Re: [PATCH 7/7] PCI: dwc: qcom: Add support for IPQ8074 PCIe controller
From: Varadarajan Narayanan
Date: Tue Jul 18 2017 - 05:58:50 EST
On Mon, Jul 17, 2017 at 03:07:18PM -0700, Bjorn Andersson wrote:
> On Mon 17 Jul 05:04 PDT 2017, Varadarajan Narayanan wrote:
>
> > Add support for the IPQ8074 PCIe controller. IPQ8074 supports
> > Gen 1/2, one lane, two PCIe root complex with support for MSI and
> > legacy interrupts, and it conforms to PCI Express Base 2.1
> > specification.
> >
> > The core init is the similar to the existing SoC, however the
> > clocks and reset lines differ.
> >
> > Signed-off-by: smuthayy <smuthayy@xxxxxxxxxxxxxx>
> > Signed-off-by: Varadarajan Narayanan <varada@xxxxxxxxxxxxxx>
> > ---
> > drivers/pci/dwc/pcie-qcom.c | 259 ++++++++++++++++++++++++++++++++++++++++++++
> > 1 file changed, 259 insertions(+)
> >
> > diff --git a/drivers/pci/dwc/pcie-qcom.c b/drivers/pci/dwc/pcie-qcom.c
> > index d15657d..c1fa356 100644
> > --- a/drivers/pci/dwc/pcie-qcom.c
> > +++ b/drivers/pci/dwc/pcie-qcom.c
> > @@ -37,6 +37,20 @@
> > #include "pcie-designware.h"
> >
> > #define PCIE20_PARF_SYS_CTRL 0x00
> > +#define MST_WAKEUP_EN BIT(13)
> > +#define SLV_WAKEUP_EN BIT(12)
> > +#define MSTR_ACLK_CGC_DIS BIT(10)
> > +#define SLV_ACLK_CGC_DIS BIT(9)
> > +#define CORE_CLK_CGC_DIS BIT(6)
> > +#define AUX_PWR_DET BIT(4)
> > +#define L23_CLK_RMV_DIS BIT(2)
> > +#define L1_CLK_RMV_DIS BIT(1)
> > +
> > +#define PCIE20_COMMAND_STATUS 0x04
> > +#define CMD_BME_VAL 0x4
> > +#define PCIE20_DEVICE_CONTROL2_STATUS2 0x98
> > +#define PCIE_CAP_CPL_TIMEOUT_DISABLE 0x10
> > +
> > #define PCIE20_PARF_PHY_CTRL 0x40
> > #define PCIE20_PARF_PHY_REFCLK 0x4C
> > #define PCIE20_PARF_DBI_BASE_ADDR 0x168
> > @@ -58,9 +72,22 @@
> > #define CFG_BRIDGE_SB_INIT BIT(0)
> >
> > #define PCIE20_CAP 0x70
> > +#define PCIE20_CAP_LINK_CAPABILITIES (PCIE20_CAP + 0xC)
> > +#define PCIE20_CAP_LINK_1 (PCIE20_CAP + 0x14)
> > +#define PCIE_CAP_LINK1_VAL 0x2fd7f
> > +
> > +#define PCIE20_PARF_Q2A_FLUSH 0x1AC
> > +
> > +#define PCIE20_MISC_CONTROL_1_REG 0x8BC
> > +#define DBI_RO_WR_EN 1
> >
> > #define PERST_DELAY_US 1000
> >
> > +#define AXI_CLK_RATE 200000000
> > +
> > +#define PCIE20_v3_PARF_SLV_ADDR_SPACE_SIZE 0x358
> > +#define SLV_ADDR_SPACE_SZ 0x10000000
> > +
> > struct qcom_pcie_resources_v0 {
> > struct clk *iface_clk;
> > struct clk *core_clk;
> > @@ -110,11 +137,26 @@ struct qcom_pcie_resources_v3 {
> > struct reset_control *phy_ahb_reset;
> > };
> >
> > +struct qphy_reset {
> > + struct reset_control *rst;
> > + char *name;
> > +};
> > +
> > +struct qcom_pcie_resources_v4 {
> > + struct clk *sys_noc_clk;
> > + struct clk *axi_m_clk;
> > + struct clk *axi_s_clk;
> > + struct clk *ahb_clk;
> > + struct clk *aux_clk;
> > + struct qphy_reset rst[7];
>
> Just store the struct reset_control here directly, carrying the name
> doesn't serve much of a purpose - and it clutters the code.
Ok.
> > +};
>
> Can you confirm that this is actually version 4 of this block? Or are we
> just incrementing an arbitrary number here?
This is not exactly the 4th version of the block. However, it is
a different version than the ones that are already supported in
this driver. Since the existing driver didn't exactly tie it with
the block IP version, I too followed the same versioning
convention.
