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Message-ID: <67799341-d27f-4a46-9874-0fc12b6e56d4@quicinc.com>
Date: Mon, 8 Apr 2024 14:32:17 -0700
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Subject: Re: [PATCH v7 11/37] pci: pci-sh7751: Add SH7751 PCI driver
Content-Language: en-US
To: Yoshinori Sato <ysato@users.sourceforge.jp>, <linux-sh@vger.kernel.org>
CC: Damien Le Moal <dlemoal@kernel.org>, Niklas Cassel <cassel@kernel.org>,
        Rob Herring <robh@kernel.org>,
        Krzysztof Kozlowski
	<krzysztof.kozlowski+dt@linaro.org>,
        Conor Dooley <conor+dt@kernel.org>,
        Geert Uytterhoeven <geert+renesas@glider.be>,
        Michael Turquette
	<mturquette@baylibre.com>,
        Stephen Boyd <sboyd@kernel.org>, David Airlie
	<airlied@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        Maarten Lankhorst
	<maarten.lankhorst@linux.intel.com>,
        Maxime Ripard <mripard@kernel.org>,
        Thomas Zimmermann <tzimmermann@suse.de>,
        Thomas Gleixner
	<tglx@linutronix.de>,
        Bjorn Helgaas <bhelgaas@google.com>,
        Lorenzo Pieralisi
	<lpieralisi@kernel.org>,
        =?UTF-8?Q?Krzysztof_Wilczy=C5=84ski?=
	<kw@linux.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Jiri Slaby
	<jirislaby@kernel.org>,
        Magnus Damm <magnus.damm@gmail.com>,
        Daniel Lezcano
	<daniel.lezcano@linaro.org>,
        Rich Felker <dalias@libc.org>,
        John Paul Adrian
 Glaubitz <glaubitz@physik.fu-berlin.de>,
        Lee Jones <lee@kernel.org>, Helge
 Deller <deller@gmx.de>,
        Heiko Stuebner <heiko.stuebner@cherry.de>,
        Shawn Guo
	<shawnguo@kernel.org>, Sebastian Reichel <sre@kernel.org>,
        Chris Morgan
	<macromorgan@hotmail.com>,
        Linus Walleij <linus.walleij@linaro.org>,
        Arnd
 Bergmann <arnd@arndb.de>, David Rientjes <rientjes@google.com>,
        Hyeonggon Yoo
	<42.hyeyoo@gmail.com>, Vlastimil Babka <vbabka@suse.cz>,
        Baoquan He
	<bhe@redhat.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Guenter Roeck
	<linux@roeck-us.net>,
        Kefeng Wang <wangkefeng.wang@huawei.com>,
        Stephen
 Rothwell <sfr@canb.auug.org.au>,
        Javier Martinez Canillas
	<javierm@redhat.com>,
        Guo Ren <guoren@kernel.org>, Azeem Shaikh
	<azeemshaikh38@gmail.com>,
        Max Filippov <jcmvbkbc@gmail.com>, Jonathan Corbet
	<corbet@lwn.net>,
        Jacky Huang <ychuang3@nuvoton.com>,
        Herve Codina
	<herve.codina@bootlin.com>,
        Manikanta Guntupalli
	<manikanta.guntupalli@amd.com>,
        Anup Patel <apatel@ventanamicro.com>,
        Biju
 Das <biju.das.jz@bp.renesas.com>,
        =?UTF-8?Q?Uwe_Kleine-K=C3=B6nig?=
	<u.kleine-koenig@pengutronix.de>,
        Sam Ravnborg <sam@ravnborg.org>, Sergey
 Shtylyov <s.shtylyov@omp.ru>,
        Laurent Pinchart
	<laurent.pinchart+renesas@ideasonboard.com>,
        <linux-ide@vger.kernel.org>, <devicetree@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, <linux-renesas-soc@vger.kernel.org>,
        <linux-clk@vger.kernel.org>, <dri-devel@lists.freedesktop.org>,
        <linux-pci@vger.kernel.org>, <linux-serial@vger.kernel.org>,
        <linux-fbdev@vger.kernel.org>
References: <cover.1712205900.git.ysato@users.sourceforge.jp>
 <8c44b3e28da65cf47ff6bd53cf8e9cf30f2b4cb0.1712205900.git.ysato@users.sourceforge.jp>
From: Mayank Rana <quic_mrana@quicinc.com>
In-Reply-To: <8c44b3e28da65cf47ff6bd53cf8e9cf30f2b4cb0.1712205900.git.ysato@users.sourceforge.jp>
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Content-Transfer-Encoding: 7bit

Hi,

On 4/3/2024 9:59 PM, Yoshinori Sato wrote:
> Renesas SH7751 CPU Internal PCI Controller driver.
