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SubjectRe: [PATCH v6 2/5] phy: qcom-qmp: Utilize fully-specified DT registers
On Fri, Dec 7, 2018 at 5:06 AM Evan Green <evgreen@chromium.org> wrote:
>
> Utilize the newly fixed up DT bindings to get the tx2 and rx2 register
> regions for the second lane of dual-lane PHYs. Before this change,
> the driver was simply using lane one's register region and adding
> 0x400, which reached well beyond the DT-specified register
> allocation. This would have been a crash were it not for the page size
> on ARM64. Fix the driver not to rely on the magic of virtual memory by
> using the newly specified DT register regions for tx2 and rx2.
>
> In order to support existing device trees, this change also contains a
> fallback mode for when those new register regions don't exist, which
> reverts to the original behavior of overreaching and prints a complaint.
>
> Signed-off-by: Evan Green <evgreen@chromium.org>
> Reviewed-by: Douglas Anderson <dianders@chromium.org>
> ---
> As Doug mentioned, this should land before the dts patches land, otherwise
> the old driver code will use the tx2 register region as pcs_misc.
>
> Changes in v6: None
> Changes in v5: None
> Changes in v4: None
> Changes in v3: None
> Changes in v2: None
>
> drivers/phy/qualcomm/phy-qcom-qmp.c | 51 +++++++++++++++++++++--------
> 1 file changed, 38 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/phy/qualcomm/phy-qcom-qmp.c b/drivers/phy/qualcomm/phy-qcom-qmp.c
> index 514db7248a5d0..8204d55e2d650 100644
> --- a/drivers/phy/qualcomm/phy-qcom-qmp.c
> +++ b/drivers/phy/qualcomm/phy-qcom-qmp.c
> @@ -72,6 +72,9 @@
>
> #define MAX_PROP_NAME 32
>
> +/* Define the assumed distance between lanes for underspecified device trees. */
> +#define QMP_PHY_LEGACY_LANE_STRIDE 0x400
> +
> struct qmp_phy_init_tbl {
> unsigned int offset;
> unsigned int val;
> @@ -733,9 +736,6 @@ struct qmp_phy_cfg {
> bool has_phy_dp_com_ctrl;
> /* true, if PHY has secondary tx/rx lanes to be configured */
> bool is_dual_lane_phy;
> - /* Register offset of secondary tx/rx lanes for USB DP combo PHY */
> - unsigned int tx_b_lane_offset;
> - unsigned int rx_b_lane_offset;
>
> /* true, if PCS block has no separate SW_RESET register */
> bool no_pcs_sw_reset;
> @@ -748,6 +748,8 @@ struct qmp_phy_cfg {
> * @tx: iomapped memory space for lane's tx
> * @rx: iomapped memory space for lane's rx
> * @pcs: iomapped memory space for lane's pcs
> + * @tx2: iomapped memory space for second lane's tx (in dual lane PHYs)
> + * @rx2: iomapped memory space for second lane's rx (in dual lane PHYs)
> * @pcs_misc: iomapped memory space for lane's pcs_misc
> * @pipe_clk: pipe lock
> * @index: lane index
> @@ -759,6 +761,8 @@ struct qmp_phy {
> void __iomem *tx;
> void __iomem *rx;
> void __iomem *pcs;
> + void __iomem *tx2;
> + void __iomem *rx2;
> void __iomem *pcs_misc;
> struct clk *pipe_clk;
> unsigned int index;
> @@ -975,8 +979,6 @@ static const struct qmp_phy_cfg qmp_v3_usb3phy_cfg = {