> > +
> > union qcom_pcie_resources {
> > struct qcom_pcie_resources_v0 v0;
> > struct qcom_pcie_resources_v1 v1;
> > struct qcom_pcie_resources_v2 v2;
> > struct qcom_pcie_resources_v3 v3;
> > + struct qcom_pcie_resources_v4 v4;
> > };
> >
> > struct qcom_pcie;
> > @@ -139,6 +181,16 @@ struct qcom_pcie {
> >
> > #define to_qcom_pcie(x) dev_get_drvdata((x)->dev)
> >
> > +static inline void
> > +writel_masked(void __iomem *addr, u32 clear_mask, u32 set_mask)
>
> This function name is very generic and in the two places you call it
> set_mask is 0. So please just inline this.
Ok.
> > +{
> > + u32 val = readl(addr);
> > +
> > + val &= ~clear_mask;
> > + val |= set_mask;
> > + writel(val, addr);
> > +}
> > +
> > static void qcom_ep_reset_assert(struct qcom_pcie *pcie)
> > {
> > gpiod_set_value(pcie->reset, 1);
> > @@ -884,6 +936,205 @@ static int qcom_pcie_init_v3(struct qcom_pcie *pcie)
> > return ret;
> > }
> >
> > +static int qcom_pcie_get_resources_v4(struct qcom_pcie *pcie)
> > +{
> > + struct qcom_pcie_resources_v4 *res = &pcie->res.v4;
> > + struct dw_pcie *pci = pcie->pci;
> > + struct device *dev = pci->dev;
> > + int i;
> > +
> > + res->sys_noc_clk = devm_clk_get(dev, "sys_noc");
> > + if (IS_ERR(res->sys_noc_clk))
> > + return PTR_ERR(res->sys_noc_clk);
> > +
> > + res->axi_m_clk = devm_clk_get(dev, "axi_m");
> > + if (IS_ERR(res->axi_m_clk))
> > + return PTR_ERR(res->axi_m_clk);
> > +
> > + res->axi_s_clk = devm_clk_get(dev, "axi_s");
> > + if (IS_ERR(res->axi_s_clk))
> > + return PTR_ERR(res->axi_s_clk);
> > +
> > + res->ahb_clk = devm_clk_get(dev, "ahb");
> > + if (IS_ERR(res->ahb_clk))
> > + return PTR_ERR(res->ahb_clk);
> > +
> > + res->aux_clk = devm_clk_get(dev, "aux");
> > + if (IS_ERR(res->aux_clk))
> > + return PTR_ERR(res->aux_clk);
> > +
> > + res->rst[0].name = "axi_m";
> > + res->rst[1].name = "axi_s";
> > + res->rst[2].name = "pipe";
> > + res->rst[3].name = "axi_m_sticky";
> > + res->rst[4].name = "sticky";
> > + res->rst[5].name = "ahb";
> > + res->rst[6].name = "sleep";
> > +
> > + for (i = 0; i < ARRAY_SIZE(res->rst); i++) {
> > + res->rst[i].rst = devm_reset_control_get(dev, res->rst[i].name);
> > + if (IS_ERR(res->rst[i].rst))
> > + return PTR_ERR(res->rst[i].rst);
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static void qcom_pcie_deinit_v4(struct qcom_pcie *pcie)
> > +{
> > + struct qcom_pcie_resources_v4 *res = &pcie->res.v4;
> > +
> > + clk_disable_unprepare(res->sys_noc_clk);
> > + clk_disable_unprepare(res->axi_m_clk);
> > + clk_disable_unprepare(res->axi_s_clk);
> > + clk_disable_unprepare(res->ahb_clk);
> > + clk_disable_unprepare(res->aux_clk);
> > +}
> > +
> > +static int qcom_pcie_enable_resources_v4(struct qcom_pcie *pcie)
> > +{
> > + struct qcom_pcie_resources_v4 *res = &pcie->res.v4;
> > + struct dw_pcie *pci = pcie->pci;
> > + struct device *dev = pci->dev;
> > + int ret;
> > +
> > + ret = clk_prepare_enable(res->sys_noc_clk);
> > + if (ret) {
> > + dev_err(dev, "cannot prepare/enable core clock\n");
> > + return ret;
> > + }
>
> Should these clocks really be handled explicitly in the driver? Are
> these not the bus clocks, to be handled by "msm_bus"?
This not the bus clock. This clock is for the Bus Interface Unit
between the PCIe module and the System NOC.
