Linux-Kernel Archive: [PATCH v2 22/23] ata: ahci-dwc: Add Baikal-T1 AHCI SATA interface support [PATCH v2 22/23] ata: ahci-dwc: Add Baikal-T1 AHCI SATA interface support From: Serge Semin Date: Tue May 03 2022 - 16:11:32 EST Next message: Serge Semin: "[PATCH v2 23/23] MAINTAINERS: Add maintainers for DWC AHCI SATA driver" Previous message: Serge Semin: "[PATCH v2 18/23] dt-bindings: ata: ahci: Add DWC AHCI SATA controller DT schema" In reply to: Serge Semin: "[PATCH v2 18/23] dt-bindings: ata: ahci: Add DWC AHCI SATA controller DT schema" Next in thread: Serge Semin: "[PATCH v2 23/23] MAINTAINERS: Add maintainers for DWC AHCI SATA driver" Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] It's almost fully compatible DWC AHCI SATA IP-core derivative except the reference clocks source, which need to be very carefully selected. In particular the DWC AHCI SATA PHY can be clocked either from the pads ref_pad_clk_{m,p} or from the internal wires ref_alt_clk_{m,n}. In the later case the clock signal is generated from the Baikal-T1 CCU SATA PLL. The clocks source is selected by means of the ref_use_pad wire connected to the CCU SATA reference clock CSR. In normal situation it would be much more handy to use the internal reference clock source, but alas we haven't managed to make the AHCI controller working well with it so far. So it's preferable to have the controller clocked from the external clock generator and fallback to the internal clock source only as a last resort. Other than that the controller is full compatible with the DWC AHCI SATA IP-core. Signed-off-by: Serge Semin --- Changelog v2: - Rename 'syscon' property to 'baikal,bt1-syscon'. - Change the local objects prefix from 'dwc_ahci_' to 'ahci_dwc_', from 'bt1_ahci_' to 'ahci_bt1_'. (@Damien) --- drivers/ata/Kconfig | 1 + drivers/ata/ahci_dwc.c | 87 ++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 88 insertions(+) diff --git a/drivers/ata/Kconfig b/drivers/ata/Kconfig index 95e0e022b5bb..249717cdc74f 100644 --- a/drivers/ata/Kconfig +++ b/drivers/ata/Kconfig @@ -180,6 +180,7 @@ config AHCI_DWC tristate "Synopsys DWC AHCI SATA support" select SATA_HOST default SATA_AHCI_PLATFORM + select MFD_SYSCON if (MIPS_BAIKAL_T1 || COMPILE_TEST) help This option enables support for the Synopsys DWC AHCI SATA controller implementation. diff --git a/drivers/ata/ahci_dwc.c b/drivers/ata/ahci_dwc.c index f987efa1ad59..d464db20f869 100644 --- a/drivers/ata/ahci_dwc.c +++ b/drivers/ata/ahci_dwc.c @@ -13,10 +13,12 @@ #include #include #include +#include #include #include #include #include +#include #include "ahci.h" @@ -90,6 +92,26 @@ #define AHCI_DWC_PORT_PHYCR 0x74 #define AHCI_DWC_PORT_PHYSR 0x78 +/* Baikal-T1 AHCI SATA specific registers */ +#define AHCI_BT1_HOST_PHYCR AHCI_DWC_HOST_GPCR +#define AHCI_BT1_HOST_MPLM_MASK GENMASK(29, 23) +#define AHCI_BT1_HOST_LOSDT_MASK GENMASK(22, 20) +#define AHCI_BT1_HOST_CRR BIT(19) +#define AHCI_BT1_HOST_CRW BIT(18) +#define AHCI_BT1_HOST_CRCD BIT(17) +#define AHCI_BT1_HOST_CRCA BIT(16) +#define AHCI_BT1_HOST_CRDI_MASK GENMASK(15, 0) + +#define AHCI_BT1_HOST_PHYSR AHCI_DWC_HOST_GPSR +#define AHCI_BT1_HOST_CRA BIT(16) +#define AHCI_BT1_HOST_CRDO_MASK GENMASK(15, 0) + +/* Baikal-T1 CCU registers concerning the AHCI SATA module */ +#define BT1_CCU_SYS_SATA_REF 0x60 +#define BT1_CCU_SYS_SATA_REF_EXT BIT(28) +#define BT1_CCU_SYS_SATA_REF_INV BIT(29) +#define