINK_TRAIN_ENABLE,
PCIE_CLIENT_CONFIG);
+ /*
+ * PCIe specifications mandate that PERST be asserted for at
+ * least 100ms.
+ */
+ msleep(100);
gpiod_set_value_cansleep(rockchip->ep_gpio, 1);
/* 500ms timeout value should be enough for Gen1/2 training */
--
2.44.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH] PCI: rockchip-host: Fix rockchip_pcie_host_init_port() PERST handling
@ 2024-03-29 8:44 ` Damien Le Moal
0 siblings, 0 replies; 4+ messages in thread
From: Damien Le Moal @ 2024-03-29 8:44 UTC (permalink / raw)
To: Shawn Lin, Krzysztof Wilczyński, Bjorn Helgaas,
Heiko Stuebner, linux-pci
Cc: linux-rockchip
The PCI specifications mandate that PERST be asserted for at least
100ms. Make sure that is done in rockchip_pcie_host_init_port() by
adding a 100ms sleep before bringing back PESRT signal to high using the
ep_gpio GPIO. Comments are also added to clarify this behavior.
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
---
drivers/pci/controller/pcie-rockchip-host.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/pci/controller/pcie-rockchip-host.c b/drivers/pci/controller/pcie-rockchip-host.c
index 300b9dc85ecc..d526b9d26c18 100644
--- a/drivers/pci/controller/pcie-rockchip-host.c
+++ b/drivers/pci/controller/pcie-rockchip-host.c
@@ -294,6 +294,7 @@ static int rockchip_pcie_host_init_port(struct rockchip_pcie *rockchip)
int err, i = MAX_LANE_NUM;
u32 status;
+ /* Assert PERST */
gpiod_set_value_cansleep(rockchip->ep_gpio, 0);
err = rockchip_pcie_init_port(rockchip);
@@ -322,6 +323,11 @@ static int rockchip_pcie_host_init_port(struct rockchip_pcie *rockchip)
rockchip_pcie_write(rockchip, PCIE_CLIENT_LINK_TRAIN_ENABLE,
PCIE_CLIENT_CONFIG);
+ /*
+ * PCIe specifications mandate that PERST be asserted for at
+ * least 100ms.
+ */
+ msleep(100);
gpiod_set_value_cansleep(rockchip->ep_gpio, 1);
/* 500ms timeout value should be enough for Gen1/2 training */
--
2.44.0
_______________________________________________
Linux-rockchip mailing list
Linux-rockchip@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-rockchip
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] PCI: rockchip-host: Fix rockchip_pcie_host_init_port() PERST handling
2024-03-29 8:44 ` Damien Le Moal
@ 2024-03-29 12:46 ` Bjorn Helgaas
-1 siblings, 0 replies; 4+ messages in thread
From: Bjorn Helgaas @ 2024-03-29 12:46 UTC (permalink / raw)
To: Damien Le Moal
Cc: Shawn Lin, Krzysztof Wilczyński, Bjorn Helgaas,
Heiko Stuebner, linux-pci, linux-rockchip
Observing the timing is the important thing here, if you can wedge
that into the subject somehow.
On Fri, Mar 29, 2024 at 05:44:07PM +0900, Damien Le Moal wrote:
> The PCI specifications mandate that PERST be asserted for at least
> 100ms. Make sure that is done in rockchip_pcie_host_init_port() by
> adding a 100ms sleep before bringing back PESRT signal to high using the
> ep_gpio GPIO. Comments are also added to clarify this behavior.
"PERST#" in spec, and to make the "assert" and "set value to 0" all
match up.
