Re: [PATCH v2 2/6] PCI: qcom: add support for IPQ60xx PCIe controller

Rob Herring
2021-08-25T13:41:24Z

On Wed, Aug 25, 2021 at 6:25 AM Baruch Siach <baruch@tkos.co.il> wrote:
>
> Hi Rob,
>
> On Fri, Aug 06 2021, Rob Herring wrote:
> > On Wed, May 5, 2021 at 3:18 AM Baruch Siach <baruch@tkos.co.il> wrote:
> >>
> >> From: Selvam Sathappan Periakaruppan <speriaka@codeaurora.org>
> >>
> >> IPQ60xx series of SoCs have one port of PCIe gen 3. Add support for that
> >> platform.
> >>
> >> The code is based on downstream Codeaurora kernel v5.4. Split out the
> >> DBI registers access part from .init into .post_init. DBI registers are
> >> only accessible after phy_power_on().
> >>
> >> Signed-off-by: Selvam Sathappan Periakaruppan <speriaka@codeaurora.org>
> >> Signed-off-by: Baruch Siach <baruch@tkos.co.il>
> >> ---
> >> v2:
> >> * Drop ATU configuration; rely on common code instead
> >>
> >> * Use more common register macros
> >>
> >> * Use bulk clk and reset APIs
> >> ---
> >> drivers/pci/controller/dwc/pcie-designware.h | 1 +
> >> drivers/pci/controller/dwc/pcie-qcom.c | 150 +++++++++++++++++++
> >> 2 files changed, 151 insertions(+)
> >>
> >> diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
> >> index ceb359b6e6a6..346462c74a3e 100644
> >> --- a/drivers/pci/controller/dwc/pcie-designware.h
> >> +++ b/drivers/pci/controller/dwc/pcie-designware.h
> >> @@ -76,6 +76,7 @@
> >>
> >> #define GEN3_RELATED_OFF 0x890
> >> #define GEN3_RELATED_OFF_GEN3_ZRXDC_NONCOMPL BIT(0)
> >> +#define GEN3_RELATED_OFF_RXEQ_RGRDLESS_RXTS BIT(13)
> >> #define GEN3_RELATED_OFF_GEN3_EQ_DISABLE BIT(16)
> >> #define GEN3_RELATED_OFF_RATE_SHADOW_SEL_SHIFT 24
> >> #define GEN3_RELATED_OFF_RATE_SHADOW_SEL_MASK GENMASK(25, 24)
> >> diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
> >> index 8a7a300163e5..93766aee3e7c 100644
> >> --- a/drivers/pci/controller/dwc/pcie-qcom.c
> >> +++ b/drivers/pci/controller/dwc/pcie-qcom.c
> >> @@ -52,6 +52,10 @@
> >> #define PCIE20_PARF_DBI_BASE_ADDR 0x168
> >> #define PCIE20_PARF_SLV_ADDR_SPACE_SIZE 0x16C
> >> #define PCIE20_PARF_MHI_CLOCK_RESET_CTRL 0x174
> >> +#define AHB_CLK_EN BIT(0)
> >> +#define MSTR_AXI_CLK_EN BIT(1)
> >> +#define BYPASS BIT(4)
> >> +
> >> #define PCIE20_PARF_AXI_MSTR_WR_ADDR_HALT 0x178
> >> #define PCIE20_PARF_AXI_MSTR_WR_ADDR_HALT_V2 0x1A8
> >> #define PCIE20_PARF_LTSSM 0x1B0
> >> @@ -94,6 +98,12 @@
> >> #define SLV_ADDR_SPACE_SZ 0x10000000
> >>
> >> #define PCIE20_LNK_CONTROL2_LINK_STATUS2 0xa0
> >> +#define PCIE_CAP_CURR_DEEMPHASIS BIT(16)
> >
> > Isn't this a standard register field?
>
> I don't know. I could not find any reference to this field or the
> registers it's part of.

It is. I found it in the spec. But it's not in pci_reg.h and it is a
read-only status bit (though some in DWC can be written).

> n
> >> +#define SPEED_GEN1 0x1
> >> +#define SPEED_GEN2 0x2
> >> +#define SPEED_GEN3 0x3
> >
> > And these?

#define PCI_EXP_LNKCTL2 48 /* Link Control 2 */
#define PCI_EXP_LNKCTL2_TLS 0x000f
#define PCI_EXP_LNKCTL2_TLS_2_5GT 0x0001 /* Supported Speed 2.5GT/s */
#define PCI_EXP_LNKCTL2_TLS_5_0GT 0x0002 /* Supported Speed 5GT/s */
#define PCI_EXP_LNKCTL2_TLS_8_0GT 0x0003 /* Supported Speed 8GT/s */
#define PCI_EXP_LNKCTL2_TLS_16_0GT 0x0004 /* Supported Speed 16GT/s */
#define PCI_EXP_LNKCTL2_TLS_32_0GT 0x0005 /* Supported Speed 32GT/s */
#define PCI_EXP_LNKCTL2_TLS_64_0GT 0x0006 /* Supported Speed 64GT/s */
#define PCI_EXP_LNKCTL2_ENTER_COMP 0x0010 /* Enter Compliance */
#define PCI_EXP_LNKCTL2_TX_MARGIN 0x0380 /* Transmit Margin */
#define PCI_EXP_LNKCTL2_HASD 0x0020 /* HW Autonomous Speed Disable */
#define PCI_EXP_LNKSTA2 50 /* Link Status 2 */

> >
> > There's already some common DWC code for setting the link speed.
>
> dw_pcie_link_set_max_speed() deals with other registers, as far as I can
> see.

