Re: [PATCH v8 4/5] PCI: rcar-gen4: Add support for r8a779g0

[Manivannan Sadhasivam <mani@kernel.org>]

On Mon, May 20, 2024 at 04:42:59PM +0900, Yoshihiro Shimoda wrote:
> Add support for r8a779g0 (R-Car V4H).
> 
> This driver previously supported r8a779f0 (R-Car S4-8). PCIe features
> of both r8a779f0 and r8a779g0 are almost all the same. For example:
>  - PCI Express Base Specification Revision 4.0
>  - Root complex mode and endpoint mode are supported
> However, r8a779g0 requires specific firmware downloading, to
> initialize the PHY. Otherwise, the PCIe controller cannot work.
> 
> The attached firmware file "104_PCIe_fw_addr_data_ver1.05.txt" in
> the manual is a text file. But, Renesas is not able to distribute
> the firmware freely. So, we require converting the text file
> to a binary before the driver runs by using the following script:
> 
>  $ awk '/^\s*0x[0-9A-Fa-f]{4}\s+0x[0-9A-Fa-f]{4}/ \
>    { print substr($2,5,2) substr($2,3,2) }' \
>    104_PCIe_fw_addr_data_ver1.05.txt | xxd -p -r > \
>    rcar_gen4_pcie.bin
>  $ sha1sum rcar_gen4_pcie.bin
>    1d0bd4b189b4eb009f5d564b1f93a79112994945  rcar_gen4_pcie.bin
> 
> Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
> ---
>  drivers/pci/controller/dwc/pcie-rcar-gen4.c | 194 +++++++++++++++++++-
>  1 file changed, 193 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-rcar-gen4.c b/drivers/pci/controller/dwc/pcie-rcar-gen4.c
> index bcbf0a52890d..f766a9739e15 100644
> --- a/drivers/pci/controller/dwc/pcie-rcar-gen4.c
> +++ b/drivers/pci/controller/dwc/pcie-rcar-gen4.c
> @@ -5,8 +5,10 @@
>   */
>  
>  #include <linux/delay.h>
> +#include <linux/firmware.h>
>  #include <linux/interrupt.h>
>  #include <linux/io.h>
> +#include <linux/iopoll.h>
>  #include <linux/module.h>
>  #include <linux/of.h>
>  #include <linux/pci.h>
> @@ -20,9 +22,10 @@
>  /* Renesas-specific */
>  /* PCIe Mode Setting Register 0 */
>  #define PCIEMSR0		0x0000
> -#define BIFUR_MOD_SET_ON	BIT(0)
> +#define APP_SRIS_MODE		BIT(6)
>  #define DEVICE_TYPE_EP		0
>  #define DEVICE_TYPE_RC		BIT(4)
> +#define BIFUR_MOD_SET_ON	BIT(0)
>  
>  /* PCIe Interrupt Status 0 */
>  #define PCIEINTSTS0		0x0084
> @@ -37,19 +40,36 @@
>  #define PCIEDMAINTSTSEN		0x0314
>  #define PCIEDMAINTSTSEN_INIT	GENMASK(15, 0)
>  
> +/* Port Logic Registers 89 */
> +#define PRTLGC89		0x0b70
> +
> +/* Port Logic Registers 90 */
> +#define PRTLGC90		0x0b74
> +
>  /* PCIe Reset Control Register 1 */
>  #define PCIERSTCTRL1		0x0014
>  #define APP_HOLD_PHY_RST	BIT(16)
>  #define APP_LTSSM_ENABLE	BIT(0)
>  
> +/* PCIe Power Management Control */
> +#define PCIEPWRMNGCTRL		0x0070
> +#define APP_CLK_REQ_N		BIT(11)
> +#define APP_CLK_PM_EN		BIT(10)
> +
>  #define RCAR_NUM_SPEED_CHANGE_RETRIES	10
>  #define RCAR_MAX_LINK_SPEED		4
>  
>  #define RCAR_GEN4_PCIE_EP_FUNC_DBI_OFFSET	0x1000
>  #define RCAR_GEN4_PCIE_EP_FUNC_DBI2_OFFSET	0x800
>  
> +/* About the firmware, please refer to the commit log */

Which commit log? This is no useful info to the developers. Please add the
actual information about the firmware here (whatever you mentioned in the commit
message).