> > +
> > + ret = clk_prepare_enable(res->axi_m_clk);
> > + if (ret) {
> > + dev_err(dev, "cannot prepare/enable core clock\n");
> > + goto err_clk_axi_m;
> > + }
> > +
> > + ret = clk_set_rate(res->axi_m_clk, AXI_CLK_RATE);
> > + if (ret) {
> > + dev_err(dev, "MClk rate set failed (%d)\n", ret);
> > + goto err_clk_axi_m;
> > + }
> > +
> > + ret = clk_prepare_enable(res->axi_s_clk);
> > + if (ret) {
> > + dev_err(dev, "cannot prepare/enable axi slave clock\n");
> > + goto err_clk_axi_s;
> > + }
> > +
> > + ret = clk_set_rate(res->axi_s_clk, AXI_CLK_RATE);
> > + if (ret) {
> > + dev_err(dev, "MClk rate set failed (%d)\n", ret);
> > + goto err_clk_axi_s;
> > + }
> > +
> > + ret = clk_prepare_enable(res->ahb_clk);
> > + if (ret) {
> > + dev_err(dev, "cannot prepare/enable ahb clock\n");
> > + goto err_clk_ahb;
> > + }
> > +
> > + ret = clk_prepare_enable(res->aux_clk);
> > + if (ret) {
> > + dev_err(dev, "cannot prepare/enable aux clock\n");
> > + goto err_clk_aux;
> > + }
> > +
> > + udelay(1);
> > +
> > + return 0;
> > +
> > +err_clk_aux:
> > + clk_disable_unprepare(res->ahb_clk);
> > +err_clk_ahb:
> > + clk_disable_unprepare(res->axi_s_clk);
> > +err_clk_axi_s:
> > + clk_disable_unprepare(res->axi_m_clk);
> > +err_clk_axi_m:
> > + clk_disable_unprepare(res->sys_noc_clk);
> > +
> > + return ret;
> > +}
> > +
> > +static inline int qphy_reset_control(struct qcom_pcie *pcie,
> > + struct qphy_reset *r,
> > + bool assert)
> > +{
> > + int ret;
> > +
> > + if (assert)
> > + ret = reset_control_assert(r->rst);
> > + else
> > + ret = reset_control_deassert(r->rst);
> > +
> > + if (ret)
> > + dev_err(pcie->pci->dev, "%s: reset %s failed for %s\n",
> > + __func__, assert ? "assert" : "deassert", r->name);
> > +
> > + return ret;
> > +}
> > +
> > +static void qcom_pcie_v4_reset(struct qcom_pcie *pcie)
> > +{
> > + struct qcom_pcie_resources_v4 *res = &pcie->res.v4;
> > + struct qphy_reset *qphy_rst = &res->rst[0];
>
> &res->rst[0] is supposed to be written as res->rst, but that's exactly
> the same number of characters to type as your local variable. So just
> skip the variable.
Ok.
> > + int i;
> > +
> > + for (i = 0; i < ARRAY_SIZE(res->rst); i++)
> > + if (qphy_reset_control(pcie, &qphy_rst[i], true))
>
> This is a complicated way of saying:
> if (reset_control_assert(qphy_rst[i].rst))
Ok, will remove the helper function.
> > + return;
>
> You should most definitely propagate this error.
Ok.
> > +
> > + usleep_range(10000, 12000); /* wait 12ms */
>
> This is not 12ms, this is 10-12ms. This is a _long_ time to usleep, how
> about just msleep(20) instead?
Ok.
> > +
> > + for (i = 0; i < ARRAY_SIZE(res->rst); i++)
> > + if (qphy_reset_control(pcie, &qphy_rst[i], false))
>
> Same as above, this just write:
> if (reset_control_deassert(qphy_rst[i].rst))
Ok.
> > + return;
> > +
> > + usleep_range(10000, 12000); /* wait 12ms */
> > + wmb(); /* ensure data is written to hw register */
>
> wmb() ensures ordering of writes, it does not wait for data to reach the
> hardware registers.
Ok. Will remove it.
> > +}
> > +
> > +static int qcom_pcie_init_v4(struct qcom_pcie *pcie)
> > +{
> > + struct dw_pcie *pci = pcie->pci;
> > + int ret;
> > +
> > + qcom_pcie_v4_reset(pcie);
> > + qcom_ep_reset_assert(pcie);
> > +
> > + ret = qcom_pcie_enable_resources_v4(pcie);
> > + if (ret)
> > + return ret;
> > +
> > + writel(SLV_ADDR_SPACE_SZ, pcie->parf +
> > + PCIE20_v3_PARF_SLV_ADDR_SPACE_SIZE);
> > +
> > + ret = phy_power_on(pcie->phy);
> > + if (ret)
>
> This will leave all the resources enabled, you should issue a deinit
> here..
Ok.
Thanks
Varada
> > + return ret;
> > +
> > + writel_masked(pcie->parf + PCIE20_PARF_PHY_CTRL, BIT(0), 0);
> > +
>
> Regards,
> Bjorn
--
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