Subject: Re: [PATCH v2 3/4] MIPS: SGI-IP27: fix readb/writeb addressing

From: Alexandre Belloni <[email-masked]>
Date: Thu, 11 Apr 2019 23:17:27 +0200

On 09/04/2019 17:46:07+0200, Thomas Bogendoerfer wrote:
> Our chosen byte swapping, which is what firmware already uses, is to
> do readl/writel by normal lw/sw intructions (data invariance). This
> also means we need to mangle addresses for u8 and u16 accesses. The
> mangling for 16bit has been done aready, but 8bit one was missing.
> Correcting this causes different addresses for accesses to the
> SuperIO and local bus of the IOC3 chip. This is fixed by changing
> byte order in ioc3 and m48rtc_rtc structs.
> 
> Signed-off-by: Thomas Bogendoerfer <[email-masked]>

Considering this is probably the only platform to have that RTC and that
is probably not worth having a better fix for a platform this old:

Acked-by: Alexandre Belloni <[email-masked]>

> ---
>  arch/mips/include/asm/mach-ip27/mangle-port.h |   2 +-
>  arch/mips/include/asm/sn/ioc3.h               | 198 +++++++++++++-------------
>  arch/mips/sgi-ip27/ip27-console.c             |   5 +-
>  drivers/rtc/rtc-m48t35.c                      |  11 ++
>  drivers/tty/serial/8250/8250_ioc3.c           |   4 +-
>  5 files changed, 114 insertions(+), 106 deletions(-)
> 
> diff --git a/arch/mips/include/asm/mach-ip27/mangle-port.h b/arch/mips/include/asm/mach-ip27/mangle-port.h
> index f6e4912ea062..7771ae0f3971 100644
> --- a/arch/mips/include/asm/mach-ip27/mangle-port.h
> +++ b/arch/mips/include/asm/mach-ip27/mangle-port.h
> @@ -8,7 +8,7 @@
>  #ifndef __ASM_MACH_IP27_MANGLE_PORT_H
>  #define __ASM_MACH_IP27_MANGLE_PORT_H
>  
> -#define __swizzle_addr_b(port)	(port)
> +#define __swizzle_addr_b(port)	((port) ^ 3)
>  #define __swizzle_addr_w(port)	((port) ^ 2)
>  #define __swizzle_addr_l(port)	(port)
>  #define __swizzle_addr_q(port)	(port)
> diff --git a/arch/mips/include/asm/sn/ioc3.h b/arch/mips/include/asm/sn/ioc3.h
> index 69069f420930..059885d736de 100644
> --- a/arch/mips/include/asm/sn/ioc3.h
> +++ b/arch/mips/include/asm/sn/ioc3.h
> @@ -10,35 +10,35 @@
>  
>  /* serial port register map */
>  struct ioc3_serialregs {
> -	uint32_t	sscr;
> -	uint32_t	stpir;
> -	uint32_t	stcir;
> -	uint32_t	srpir;
> -	uint32_t	srcir;
> -	uint32_t	srtr;
> -	uint32_t	shadow;
> +	u32	sscr;
> +	u32	stpir;
> +	u32	stcir;
> +	u32	srpir;
> +	u32	srcir;
> +	u32	srtr;
> +	u32	shadow;
>  };
>  
>  /* SUPERIO uart register map */
>  struct ioc3_uartregs {
> +	u8	iu_lcr;
>  	union {
> -		char	rbr;	/* read only, DLAB == 0 */
> -		char	thr;	/* write only, DLAB == 0 */
> -		char	dll;	/* DLAB == 1 */
> -	} u1;
> +		u8	iir;	/* read only */
> +		u8	fcr;	/* write only */
> +	};
>  	union {
> -		char	ier;	/* DLAB == 0 */
> -		char	dlm;	/* DLAB == 1 */
> -	} u2;
> +		u8	ier;	/* DLAB == 0 */
> +		u8	dlm;	/* DLAB == 1 */
> +	};
>  	union {
> -		char	iir;	/* read only */
> -		char	fcr;	/* write only */
> -	} u3;
> -	char	iu_lcr;
> -	char	iu_mcr;
> -	char	iu_lsr;
> -	char	iu_msr;
> -	char	iu_scr;
> +		u8	rbr;	/* read only, DLAB == 0 */
> +		u8	thr;	/* write only, DLAB == 0 */
> +		u8	dll;	/* DLAB == 1 */