> +#define RCAR_GEN4_PCIE_FIRMWARE_NAME		"rcar_gen4_pcie.bin"
> +#define RCAR_GEN4_PCIE_FIRMWARE_BASE_ADDR	0xc000
> +MODULE_FIRMWARE(RCAR_GEN4_PCIE_FIRMWARE_NAME);
> +
>  struct rcar_gen4_pcie;
>  struct rcar_gen4_pcie_drvdata {
> +	void (*additional_common_init)(struct rcar_gen4_pcie *rcar);
>  	int (*ltssm_control)(struct rcar_gen4_pcie *rcar, bool enable);
>  	enum dw_pcie_device_mode mode;
>  };
> @@ -57,6 +77,7 @@ struct rcar_gen4_pcie_drvdata {
>  struct rcar_gen4_pcie {
>  	struct dw_pcie dw;
>  	void __iomem *base;
> +	void __iomem *phy_base;
>  	struct platform_device *pdev;
>  	const struct rcar_gen4_pcie_drvdata *drvdata;
>  };
> @@ -180,6 +201,9 @@ static int rcar_gen4_pcie_common_init(struct rcar_gen4_pcie *rcar)
>  	if (ret)
>  		goto err_unprepare;
>  
> +	if (rcar->drvdata->additional_common_init)
> +		rcar->drvdata->additional_common_init(rcar);
> +
>  	return 0;
>  
>  err_unprepare:
> @@ -221,6 +245,10 @@ static void rcar_gen4_pcie_unprepare(struct rcar_gen4_pcie *rcar)
>  
>  static int rcar_gen4_pcie_get_resources(struct rcar_gen4_pcie *rcar)
>  {
> +	rcar->phy_base = devm_platform_ioremap_resource_byname(rcar->pdev, "phy");
> +	if (IS_ERR(rcar->phy_base))
> +		return PTR_ERR(rcar->phy_base);
> +
>  	/* Renesas-specific registers */
>  	rcar->base = devm_platform_ioremap_resource_byname(rcar->pdev, "app");
>  
> @@ -514,6 +542,166 @@ static int r8a779f0_pcie_ltssm_control(struct rcar_gen4_pcie *rcar, bool enable)
>  	return 0;
>  }
>  
> +static void rcar_gen4_pcie_additional_common_init(struct rcar_gen4_pcie *rcar)
> +{
> +	struct dw_pcie *dw = &rcar->dw;
> +	u32 val;
> +
> +	/*
> +	 * The SoC manual said the register setting is required. Otherwise,
> +	 * linkup failed.

This also can be dropped.

> +	 */
> +	val = dw_pcie_readl_dbi(dw, PCIE_PORT_LANE_SKEW);
> +	val &= ~PORT_LANE_SKEW_INSERT_MASK;
> +	if (dw->num_lanes < 4)
> +		val |= BIT(6);
> +	dw_pcie_writel_dbi(dw, PCIE_PORT_LANE_SKEW, val);
> +
> +	val = readl(rcar->base + PCIEPWRMNGCTRL);
> +	val |= APP_CLK_REQ_N | APP_CLK_PM_EN;
> +	writel(val, rcar->base + PCIEPWRMNGCTRL);
> +}
> +
> +static void rcar_gen4_pcie_phy_reg_update_bits(struct rcar_gen4_pcie *rcar,
> +					       u32 offset, u32 mask, u32 val)
> +{
> +	u32 tmp;
> +
> +	tmp = readl(rcar->phy_base + offset);
> +	tmp &= ~mask;
> +	tmp |= val;

Use FIELD_* macros to avoid using the shift value.

> +	writel(tmp, rcar->phy_base + offset);
> +}
> +
> +static int rcar_gen4_pcie_reg_test_bit(struct rcar_gen4_pcie *rcar,
> +				       u32 offset, u32 mask)
> +{
> +	struct dw_pcie *dw = &rcar->dw;
> +
> +	if (dw_pcie_readl_dbi(dw, offset) & mask)
> +		return -EAGAIN;

Here a comment like below could be added at the top of the function
definition.