Link Control2 which is what the above function configures appears to
be the same register to me. Your definition is combining 2 registers.

>
> >> +#define AXI_CLK_RATE 200000000
> >> +#define RCHNG_CLK_RATE 100000000
> >>
> >> #define DEVICE_TYPE_RC 0x4
>
> [snip]
>
> >> +static int qcom_pcie_post_init_2_9_0(struct qcom_pcie *pcie)
> >> +{
> >> + struct dw_pcie *pci = pcie->pci;
> >> + u16 offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP);
> >> + u32 val;
> >> + int i;
> >> +
> >> + writel(SLV_ADDR_SPACE_SZ,
> >> + pcie->parf + PCIE20_v3_PARF_SLV_ADDR_SPACE_SIZE);
> >> +
> >> + val = readl(pcie->parf + PCIE20_PARF_PHY_CTRL);
> >> + val &= ~BIT(0);
> >> + writel(val, pcie->parf + PCIE20_PARF_PHY_CTRL);
> >> +
> >> + writel(0, pcie->parf + PCIE20_PARF_DBI_BASE_ADDR);
> >> +
> >> + writel(DEVICE_TYPE_RC, pcie->parf + PCIE20_PARF_DEVICE_TYPE);
> >> + writel(BYPASS | MSTR_AXI_CLK_EN | AHB_CLK_EN,
> >> + pcie->parf + PCIE20_PARF_MHI_CLOCK_RESET_CTRL);
> >> + writel(GEN3_RELATED_OFF_RXEQ_RGRDLESS_RXTS
> >> + | GEN3_RELATED_OFF_GEN3_ZRXDC_NONCOMPL,
> >> + pci->dbi_base + GEN3_RELATED_OFF);
> >> +
> >> + writel(MST_WAKEUP_EN | SLV_WAKEUP_EN | MSTR_ACLK_CGC_DIS
> >> + | SLV_ACLK_CGC_DIS | CORE_CLK_CGC_DIS |
> >> + AUX_PWR_DET | L23_CLK_RMV_DIS | L1_CLK_RMV_DIS,
> >> + pcie->parf + PCIE20_PARF_SYS_CTRL);
> >> +
> >> + writel(0, pcie->parf + PCIE20_PARF_Q2A_FLUSH);
> >> +
> >> + dw_pcie_dbi_ro_wr_en(pci);
> >> + writel(PCIE_CAP_LINK1_VAL, pci->dbi_base + offset + PCI_EXP_SLTCAP);
> >> +
> >> + /* Configure PCIe link capabilities for ASPM */
> >> + val = readl(pci->dbi_base + offset + PCI_EXP_LNKCAP);
> >> + val &= ~PCI_EXP_LNKCAP_ASPMS;
> >> + writel(val, pci->dbi_base + offset + PCI_EXP_LNKCAP);
> >> +
> >> + writel(PCI_EXP_DEVCTL2_COMP_TMOUT_DIS, pci->dbi_base + offset +
> >> + PCI_EXP_DEVCTL2);
> >> +
> >> + writel(PCIE_CAP_CURR_DEEMPHASIS | SPEED_GEN3,
> >> + pci->dbi_base + offset + PCI_EXP_DEVCTL2);
> >
> > Doesn't this overwrite the prior register write?
>
> It does. There are two mistakes here. The writel() above should set
> PCIE20_DEVICE_CONTROL2_STATUS2 (offset 0x98).

No. Did you check what 'offset' is? PCIE20_DEVICE_CONTROL2_STATUS2 is
PCI_EXP_DEVCTL2 plus the status reg. What's wrong is it should be a
16-bit write.

> This writel() should set
> PCIE20_LNK_CONTROL2_LINK_STATUS2 (offset 0xa0). So both are wrong.
>
> >> +
> >> + for (i = 0;i < 256;i++)
> >> + writel(0x0, pcie->parf + PCIE20_PARF_BDF_TO_SID_TABLE_N
> >> + + (4 * i));
> >> +
> >> + return 0;
> >> +}
>
> Thanks,
> baruch
>
> --
> ~. .~ Tk Open Systems
> =}------------------------------------------------ooO--U--Ooo------------{=
> - baruch@tkos.co.il - tel: +972.52.368.4656, http://www.tkos.co.il -