Re: [PATCH v4 7/7] PCI: amlogic: Use AXG PCIE and shared MIPI/PCIE PHYs

From: Remi Pommarel
Date: Wed Jan 15 2020 - 08:31:42 EST

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In reply to: Neil Armstrong: "Re: [PATCH v4 7/7] PCI: amlogic: Use AXG PCIE and shared MIPI/PCIE PHYs"
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On Wed, Jan 15, 2020 at 01:30:06PM +0100, Neil Armstrong wrote:
> On 15/01/2020 13:29, 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@xxxxxxxxxxxx>
> > ---
> > 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..309e75f554ac 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->shared_phy))
> > + return PTR_ERR(mp->shared_phy);
>
> This "shared" phy doesn't appear in patch 3 (bindings) !
>
> Not sure it's the best way to do this, maybe you could chain the MIPI
> phy from the PCIE phy instead, so it's the PCIE phy to enable/power/reset the
> MIPI PHY instead of the PCIe driver.

Sure will do.

>
> But still, here you don't really model the MIPI PHY, it uses way more than
> a register in HHI... so at least you should add all the resources needed
> if you wanted to model a true MIPI PHY. i.e. MIPI PHY registers, clocks, resets
> & co if you want to model the MIPI PHY as is.

As discussed on IRC, I will rename this as mipi-analog-phy to match the
datasheet and at some point if some platform ever needed MIPI feature,
a mipi-digital-phy driver that handles the registers that are not in
HHI as well as the clocks, resets, ... could be added.

Thanks,

--
Remi

>
> Neil
>
> >
> > mp->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
> > if (IS_ERR(mp->reset_gpio)) {
> > @@ -636,30 +602,16 @@ static int meson_pcie_probe(struct platform_device *pdev)
> > return 0;
> >
> > err_phy:
> > - if (mp->param->has_shared_phy) {
> > - phy_power_off(mp->phy);
> > - phy_exit(mp->phy);
> > - }
> > -
> > + meson_pcie_power_off(mp);
> > return ret;
> > }
> >
> > -static struct meson_pcie_param meson_pcie_axg_param = {
> > - .has_shared_phy = false,
> > -};
> > -
> > -static struct meson_pcie_param meson_pcie_g12a_param = {
> > - .has_shared_phy = true,
> > -};
> > -
> > static const struct of_device_id meson_pcie_of_match[] = {
> > {
> > .compatible = "amlogic,axg-pcie",
> > - .data = &meson_pcie_axg_param,
> > },
> > {
> > .compatible = "amlogic,g12a-pcie",
> > - .data = &meson_pcie_g12a_param,
> > },
> > {},
> > };
> >
>

Next message: David Howells: "[RFC PATCH 06/14] keys: Add a notification facility [ver #3]"
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In reply to: Neil Armstrong: "Re: [PATCH v4 7/7] PCI: amlogic: Use AXG PCIE and shared MIPI/PCIE PHYs"
Next in thread: Remi Pommarel: "[PATCH v4 3/7] dt-bindings: PCI: meson: Update PCIE bindings documentation"
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