>
> .has_phy_dp_com_ctrl = true,
> .is_dual_lane_phy = true,
> - .tx_b_lane_offset = 0x400,
> - .rx_b_lane_offset = 0x400,
> };
>
> static const struct qmp_phy_cfg qmp_v3_usb3_uniphy_cfg = {
> @@ -1031,9 +1033,6 @@ static const struct qmp_phy_cfg sdm845_ufsphy_cfg = {
> .mask_pcs_ready = PCS_READY,
>
> .is_dual_lane_phy = true,
> - .tx_b_lane_offset = 0x400,
> - .rx_b_lane_offset = 0x400,
> -
> .no_pcs_sw_reset = true,
> };
>
> @@ -1238,12 +1237,12 @@ static int qcom_qmp_phy_init(struct phy *phy)
> qcom_qmp_phy_configure(tx, cfg->regs, cfg->tx_tbl, cfg->tx_tbl_num);
> /* Configuration for other LANE for USB-DP combo PHY */
> if (cfg->is_dual_lane_phy)
> - qcom_qmp_phy_configure(tx + cfg->tx_b_lane_offset, cfg->regs,
> + qcom_qmp_phy_configure(qphy->tx2, cfg->regs,
> cfg->tx_tbl, cfg->tx_tbl_num);
>
> qcom_qmp_phy_configure(rx, cfg->regs, cfg->rx_tbl, cfg->rx_tbl_num);
> if (cfg->is_dual_lane_phy)
> - qcom_qmp_phy_configure(rx + cfg->rx_b_lane_offset, cfg->regs,
> + qcom_qmp_phy_configure(qphy->rx2, cfg->regs,
> cfg->rx_tbl, cfg->rx_tbl_num);
>
> qcom_qmp_phy_configure(pcs, cfg->regs, cfg->pcs_tbl, cfg->pcs_tbl_num);
> @@ -1615,8 +1614,9 @@ int qcom_qmp_phy_create(struct device *dev, struct device_node *np, int id)
>
> /*
> * Get memory resources for each phy lane:
> - * Resources are indexed as: tx -> 0; rx -> 1; pcs -> 2; and
> - * pcs_misc (optional) -> 3.
> + * Resources are indexed as: tx -> 0; rx -> 1; pcs -> 2.
> + * For dual lane PHYs: tx2 -> 3, rx2 -> 4, pcs_misc (optional) -> 5
> + * For single lane PHYs: pcs_misc (optional) -> 3.
> */
> qphy->tx = of_iomap(np, 0);
> if (!qphy->tx)
> @@ -1630,7 +1630,32 @@ int qcom_qmp_phy_create(struct device *dev, struct device_node *np, int id)
> if (!qphy->pcs)
> return -ENOMEM;
>
> - qphy->pcs_misc = of_iomap(np, 3);
> + /*
> + * If this is a dual-lane PHY, then there should be registers for the
> + * second lane. Some old device trees did not specify this, so fall
> + * back to old legacy behavior of assuming they can be reached at an
> + * offset from the first lane.
> + */
> + if (qmp->cfg->is_dual_lane_phy) {
> + qphy->tx2 = of_iomap(np, 3);
> + qphy->rx2 = of_iomap(np, 4);
> + if (!qphy->tx2 || !qphy->rx2) {
> + dev_warn(dev,
> + "Underspecified device tree, falling back to legacy register regions\n");
> +
> + /* In the old version, pcs_misc is at index 3. */
> + qphy->pcs_misc = qphy->tx2;
> + qphy->tx2 = qphy->tx + QMP_PHY_LEGACY_LANE_STRIDE;
> + qphy->rx2 = qphy->rx + QMP_PHY_LEGACY_LANE_STRIDE;
> +
> + } else {
> + qphy->pcs_misc = of_iomap(np, 5);
> + }
> +
> + } else {
> + qphy->pcs_misc = of_iomap(np, 3);
> + }
> +
> if (!qphy->pcs_misc)
> dev_vdbg(dev, "PHY pcs_misc-reg not used\n");
>
> --
> 2.18.1
>

Tested on db820c [1]. USB, PCIe come up.
Tested-by: Vivek Gautam <vivek.gautam@codeaurora.org>

[1] https://github.com/vivekgautam1/linux/tree/origin/v4.20-rc5/db820c

BRs

--
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
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