> 
> Signed-off-by: Yoshinori Sato <ysato@users.sourceforge.jp>
> ---
>   drivers/pci/controller/Kconfig      |   9 +
>   drivers/pci/controller/Makefile     |   1 +
>   drivers/pci/controller/pci-sh7751.c | 342 ++++++++++++++++++++++++++++
>   3 files changed, 352 insertions(+)
>   create mode 100644 drivers/pci/controller/pci-sh7751.c
> 
> diff --git a/drivers/pci/controller/Kconfig b/drivers/pci/controller/Kconfig
> index e534c02ee34f..a2fd917a2e03 100644
> --- a/drivers/pci/controller/Kconfig
> +++ b/drivers/pci/controller/Kconfig
> @@ -353,6 +353,15 @@ config PCIE_XILINX_CPM
>   	  Say 'Y' here if you want kernel support for the
>   	  Xilinx Versal CPM host bridge.
>   
> +config PCI_SH7751
> +	bool "Renesas SH7751 PCI controller"
> +	depends on OF
> +	depends on CPU_SUBTYPE_SH7751 || CPU_SUBTYPE_SH7751R || COMPILE_TEST
> +	select PCI_HOST_COMMON
> +	help
> +	  Say 'Y' here if you want kernel to support the Renesas SH7751 PCI
> +	  Host Bridge driver.
> +
>   source "drivers/pci/controller/cadence/Kconfig"
>   source "drivers/pci/controller/dwc/Kconfig"
>   source "drivers/pci/controller/mobiveil/Kconfig"
> diff --git a/drivers/pci/controller/Makefile b/drivers/pci/controller/Makefile
> index f2b19e6174af..aa97e5d74e58 100644
> --- a/drivers/pci/controller/Makefile
> +++ b/drivers/pci/controller/Makefile
> @@ -40,6 +40,7 @@ obj-$(CONFIG_PCI_LOONGSON) += pci-loongson.o
>   obj-$(CONFIG_PCIE_HISI_ERR) += pcie-hisi-error.o
>   obj-$(CONFIG_PCIE_APPLE) += pcie-apple.o
>   obj-$(CONFIG_PCIE_MT7621) += pcie-mt7621.o
> +obj-$(CONFIG_PCI_SH7751) += pci-sh7751.o
>   
>   # pcie-hisi.o quirks are needed even without CONFIG_PCIE_DW
>   obj-y				+= dwc/
> diff --git a/drivers/pci/controller/pci-sh7751.c b/drivers/pci/controller/pci-sh7751.c
> new file mode 100644
> index 000000000000..a5340689f737
> --- /dev/null
> +++ b/drivers/pci/controller/pci-sh7751.c
> @@ -0,0 +1,342 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * SH7751 PCI driver
> + * Copyright (C) 2023 Yoshinori Sato
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/of_address.h>
> +#include <linux/of_pci.h>
> +#include <linux/of_platform.h>
> +#include <linux/pci-ecam.h>
> +#include <linux/platform_device.h>
> +#include <linux/io.h>
> +#include <linux/pci.h>
> +#include <linux/dma-direct.h>
> +#include <asm/addrspace.h>
can you consider to rearranging headers into alphabetically sorted order ?