	/*
	 * SoC reference manual suggests checking port logic register bits
	 * during firmware write. If read returns non-zero value, then this
	 * function returns -EAGAIN indicating that the write needs to be done
	 * again. If read returns zero, then return 0 to indicate success.
	 */

> +
> +	return 0;
> +}
> +
> +static int rcar_gen4_pcie_download_phy_firmware(struct rcar_gen4_pcie *rcar)
> +{
> +	/* The check_addr values are magical numbers in the datasheet */
> +	const u32 check_addr[] = { 0x00101018, 0x00101118, 0x00101021, 0x00101121};
> +	struct dw_pcie *dw = &rcar->dw;
> +	const struct firmware *fw;
> +	unsigned int i, timeout;
> +	u32 data;
> +	int ret;
> +
> +	ret = request_firmware(&fw, RCAR_GEN4_PCIE_FIRMWARE_NAME, dw->dev);
> +	if (ret) {
> +		dev_err(dw->dev, "%s: Requesting firmware failed (%s)\n",
> +			__func__, RCAR_GEN4_PCIE_FIRMWARE_NAME);

		dev_err(dw->dev, "Failed to load firmware (%s): %d",
			RCAR_GEN4_PCIE_FIRMWARE_NAME, ret);

> +		return ret;
> +	}
> +
> +	for (i = 0; i < (fw->size / 2); i++) {
> +		data = fw->data[(i * 2) + 1] << 8 | fw->data[i * 2];
> +		timeout = 100;
> +		do {
> +			dw_pcie_writel_dbi(dw, PRTLGC89, RCAR_GEN4_PCIE_FIRMWARE_BASE_ADDR + i);
> +			dw_pcie_writel_dbi(dw, PRTLGC90, data);
> +			if (rcar_gen4_pcie_reg_test_bit(rcar, PRTLGC89, BIT(30)) >= 0)

Can the return value > 0?

> +				break;
> +			if (!(--timeout)) {
> +				ret = -ETIMEDOUT;
> +				goto exit;
> +			}
> +			usleep_range(100, 200);
> +		} while (1);
> +	}
> +
> +	rcar_gen4_pcie_phy_reg_update_bits(rcar, 0x0f8, BIT(17), BIT(17));
> +
> +	for (i = 0; i < ARRAY_SIZE(check_addr); i++) {
> +		timeout = 100;
> +		do {
> +			dw_pcie_writel_dbi(dw, PRTLGC89, check_addr[i]);
> +			ret = rcar_gen4_pcie_reg_test_bit(rcar, PRTLGC89, BIT(30));
> +			ret |= rcar_gen4_pcie_reg_test_bit(rcar, PRTLGC90, BIT(0));
> +			if (ret >= 0)

Same as above.

> +				break;
> +			if (!(--timeout)) {
> +				ret = -ETIMEDOUT;
> +				goto exit;
> +			}
> +			usleep_range(100, 200);
> +		} while (1);
> +	}
> +
> +	ret = 0;

At this point, ret should be 0, right?

> +exit:
> +	release_firmware(fw);
> +
> +	return ret;
> +}
> +
> +static int rcar_gen4_pcie_ltssm_control(struct rcar_gen4_pcie *rcar, bool enable)
> +{
> +	struct dw_pcie *dw = &rcar->dw;
> +	u32 val;
> +	int ret;
> +
> +	if (!enable) {
> +		val = readl(rcar->base + PCIERSTCTRL1);

There is no need to use 'readl/writel' here (which has the barrier), but since
this driver is already using them, I'm not asking to change it now. But please
consider switching to _relaxed variants in a separate series.

> +		val &= ~APP_LTSSM_ENABLE;
> +		writel(val, rcar->base + PCIERSTCTRL1);
> +
> +		return 0;
> +	}
> +
> +	val = dw_pcie_readl_dbi(dw, PCIE_PORT_FORCE);
> +	val |= PORT_FORCE_DO_DESKEW_FOR_SRIS;
> +	dw_pcie_writel_dbi(dw, PCIE_PORT_FORCE, val);
> +
> +	val = readl(rcar->base + PCIEMSR0);
> +	val |= APP_SRIS_MODE;
> +	writel(val, rcar->base + PCIEMSR0);
> +
> +	/*
> +	 * The R-Car Gen4 documents don't describe the PHY registers' name.

Gen4 datasheet? or reference manual?

- Mani

-- 
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