> +	} u1;
> +	u8	iu_scr;
> +	u8	iu_msr;
> +	u8	iu_lsr;
> +	u8	iu_mcr;
>  };
>  
>  #define iu_rbr u1.rbr
> @@ -50,122 +50,122 @@ struct ioc3_uartregs {
>  #define iu_fcr u3.fcr
>  
>  struct ioc3_sioregs {
> -	char	fill[0x141];	/* starts at 0x141 */
> +	u8	fill[0x141];	/* starts at 0x141 */
>  
> -	char	uartc;
> -	char	kbdcg;
> +	u8	kbdcg;
> +	u8	uartc;
>  
> -	char	fill0[0x150 - 0x142 - 1];
> +	u8	fill0[0x151 - 0x142 - 1];
>  
> -	char	pp_data;
> -	char	pp_dsr;
> -	char	pp_dcr;
> +	u8	pp_dcr;
> +	u8	pp_dsr;
> +	u8	pp_data;
>  
> -	char	fill1[0x158 - 0x152 - 1];
> +	u8	fill1[0x159 - 0x153 - 1];
>  
> -	char	pp_fifa;
> -	char	pp_cfgb;
> -	char	pp_ecr;
> +	u8	pp_ecr;
> +	u8	pp_cfgb;
> +	u8	pp_fifa;
>  
> -	char	fill2[0x168 - 0x15a - 1];
> +	u8	fill2[0x16a - 0x15b - 1];
>  
> -	char	rtcad;
> -	char	rtcdat;
> +	u8	rtcdat;
> +	u8	rtcad;
>  
> -	char	fill3[0x170 - 0x169 - 1];
> +	u8	fill3[0x170 - 0x16b - 1];
>  
>  	struct ioc3_uartregs	uartb;	/* 0x20170  */
>  	struct ioc3_uartregs	uarta;	/* 0x20178  */
>  };
>  
>  struct ioc3_ethregs {
> -	uint32_t	emcr;		/* 0x000f0  */
> -	uint32_t	eisr;		/* 0x000f4  */
> -	uint32_t	eier;		/* 0x000f8  */
> -	uint32_t	ercsr;		/* 0x000fc  */
> -	uint32_t	erbr_h;		/* 0x00100  */
> -	uint32_t	erbr_l;		/* 0x00104  */
> -	uint32_t	erbar;		/* 0x00108  */
> -	uint32_t	ercir;		/* 0x0010c  */
> -	uint32_t	erpir;		/* 0x00110  */
> -	uint32_t	ertr;		/* 0x00114  */
> -	uint32_t	etcsr;		/* 0x00118  */
> -	uint32_t	ersr;		/* 0x0011c  */
> -	uint32_t	etcdc;		/* 0x00120  */
> -	uint32_t	ebir;		/* 0x00124  */
> -	uint32_t	etbr_h;		/* 0x00128  */
> -	uint32_t	etbr_l;		/* 0x0012c  */
> -	uint32_t	etcir;		/* 0x00130  */
> -	uint32_t	etpir;		/* 0x00134  */
> -	uint32_t	emar_h;		/* 0x00138  */
> -	uint32_t	emar_l;		/* 0x0013c  */
> -	uint32_t	ehar_h;		/* 0x00140  */
> -	uint32_t	ehar_l;		/* 0x00144  */
> -	uint32_t	micr;		/* 0x00148  */
> -	uint32_t	midr_r;		/* 0x0014c  */
> -	uint32_t	midr_w;		/* 0x00150  */
> +	u32	emcr;		/* 0x000f0  */
> +	u32	eisr;		/* 0x000f4  */
> +	u32	eier;		/* 0x000f8  */
> +	u32	ercsr;		/* 0x000fc  */
> +	u32	erbr_h;		/* 0x00100  */
> +	u32	erbr_l;		/* 0x00104  */
> +	u32	erbar;		/* 0x00108  */
> +	u32	ercir;		/* 0x0010c  */
> +	u32	erpir;		/* 0x00110  */
> +	u32	ertr;		/* 0x00114  */
> +	u32	etcsr;		/* 0x00118  */
> +	u32	ersr;		/* 0x0011c  */
> +	u32	etcdc;		/* 0x00120  */
> +	u32	ebir;		/* 0x00124  */
> +	u32	etbr_h;		/* 0x00128  */
> +	u32	etbr_l;		/* 0x0012c  */
> +	u32	etcir;		/* 0x00130  */
> +	u32	etpir;		/* 0x00134  */
> +	u32	emar_h;		/* 0x00138  */
> +	u32	emar_l;		/* 0x0013c  */
> +	u32	ehar_h;		/* 0x00140  */
> +	u32	ehar_l;		/* 0x00144  */
> +	u32	micr;		/* 0x00148  */
> +	u32	midr_r;		/* 0x0014c  */
> +	u32	midr_w;		/* 0x00150  */
>  };
>  
>  struct ioc3_serioregs {
> -	uint32_t	km_csr;		/* 0x0009c  */
> -	uint32_t	k_rd;		/* 0x000a0  */
> -	uint32_t	m_rd;		/* 0x000a4  */
> -	uint32_t	k_wd;		/* 0x000a8  */
> -	uint32_t	m_wd;		/* 0x000ac  */
> +	u32	km_csr;		/* 0x0009c  */
> +	u32	k_rd;		/* 0x000a0  */
> +	u32	m_rd;		/* 0x000a4  */
> +	u32	k_wd;		/* 0x000a8  */
> +	u32	m_wd;		/* 0x000ac  */
>  };
>  