> +
> +/* PCICR and PCICLKCR write enable magic key */
> +#define PCIC_WE_KEY		(0xa5 << 24)
> +
> +/* PCIC registers */
> +/* 0x0000 - 0x00ff mapped to PCI device configuration space */
> +#define PCIC_PCICR		0x100	/* PCI Control Register */
> +#define PCIC_PCICR_TRSB		BIT(9)	/* Target Read Single */
> +#define PCIC_PCICR_BSWP		BIT(8)	/* Target Byte Swap */
> +#define PCIC_PCICR_PLUP		BIT(7)	/* Enable PCI Pullup */
> +#define PCIC_PCICR_ARBM		BIT(6)	/* PCI Arbitration Mode */
> +#define PCIC_PCICR_MD10		BIT(5)	/* MD10 status */
> +#define PCIC_PCICR_MD9		BIT(4)	/* MD9 status */
> +#define PCIC_PCICR_SERR		BIT(3)	/* SERR output assert */
> +#define PCIC_PCICR_INTA		BIT(2)	/* INTA output assert */
> +#define PCIC_PCICR_PRST		BIT(1)	/* PCI Reset Assert */
> +#define PCIC_PCICR_CFIN		BIT(0)	/* Central Fun. Init Done */
> +
> +#define PCIC_PCILSR0		0x104	/* PCI Local Space Register0 */
> +#define PCIC_PCILSR1		0x108	/* PCI Local Space Register1 */
> +#define PCIC_PCILAR0		0x10c	/* PCI Local Addr Register1 */
> +#define PCIC_PCILAR1		0x110	/* PCI Local Addr Register1 */
> +#define PCIC_PCIINT		0x114	/* PCI Interrupt Register */
> +#define PCIC_PCIINTM		0x118	/* PCI Interrupt Mask */
> +#define PCIC_PCIALR		0x11c	/* Error Address Register */
> +#define PCIC_PCICLR		0x120	/* Error Command/Data */
> +#define PCIC_PCIAINT		0x130	/* Arbiter Interrupt Register */
> +#define PCIC_PCIAINTM		0x134	/* Arbiter Int. Mask Register */
> +#define PCIC_PCIBMLR		0x138	/* Error Bus Master Register */
> +#define PCIC_PCIDMABT		0x140	/* DMA Transfer Arb. Register */
> +#define PCIC_PCIPAR		0x1c0	/* PIO Address Register */
> +#define PCIC_PCIMBR		0x1c4	/* Memory Base Address */
> +#define PCIC_PCIIOBR		0x1c8	/* I/O Base Address Register */
> +
> +#define PCIC_PCIPINT		0x1cc	/* Power Mgmnt Int. Register */
> +#define PCIC_PCIPINT_D3		BIT(1)	/* D3 Pwr Mgmt. Interrupt */
> +#define PCIC_PCIPINT_D0		BIT(0)	/* D0 Pwr Mgmt. Interrupt */
> +
> +#define PCIC_PCIPINTM		0x1d0	/* Power Mgmnt Mask Register */
> +#define PCIC_PCICLKR		0x1d4	/* Clock Ctrl. Register */
> +#define PCIC_PCIBCR1		0x1e0	/* Memory BCR1 Register */
> +#define PCIC_PCIBCR2		0x1e4	/* Memory BCR2 Register */
> +#define PCIC_PCIWCR1		0x1e8	/* Wait Control 1 Register */
> +#define PCIC_PCIWCR2		0x1ec	/* Wait Control 2 Register */
> +#define PCIC_PCIWCR3		0x1f0	/* Wait Control 3 Register */
> +#define PCIC_PCIMCR		0x1f4	/* Memory Control Register */
> +#define PCIC_PCIBCR3		0x1f8	/* Memory BCR3 Register */
> +#define PCIC_PCIPDR		0x220	/* Port IO Data Register */
> +
> +/* PCI IDs */
> +/* Hitachi is the company that led to Renesas. */
> +/* The SH7751 was designed by Hitachi, so it has a Hitachi ID. */
multi-line comments way ?