BT1_CCU_SYS_SATA_REF_BUF BIT(30) + struct ahci_dwc_plat_data { unsigned int pflags; unsigned int hflags; @@ -106,6 +128,65 @@ struct ahci_dwc_host_priv { u32 dmacr[AHCI_MAX_PORTS]; }; +static int ahci_bt1_init(struct ahci_host_priv *hpriv) +{ + struct ahci_dwc_host_priv *dpriv = hpriv->plat_data; + struct regmap *sys_regs; + u32 ref_ctl, mask; + + /* APB and application clocks are required */ + if (!ahci_platform_find_clk(hpriv, "pclk") || + !ahci_platform_find_clk(hpriv, "aclk")) { + dev_err(&dpriv->pdev->dev, "No system clocks specified\n"); + return -EINVAL; + } + + /* + * We need to select the PHY reference clock source. The signal + * can be delivered either from the chip pads or from the internal + * PLL. The source is selected by the PHY's ref_use_pad signal + * tied up into one of the CCU SATA ref-ctl register field. + */ + sys_regs = syscon_regmap_lookup_by_phandle(dpriv->pdev->dev.of_node, + "baikal,bt1-syscon"); + if (IS_ERR(sys_regs)) { + dev_err(&dpriv->pdev->dev, "CCU syscon couldn't be found\n"); + return PTR_ERR(sys_regs); + } + + (void)regmap_read(sys_regs, BT1_CCU_SYS_SATA_REF, &ref_ctl); + + /* + * Prefer activating external reference clock if one is supplied. + * If there is no external ref clock, then we have no choice but + * to fall back to the internal signal coming from PLL. Alas + * we haven't managed to make the interface working well when it's + * used so far, but in no alternative let's at least try... + */ + if (ahci_platform_find_clk(hpriv, "ref_ext")) { + ref_ctl |= BT1_CCU_SYS_SATA_REF_EXT; + mask = BT1_CCU_SYS_SATA_REF_EXT; + } else if (ahci_platform_find_clk(hpriv, "ref_int")) { + ref_ctl &= ~BT1_CCU_SYS_SATA_REF_EXT; + ref_ctl |= BT1_CCU_SYS_SATA_REF_INV | BT1_CCU_SYS_SATA_REF_BUF; + mask = BT1_CCU_SYS_SATA_REF_EXT | + BT1_CCU_SYS_SATA_REF_INV | BT1_CCU_SYS_SATA_REF_BUF; + dev_warn(&dpriv->pdev->dev, "Fallback to PLL-based ref clock!\n"); + } else { + dev_err(&dpriv->pdev->dev, "No ref clock specified\n"); + return -EINVAL; + } + + regmap_update_bits(sys_regs, BT1_CCU_SYS_SATA_REF, mask, ref_ctl); + + /* + * Fully reset the SATA AXI and ref clocks domain so to ensure the + * state machine is working from scratch. + */ + ahci_platform_assert_rsts(hpriv); + return ahci_platform_deassert_rsts(hpriv); +} + static struct ahci_host_priv *ahci_dwc_get_resources(struct platform_device *pdev) { struct ahci_dwc_host_priv *dpriv; @@ -415,9 +496,15 @@ struct ahci_dwc_plat_data ahci_dwc_plat = { .pflags = AHCI_PLATFORM_GET_RESETS, }; +struct ahci_dwc_plat_data ahci_bt1_plat = { + .pflags = AHCI_PLATFORM_GET_RESETS | AHCI_PLATFORM_RST_TRIGGER, + .init = ahci_bt1_init, +}; + static const struct of_device_id ahci_dwc_of_match[] = { { .compatible = "snps,dwc-ahci", &ahci_dwc_plat }, { .compatible = "snps,spear-ahci", &ahci_dwc_plat }, + { .compatible = "baikal,bt1-ahci", &ahci_bt1_plat }, {}, }; MODULE_DEVICE_TABLE(of, ahci_dwc_of_match); -- 2.35.1 Next message: Serge Semin: "[PATCH v2 23/23] MAINTAINERS: Add maintainers for DWC AHCI SATA driver" Previous message: Serge Semin: "[PATCH v2 18/23] dt-bindings: ata: ahci: Add DWC AHCI SATA controller DT schema" In reply to: Serge Semin: "[PATCH v2 18/23] dt-bindings: ata: ahci: Add DWC AHCI SATA controller DT schema" Next in thread: Serge Semin: "[PATCH v2 23/23] MAINTAINERS: Add maintainers for DWC AHCI SATA driver" Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]
