Re: [PATCH v2 3/3] PCI: amlogic: Use AXG PCIE and shared MIPI/PCIE PHYs

Remi Pommarel
2019-12-24T16:33:23Z

On Tue, Dec 24, 2019 at 03:44:41PM +0530, Kishon Vijay Abraham I wrote:
> Hi,
>
> On 24/12/19 3:15 AM, Remi Pommarel wrote:
> > Now that PCIE PHY has been introduced for AXG, the whole has_shared_phy
> > logic can be mutualized between AXG and G12A platforms.
> >
> > This also makes use of the optional MIPI/PCIE shared fonctionality PHY
> > found on AXG platforms, which need to be used in order to have reliable
> > PCIE communications.
> >
> > Signed-off-by: Remi Pommarel <repk@triplefau.lt>
> > ---
> > drivers/pci/controller/dwc/pci-meson.c | 140 ++++++++-----------------
> > 1 file changed, 46 insertions(+), 94 deletions(-)
> >
> > diff --git a/drivers/pci/controller/dwc/pci-meson.c b/drivers/pci/controller/dwc/pci-meson.c
> > index 3772b02a5c55..3d12155c32f6 100644
> > --- a/drivers/pci/controller/dwc/pci-meson.c
> > +++ b/drivers/pci/controller/dwc/pci-meson.c
> > @@ -66,7 +66,6 @@
> > #define PORT_CLK_RATE 100000000UL
> > #define MAX_PAYLOAD_SIZE 256
> > #define MAX_READ_REQ_SIZE 256
> > -#define MESON_PCIE_PHY_POWERUP 0x1c
> > #define PCIE_RESET_DELAY 500
> > #define PCIE_SHARED_RESET 1
> > #define PCIE_NORMAL_RESET 0
> > @@ -81,26 +80,19 @@ enum pcie_data_rate {
> > struct meson_pcie_mem_res {
> > void __iomem *elbi_base;
> > void __iomem *cfg_base;
> > - void __iomem *phy_base;
> > };
> >
> > struct meson_pcie_clk_res {
> > struct clk *clk;
> > - struct clk *mipi_gate;
> > struct clk *port_clk;
> > struct clk *general_clk;
> > };
> >
> > struct meson_pcie_rc_reset {
> > - struct reset_control *phy;
> > struct reset_control *port;
> > struct reset_control *apb;
> > };
> >
> > -struct meson_pcie_param {
> > - bool has_shared_phy;
> > -};
> > -
> > struct meson_pcie {
> > struct dw_pcie pci;
> > struct meson_pcie_mem_res mem_res;
> > @@ -108,7 +100,7 @@ struct meson_pcie {
> > struct meson_pcie_rc_reset mrst;
> > struct gpio_desc *reset_gpio;
> > struct phy *phy;
> > - const struct meson_pcie_param *param;
> > + struct phy *shared_phy;
> > };
> >
> > static struct reset_control *meson_pcie_get_reset(struct meson_pcie *mp,
> > @@ -130,13 +122,6 @@ static int meson_pcie_get_resets(struct meson_pcie *mp)
> > {
> > struct meson_pcie_rc_reset *mrst = &mp->mrst;
> >
> > - if (!mp->param->has_shared_phy) {
> > - mrst->phy = meson_pcie_get_reset(mp, "phy", PCIE_SHARED_RESET);
> > - if (IS_ERR(mrst->phy))
> > - return PTR_ERR(mrst->phy);
> > - reset_control_deassert(mrst->phy);
> > - }
> > -
> > mrst->port = meson_pcie_get_reset(mp, "port", PCIE_NORMAL_RESET);
> > if (IS_ERR(mrst->port))
> > return PTR_ERR(mrst->port);
> > @@ -162,22 +147,6 @@ static void __iomem *meson_pcie_get_mem(struct platform_device *pdev,
> > return devm_ioremap_resource(dev, res);
> > }
> >
> > -static void __iomem *meson_pcie_get_mem_shared(struct platform_device *pdev,
> > - struct meson_pcie *mp,
> > - const char *id)
> > -{
> > - struct device *dev = mp->pci.dev;
> > - struct resource *res;
> > -
> > - res = platform_get_resource_byname(pdev, IORESOURCE_MEM, id);
> > - if (!res) {
> > - dev_err(dev, "No REG resource %s\n", id);
> > - return ERR_PTR(-ENXIO);
> > - }
> > -
> > - return devm_ioremap(dev, res->start, resource_size(res));
> > -}
> > -
> > static int meson_pcie_get_mems(struct platform_device *pdev,
> > struct meson_pcie *mp)
> > {
> > @@ -189,14 +158,6 @@ static int meson_pcie_get_mems(struct platform_device *pdev,
> > if (IS_ERR(mp->mem_res.cfg_base))
> > return PTR_ERR(mp->mem_res.cfg_base);
> >
> > - /* Meson AXG SoC has two PCI controllers use same phy register */
> > - if (!mp->param->has_shared_phy) {
> > - mp->mem_res.phy_base =
> > - meson_pcie_get_mem_shared(pdev, mp, "phy");
> > - if (IS_ERR(mp->mem_res.phy_base))
> > - return PTR_ERR(mp->mem_res.phy_base);
> > - }
> > -
> > return 0;
> > }
> >