> +#define PCI_VENDOR_ID_HITACHI	0x1054
> +#define PCI_DEVICE_ID_SH7751	0x3505
> +#define PCI_DEVICE_ID_SH7751R	0x350e
> +
> +/* BSC registers */
> +/* Copy BSC setting to PCI BSC */
> +#define BSC_BCR1		0x0000
> +#define BSC_BCR1_SLAVE		BIT(30)
> +#define BSC_BCR1_BRQEN		BIT(19)
> +#define BSC_BCR2		0x0004
> +#define BSC_BCR3		0x0050
> +#define BSC_WCR1		0x0008
> +#define BSC_WCR2		0x000c
> +#define BSC_WCR3		0x0010
> +#define BSC_MCR			0x0014
> +#define BSC_MCR_MRSET		BIT(30)
> +#define BSC_MCR_RFSH		BIT(2)
> +
> +/* PCIC access wrapper */
> +#define pcic_writel(val, base, reg)	writel(val, base + (reg))
> +#define pcic_readl(base, reg)		readl(base + (reg))
Do you really needed these new macros ? Is it for better readability ?
> +/*
> + * We need to avoid collisions with `mirrored' VGA ports
> + * and other strange ISA hardware, so we always want the
> + * addresses to be allocated in the 0x000-0x0ff region
> + * modulo 0x400.
> + */
> +#define IO_REGION_BASE 0x1000
> +resource_size_t pcibios_align_resource(void *data, const struct resource *res,
> +				resource_size_t size, resource_size_t align)
> +{
> +	resource_size_t start = res->start;
> +
> +	if (res->flags & IORESOURCE_IO) {
> +		if (start < PCIBIOS_MIN_IO + IO_REGION_BASE)
> +			start = PCIBIOS_MIN_IO + IO_REGION_BASE;
> +
> +		/*
> +		 * Put everything into 0x00-0xff region modulo 0x400.
> +		 */
single line comment would work. no ?
> +		if (start & 0x300)
> +			start = (start + 0x3ff) & ~0x3ff;
> +	}
> +
> +	return start;
> +}
> +
> +static int setup_pci_bsc(struct device *dev, void __iomem *pcic,
> +			 void __iomem *bsc, unsigned int area, bool bcr3)
> +{
> +	u32 word;
> +
> +	word = __raw_readl(bsc + BSC_BCR1);
> +	/* check BCR for SDRAM in area */
> +	if (((word >> area) & 1) == 0) {
> +		dev_err(dev, "Area %u is not configured for SDRAM. BCR1=0x%x\n",
> +			area, word);
> +		return -EINVAL;
> +	}
> +	word |= BSC_BCR1_SLAVE;		/* PCIC BSC is slave only */
> +	pcic_writel(word, pcic, PCIC_PCIBCR1);
> +
> +	word = __raw_readw(bsc + BSC_BCR2);
> +	/* check BCR2 for 32bit SDRAM interface*/
> +	if (((word >> (area << 1)) & 0x3) != 0x3) {
> +		dev_err(dev, "Area %u is not 32 bit SDRAM. BCR2=0x%x\n",
> +			area, word);
> +		return -EINVAL;
> +	}
> +	pcic_writel(word, pcic, PCIC_PCIBCR2);
> +
> +	if (bcr3) {
> +		/* BCR3 have only SH7751R */
> +		word = __raw_readw(bsc + BSC_BCR3);
> +		pcic_writel(word, pcic, PCIC_PCIBCR3);
> +	}
> +
> +	/* configure the wait control registers */
> +	word = __raw_readl(bsc + BSC_WCR1);
> +	pcic_writel(word, pcic, PCIC_PCIWCR1);
> +	word = __raw_readl(bsc + BSC_WCR2);
> +	pcic_writel(word, pcic, PCIC_PCIWCR2);
> +	word = __raw_readl(bsc + BSC_WCR3);
