| Message ID | 20150612202008.GI23119@google.com |
|---|---|
| State | Accepted |
| Headers | show |
On 6/12/2015 1:20 PM, Bjorn Helgaas wrote: > Hi Troy, > > On Fri, Jun 05, 2015 at 03:37:44PM -0700, Troy Kisky wrote: >> Currently, the timeout is never detected as count >> has a value of -1 if a timeout happens, but the code is checking >> for 0. Also, this patch removes the unneeded final wait >> if a timeout occurs. >> >> Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com> >> --- >> drivers/pci/host/pci-imx6.c | 18 ++++++++++-------- >> 1 file changed, 10 insertions(+), 8 deletions(-) >> >> diff --git a/drivers/pci/host/pci-imx6.c b/drivers/pci/host/pci-imx6.c >> index fdb9536..51be92c 100644 >> --- a/drivers/pci/host/pci-imx6.c >> +++ b/drivers/pci/host/pci-imx6.c >> @@ -398,20 +398,22 @@ static int imx6_pcie_start_link(struct pcie_port *pp) >> writel(tmp, pp->dbi_base + PCIE_LINK_WIDTH_SPEED_CONTROL); >> >> count = 200; >> - while (count--) { >> + while (1) { >> tmp = readl(pp->dbi_base + PCIE_LINK_WIDTH_SPEED_CONTROL); >> /* Test if the speed change finished. */ >> - if (!(tmp & PORT_LOGIC_SPEED_CHANGE)) >> + if (!(tmp & PORT_LOGIC_SPEED_CHANGE)) { >> + /* Make sure link training is finished as well! */ >> + ret = imx6_pcie_wait_for_link(pp); >> + break; >> + } >> + if (count-- == 0) { >> + dev_err(pp->dev, "Speed change timeout\n"); >> + ret = -EINVAL; >> break; >> + } >> usleep_range(100, 1000); >> } >> >> - /* Make sure link training is finished as well! */ >> - if (count) >> - ret = imx6_pcie_wait_for_link(pp); >> - else >> - ret = -EINVAL; >> - >> if (ret) { >> dev_err(pp->dev, "Failed to bring link up!\n"); >> } else { > > This looks fine functionally, but I propose the following slight > rearrangement because I have another patch that makes all the > "wait_for_link" timeout loops look similar, and this loop might as > well be similar, too. > > Unrelated to your patch, but noticed while doing this: what's the magic > constant 0x80 here? > > + tmp = readl(pp->dbi_base + 0x80); > > Is that correct? Can we add a symbolic name for it? > > Bjorn > The name in the manual for +x80 is PCIE_RC_LCSR - Link Control and Status Register -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/pci/host/pci-imx6.c b/drivers/pci/host/pci-imx6.c index fdb9536..2bbd38d 100644 --- a/drivers/pci/host/pci-imx6.c +++ b/drivers/pci/host/pci-imx6.c @@ -352,6 +352,23 @@ static int imx6_pcie_wait_for_link(struct pcie_port *pp) return 0; } +static int imx6_pcie_wait_for_speed_change(struct pcie_port *pp) +{ + uint32_t tmp; + unsigned int retries; + + for (retries = 0; retries < 200; retries++) + tmp = readl(pp->dbi_base + PCIE_LINK_WIDTH_SPEED_CONTROL); + /* Test if the speed change finished. */ + if (!(tmp & PORT_LOGIC_SPEED_CHANGE)) + return 0; + usleep_range(100, 1000); + } + + dev_err(pp->dev, "Speed change timeout\n"); + return -EINVAL; +} + static irqreturn_t imx6_pcie_msi_handler(int irq, void *arg) { struct pcie_port *pp = arg; @@ -363,7 +380,7 @@ static int imx6_pcie_start_link(struct pcie_port *pp) { struct imx6_pcie *imx6_pcie = to_imx6_pcie(pp); uint32_t tmp; - int ret, count; + int ret; /* * Force Gen1 operation when starting the link. In case the link is @@ -397,29 +414,22 @@ static int imx6_pcie_start_link(struct pcie_port *pp) tmp |= PORT_LOGIC_SPEED_CHANGE; writel(tmp, pp->dbi_base + PCIE_LINK_WIDTH_SPEED_CONTROL); - count = 200; - while (count--) { - tmp = readl(pp->dbi_base + PCIE_LINK_WIDTH_SPEED_CONTROL); - /* Test if the speed change finished. */ - if (!(tmp & PORT_LOGIC_SPEED_CHANGE)) - break; - usleep_range(100, 1000); + ret = imx6_pcie_wait_for_speed_change(pp); + if (ret) { + dev_err(pp->dev, "Failed to bring link up!\n"); + return ret; } /* Make sure link training is finished as well! */ - if (count) - ret = imx6_pcie_wait_for_link(pp); - else - ret = -EINVAL; - + ret = imx6_pcie_wait_for_link(pp); if (ret) { dev_err(pp->dev, "Failed to bring link up!\n"); - } else { - tmp = readl(pp->dbi_base + 0x80); - dev_dbg(pp->dev, "Link up, Gen=%i\n", (tmp >> 16) & 0xf); + return ret; } - return ret; + tmp = readl(pp->dbi_base + 0x80); + dev_dbg(pp->dev, "Link up, Gen=%i\n", (tmp >> 16) & 0xf); + return 0; } static void imx6_pcie_host_init(struct pcie_port *pp)