> > @@ -204,20 +165,40 @@ static int meson_pcie_power_on(struct meson_pcie *mp)
> > {
> > int ret = 0;
> >
> > - if (mp->param->has_shared_phy) {
> > - ret = phy_init(mp->phy);
> > - if (ret)
> > - return ret;
> > + ret = phy_init(mp->phy);
> > + if (ret)
> > + goto err;
> >
> > - ret = phy_power_on(mp->phy);
> > - if (ret) {
> > - phy_exit(mp->phy);
> > - return ret;
> > - }
> > - } else
> > - writel(MESON_PCIE_PHY_POWERUP, mp->mem_res.phy_base);
> > + ret = phy_init(mp->shared_phy);
> > + if (ret)
> > + goto exit;
> > +
> > + ret = phy_power_on(mp->phy);
> > + if (ret)
> > + goto shared_exit;
> > +
> > + ret = phy_power_on(mp->shared_phy);
> > + if (ret)
> > + goto power_off;
> >
> > return 0;
> > +
> > +power_off:
> > + phy_power_off(mp->phy);
> > +shared_exit:
> > + phy_exit(mp->shared_phy);
> > +exit:
> > + phy_exit(mp->phy);
> > +err:
> > + return ret;
> > +}
> > +
> > +static void meson_pcie_power_off(struct meson_pcie *mp)
> > +{
> > + phy_power_off(mp->shared_phy);
> > + phy_power_off(mp->phy);
> > + phy_exit(mp->shared_phy);
> > + phy_exit(mp->phy);
> > }
> >
> > static int meson_pcie_reset(struct meson_pcie *mp)
> > @@ -225,16 +206,13 @@ static int meson_pcie_reset(struct meson_pcie *mp)
> > struct meson_pcie_rc_reset *mrst = &mp->mrst;
> > int ret = 0;
> >
> > - if (mp->param->has_shared_phy) {
> > - ret = phy_reset(mp->phy);
> > - if (ret)
> > - return ret;
> > - } else {
> > - reset_control_assert(mrst->phy);
> > - udelay(PCIE_RESET_DELAY);
> > - reset_control_deassert(mrst->phy);
> > - udelay(PCIE_RESET_DELAY);
> > - }
> > + ret = phy_reset(mp->phy);
> > + if (ret)
> > + return ret;
> > +
> > + ret = phy_reset(mp->shared_phy);
> > + if (ret)
> > + return ret;
> >
> > reset_control_assert(mrst->port);
> > reset_control_assert(mrst->apb);
> > @@ -286,12 +264,6 @@ static int meson_pcie_probe_clocks(struct meson_pcie *mp)
> > if (IS_ERR(res->port_clk))
> > return PTR_ERR(res->port_clk);
> >
> > - if (!mp->param->has_shared_phy) {
> > - res->mipi_gate = meson_pcie_probe_clock(dev, "mipi", 0);
> > - if (IS_ERR(res->mipi_gate))
> > - return PTR_ERR(res->mipi_gate);
> > - }
> > -
> > res->general_clk = meson_pcie_probe_clock(dev, "general", 0);
> > if (IS_ERR(res->general_clk))
> > return PTR_ERR(res->general_clk);
> > @@ -562,7 +534,6 @@ static const struct dw_pcie_ops dw_pcie_ops = {
> >
> > static int meson_pcie_probe(struct platform_device *pdev)
> > {
> > - const struct meson_pcie_param *match_data;
> > struct device *dev = &pdev->dev;
> > struct dw_pcie *pci;
> > struct meson_pcie *mp;
> > @@ -576,18 +547,13 @@ static int meson_pcie_probe(struct platform_device *pdev)
> > pci->dev = dev;
> > pci->ops = &dw_pcie_ops;
> >
> > - match_data = of_device_get_match_data(dev);
> > - if (!match_data) {
> > - dev_err(dev, "failed to get match data\n");
> > - return -ENODEV;
> > - }
> > - mp->param = match_data;
> > + mp->phy = devm_phy_get(dev, "pcie");
> > + if (IS_ERR(mp->phy))
> > + return PTR_ERR(mp->phy);
> >
> > - if (mp->param->has_shared_phy) {
> > - mp->phy = devm_phy_get(dev, "pcie");
> > - if (IS_ERR(mp->phy))
> > - return PTR_ERR(mp->phy);
> > - }
> > + mp->shared_phy = devm_phy_optional_get(dev, "shared");
> > + if (IS_ERR(mp->phy))
> > + return PTR_ERR(mp->phy);
>
> This also requires dt-binding updation.Is PCIe connected to two
> different PHYs here?

Not exactly, it is that the PCIE PHY is using some non documented bits
from the range of the MIPI one. But now that I have read about syscon it
seems that those registers are defined to be handled by syscon subsystem
in the device tree.

Thus I think It would make much more sense to remove the shared MIPI/PCIE
PHY driver in patch 1/3 and set the appropriate bits in the PCIE PHY
driver itself from patch 2/3 through syscon subsystem.

Sorry for the noise, will send v3 with only 1 PHY driver and appropriate
binding documentation.

Thanks,

--
Remi