> +	pcic_writel(word, pcic, PCIC_PCIWCR3);
> +	word = __raw_readl(bsc + BSC_MCR);
> +	/* Clear MRSET and RFSH bit */
> +	word &= ~(BSC_MCR_MRSET | BSC_MCR_RFSH);
> +	pcic_writel(word, pcic, PCIC_PCIMCR);
> +
> +	return 0;
> +}
> +
> +#define NUM_AREA 7
> +static int set_pci_ranges(struct device *dev,
> +			  void __iomem *pcic, void __iomem *bsc, bool bcr3)
> +{
> +	struct resource_entry *dma, *tmp;
> +	struct pci_host_bridge *bridge;
> +	u32 bsc_done[NUM_AREA];
> +	unsigned int la;
> +
> +	bridge = dev_get_drvdata(dev);
> +	pcic_writel(0, pcic, PCIC_PCILAR0);
> +	pcic_writel(0, pcic, PCIC_PCILAR1);
> +	la = 0;
> +	memset(&bsc_done, 0, sizeof(bsc_done));
> +	resource_list_for_each_entry_safe(dma, tmp, &bridge->dma_ranges) {
> +		struct resource *res = dma->res;
> +		unsigned int area;
> +		u32 word;
> +
> +		switch (resource_type(res)) {
> +		case IORESOURCE_IO:
> +			/* BAR0 is I/O space */
> +			word = res->start | 1;
> +			pcic_writel(word, pcic, PCI_BASE_ADDRESS_0);
> +			word = pcic_readl(pcic, PCI_COMMAND);
> +			word |= PCI_COMMAND_IO;
> +			pcic_writel(word, pcic, PCI_COMMAND);
> +			break;
> +		case IORESOURCE_MEM:
> +			if (la > 4) {
> +				dev_err(dev, "Invalid range definition.\n");
> +				return -EINVAL;
> +			}
> +			area = (res->start >> 26) & 0x07;
> +			word = res->end - res->start;
> +			if (area >= NUM_AREA) {
> +				/* Area 7 is reserved. */
> +				dev_info(dev, "Invalid local address 0x%08x. Ignore it.\n",
> +					 res->start);
> +				break;
> +			}
> +			pcic_writel(res->start, pcic, PCI_BASE_ADDRESS_1 + la);
> +			/* if dummy entry, skip BSC setup */
> +			if (word < 4)
> +				break;
> +			/* BAR1 is local area 0, BAR2 is local area 1 */
> +			pcic_writel(word, pcic, PCIC_PCILSR0 + la);
> +			word = P2SEGADDR(res->start);
> +			pcic_writel(word, pcic, PCIC_PCILAR0 + la);
> +			la += 4;
> +			if (!bsc_done[area]) {
> +				/* check BCR for SDRAM in specified area. And setup PCI BSC. */
> +				if (setup_pci_bsc(dev, pcic, bsc, area, bcr3))
> +					return -EINVAL;
> +				bsc_done[area] = 1;
> +			}
> +			break;
> +		}
> +	}
> +	return 0;
> +}
> +
> +static int sh7751_pci_probe(struct platform_device *pdev)
> +{
> +	struct resource *res, *bscres;
> +	void __iomem *pcic;
> +	void __iomem *bsc;
> +	u16 vid, did;
> +	u32 word;
> +	int ret;
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	if (IS_ERR(res))
> +		return PTR_ERR(res);
> +	pcic = ioremap(res->start, res->end - res->start + 1);
Can you consider using devm_platform_ioremap_resource() API ?
> +	bscres = platform_get_resource(pdev, IORESOURCE_MEM, 1);
> +	bsc = devm_ioremap_resource(&pdev->dev, bscres);
> +	if (IS_ERR(bsc))
> +		return PTR_ERR(bsc);
Same as above.