s/PESRT/PERST#/
> Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
> ---
> drivers/pci/controller/pcie-rockchip-host.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/drivers/pci/controller/pcie-rockchip-host.c b/drivers/pci/controller/pcie-rockchip-host.c
> index 300b9dc85ecc..d526b9d26c18 100644
> --- a/drivers/pci/controller/pcie-rockchip-host.c
> +++ b/drivers/pci/controller/pcie-rockchip-host.c
> @@ -294,6 +294,7 @@ static int rockchip_pcie_host_init_port(struct rockchip_pcie *rockchip)
> int err, i = MAX_LANE_NUM;
> u32 status;
>
> + /* Assert PERST */
> gpiod_set_value_cansleep(rockchip->ep_gpio, 0);
>
> err = rockchip_pcie_init_port(rockchip);
> @@ -322,6 +323,11 @@ static int rockchip_pcie_host_init_port(struct rockchip_pcie *rockchip)
> rockchip_pcie_write(rockchip, PCIE_CLIENT_LINK_TRAIN_ENABLE,
> PCIE_CLIENT_CONFIG);
>
> + /*
> + * PCIe specifications mandate that PERST be asserted for at
> + * least 100ms.
> + */
> + msleep(100);
Specific rev, section citation? And a name for the parameter if there
is one (T_PVPERL, etc). And hopefully a macro along the lines of
PCIE_T_PVPERL_MS since this isn't rockchip-specific.
> gpiod_set_value_cansleep(rockchip->ep_gpio, 1);
>
> /* 500ms timeout value should be enough for Gen1/2 training */
> --
> 2.44.0
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] PCI: rockchip-host: Fix rockchip_pcie_host_init_port() PERST handling
@ 2024-03-29 12:46 ` Bjorn Helgaas
0 siblings, 0 replies; 4+ messages in thread
From: Bjorn Helgaas @ 2024-03-29 12:46 UTC (permalink / raw)
To: Damien Le Moal
Cc: Shawn Lin, Krzysztof Wilczyński, Bjorn Helgaas,
Heiko Stuebner, linux-pci, linux-rockchip
Observing the timing is the important thing here, if you can wedge
that into the subject somehow.
On Fri, Mar 29, 2024 at 05:44:07PM +0900, Damien Le Moal wrote:
> The PCI specifications mandate that PERST be asserted for at least
> 100ms. Make sure that is done in rockchip_pcie_host_init_port() by
> adding a 100ms sleep before bringing back PESRT signal to high using the
> ep_gpio GPIO. Comments are also added to clarify this behavior.
"PERST#" in spec, and to make the "assert" and "set value to 0" all
match up.
s/PESRT/PERST#/
> Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
> ---
> drivers/pci/controller/pcie-rockchip-host.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/drivers/pci/controller/pcie-rockchip-host.c b/drivers/pci/controller/pcie-rockchip-host.c
> index 300b9dc85ecc..d526b9d26c18 100644
> --- a/drivers/pci/controller/pcie-rockchip-host.c
> +++ b/drivers/pci/controller/pcie-rockchip-host.c
> @@ -294,6 +294,7 @@ static int rockchip_pcie_host_init_port(struct rockchip_pcie *rockchip)
> int err, i = MAX_LANE_NUM;
> u32 status;
>
> + /* Assert PERST */
> gpiod_set_value_cansleep(rockchip->ep_gpio, 0);
>
> err = rockchip_pcie_init_port(rockchip);
> @@ -322,6 +323,11 @@ static int rockchip_pcie_host_init_port(struct rockchip_pcie *rockchip)
> rockchip_pcie_write(rockchip, PCIE_CLIENT_LINK_TRAIN_ENABLE,
> PCIE_CLIENT_CONFIG);
>
> + /*
> + * PCIe specifications mandate that PERST be asserted for at
> + * least 100ms.
> + */
> + msleep(100);
Specific rev, section citation? And a name for the parameter if there
is one (T_PVPERL, etc). And hopefully a macro along the lines of
PCIE_T_PVPERL_MS since this isn't rockchip-specific.
> gpiod_set_value_cansleep(rockchip->ep_gpio, 1);
>
> /* 500ms timeout value should be enough for Gen1/2 training */
> --
> 2.44.0
>
_______________________________________________
Linux-rockchip mailing list
Linux-rockchip@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-rockchip
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2024-03-29 12:48 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2024-03-29 8:44 [PATCH] PCI: rockchip-host: Fix rockchip_pcie_host_init_port() PERST handling Damien Le Moal
2024-03-29 8:44 ` Damien Le Moal
2024-03-29 12:46 ` Bjorn Helgaas
2024-03-29 12:46 ` Bjorn Helgaas
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