> +	/* check for SH7751/SH7751R hardware */
> +	word = pcic_readl(pcic, PCI_VENDOR_ID);
> +	vid = word & 0xffff;
> +	did = word >> 16;
> +	if ((vid != PCI_VENDOR_ID_HITACHI) ||
> +	    ((did != PCI_DEVICE_ID_SH7751) &&
> +	     (did != PCI_DEVICE_ID_SH7751R))) {
> +		dev_err(&pdev->dev, "This is not an SH7751(R)\n");
error handling missing iounmap(pcic)
> +		return -ENODEV;
> +	}
> +	dev_info(&pdev->dev, "PCI core found at %pR\n", res);
> +
> +	/* Set the BCR's to enable PCI access */
> +	word = __raw_readl(bsc + BSC_BCR1);
> +	word |= BSC_BCR1_BRQEN;
> +	__raw_writel(word, bsc + BSC_BCR1);
> +
> +	/* Turn the clocks back on (not done in reset)*/
> +	pcic_writel(PCIC_WE_KEY | 0, pcic, PCIC_PCICLKR);
> +	/* Clear Powerdown IRQ's (not done in reset) */
> +	word = PCIC_PCIPINT_D3 | PCIC_PCIPINT_D0;
> +	pcic_writel(word, pcic, PCIC_PCIPINT);
> +
> +	/* set the command/status */
> +	word = PCI_COMMAND_MEMORY | PCI_COMMAND_MASTER |
> +		PCI_COMMAND_PARITY | PCI_COMMAND_WAIT;
> +	pcic_writel(word, pcic, PCI_COMMAND);
> +
> +	/* define this host as the host bridge */
> +	word = PCI_BASE_CLASS_BRIDGE << 24;
> +	pcic_writel(word, pcic, PCI_CLASS_REVISION);
> +
> +	ret = pci_host_common_probe(pdev);
> +	if (ret) {
> +		dev_err(&pdev->dev, "Initialize failed (%d)\n", ret);
> +		return ret;
> +	}
> +
> +	/* Set IO and Mem windows to local address */
> +	if (set_pci_ranges(&pdev->dev, pcic, bsc,
> +			   did == PCI_DEVICE_ID_SH7751R))
> +		return -EINVAL;
error handling to call pci_host_common_remove() ?
> +	pcic_writel(0, pcic, PCIC_PCIIOBR);
> +
> +	if (of_property_read_bool(pdev->dev.of_node, "renesas,bus-arbit-round-robin"))
> +		word |= BIT(0);
> +	else
> +		word = 0;
> +	pcic_writel(word, pcic, PCIC_PCIDMABT);
> +
> +	/* SH7751 init done, set central function init complete */
> +	/* use round robin mode to stop a device starving/overrunning */
multi-line comment ?
> +	word = PCIC_PCICR_CFIN | PCIC_PCICR_ARBM;
> +	pcic_writel(PCIC_WE_KEY | word, pcic, PCIC_PCICR);
> +
> +	return 0;
> +}
> +
> +/*
> + * Direct access to PCI hardware...
> + */
> +#define CONFIG_CMD(bus, devfn, where) \
> +	(0x80000000 | (bus->number << 16) | (devfn << 8) | (where & ~3))
> +
> +static void __iomem *sh4_pci_map_bus(struct pci_bus *bus,
> +				     unsigned int devfn, int where)
> +{
> +	struct pci_config_window *cfg = bus->sysdata;
> +	void __iomem *pcic = (void __iomem *)cfg->res.start;
> +
> +	pcic_writel(CONFIG_CMD(bus, devfn, where), pcic, PCIC_PCIPAR);
> +	return pcic + PCIC_PCIPDR;
> +}
> +
> +static const struct pci_ecam_ops pci_sh7751_bus_ops = {
> +	.pci_ops	= {
> +		.map_bus = sh4_pci_map_bus,
> +		.read    = pci_generic_config_read32,
> +		.write   = pci_generic_config_write32,
> +	}
> +};
> +
> +static const struct of_device_id sh7751_pci_of_match[] = {
> +	{ .compatible = "renesas,sh7751-pci",
> +	  .data = &pci_sh7751_bus_ops },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, sh7751_pci_of_match);
> +
> +static struct platform_driver sh7751_pci_driver = {
> +	.driver = {
> +		.name = "sh7751-pci",
> +		.of_match_table = sh7751_pci_of_match,
> +	},
> +	.probe = sh7751_pci_probe,
> +};
> +module_platform_driver(sh7751_pci_driver);
> +
> +MODULE_DESCRIPTION("SH7751 PCI driver");