>  /* Register layout of IOC3 in configuration space.  */
>  struct ioc3 {
>  	/* PCI Config Space registers  */
> -	uint32_t	pci_id;		/* 0x00000  */
> -	uint32_t	pci_scr;	/* 0x00004  */
> -	uint32_t	pci_rev;	/* 0x00008  */
> -	uint32_t	pci_lat;	/* 0x0000c  */
> -	uint32_t	pci_addr;	/* 0x00010  */
> -	uint32_t	pci_err_addr_l;	/* 0x00014  */
> -	uint32_t	pci_err_addr_h;	/* 0x00018  */
> -
> -	uint32_t	sio_ir;		/* 0x0001c  */
> -	uint32_t	sio_ies;	/* 0x00020  */
> -	uint32_t	sio_iec;	/* 0x00024  */
> -	uint32_t	sio_cr;		/* 0x00028  */
> -	uint32_t	int_out;	/* 0x0002c  */
> -	uint32_t	mcr;		/* 0x00030  */
> +	u32	pci_id;		/* 0x00000  */
> +	u32	pci_scr;	/* 0x00004  */
> +	u32	pci_rev;	/* 0x00008  */
> +	u32	pci_lat;	/* 0x0000c  */
> +	u32	pci_addr;	/* 0x00010  */
> +	u32	pci_err_addr_l;	/* 0x00014  */
> +	u32	pci_err_addr_h;	/* 0x00018  */
> +
> +	u32	sio_ir;		/* 0x0001c  */
> +	u32	sio_ies;	/* 0x00020  */
> +	u32	sio_iec;	/* 0x00024  */
> +	u32	sio_cr;		/* 0x00028  */
> +	u32	int_out;	/* 0x0002c  */
> +	u32	mcr;		/* 0x00030  */
>  
>  	/* General Purpose I/O registers  */
> -	uint32_t	gpcr_s;		/* 0x00034  */
> -	uint32_t	gpcr_c;		/* 0x00038  */
> -	uint32_t	gpdr;		/* 0x0003c  */
> -	uint32_t	gppr[16];	/* 0x00040  */
> +	u32	gpcr_s;		/* 0x00034  */
> +	u32	gpcr_c;		/* 0x00038  */
> +	u32	gpdr;		/* 0x0003c  */
> +	u32	gppr[16];	/* 0x00040  */
>  
>  	/* Parallel Port Registers  */
> -	uint32_t	ppbr_h_a;	/* 0x00080  */
> -	uint32_t	ppbr_l_a;	/* 0x00084  */
> -	uint32_t	ppcr_a;		/* 0x00088  */
> -	uint32_t	ppcr;		/* 0x0008c  */
> -	uint32_t	ppbr_h_b;	/* 0x00090  */
> -	uint32_t	ppbr_l_b;	/* 0x00094  */
> -	uint32_t	ppcr_b;		/* 0x00098  */
> +	u32	ppbr_h_a;	/* 0x00080  */
> +	u32	ppbr_l_a;	/* 0x00084  */
> +	u32	ppcr_a;		/* 0x00088  */
> +	u32	ppcr;		/* 0x0008c  */
> +	u32	ppbr_h_b;	/* 0x00090  */
> +	u32	ppbr_l_b;	/* 0x00094  */
> +	u32	ppcr_b;		/* 0x00098  */
>  
>  	/* Keyboard and Mouse Registers	 */
>  	struct ioc3_serioregs	serio;
>  
>  	/* Serial Port Registers  */
> -	uint32_t	sbbr_h;		/* 0x000b0  */
> -	uint32_t	sbbr_l;		/* 0x000b4  */
> +	u32	sbbr_h;		/* 0x000b0  */
> +	u32	sbbr_l;		/* 0x000b4  */
>  	struct ioc3_serialregs	port_a;
>  	struct ioc3_serialregs	port_b;
>  
>  	/* Ethernet Registers */
>  	struct ioc3_ethregs	eth;
> -	uint32_t	pad1[(0x20000 - 0x00154) / 4];
> +	u32	pad1[(0x20000 - 0x00154) / 4];
>  
>  	/* SuperIO Registers  XXX */
>  	struct ioc3_sioregs	sregs;	/* 0x20000 */
> -	uint32_t	pad2[(0x40000 - 0x20180) / 4];
> +	u32	pad2[(0x40000 - 0x20180) / 4];
>  
>  	/* SSRAM Diagnostic Access */
> -	uint32_t	ssram[(0x80000 - 0x40000) / 4];
> +	u32	ssram[(0x80000 - 0x40000) / 4];
>  
>  	/* Bytebus device offsets
>  	   0x80000 -   Access to the generic devices selected with   DEV0
> @@ -598,8 +598,4 @@ struct ioc3_etxd {
>  
>  #define MIDR_DATA_MASK		0x0000ffff
>  
> -#if defined(CONFIG_SGI_IP27) || defined(CONFIG_SGI_IP30)
> -extern int bridge_alloc_irq(struct pci_dev *dev);
> -#endif
> -
>  #endif /* MIPS_SN_IOC3_H */
> diff --git a/arch/mips/sgi-ip27/ip27-console.c b/arch/mips/sgi-ip27/ip27-console.c
> index 6bdb48d41276..5886bee89d06 100644
> --- a/arch/mips/sgi-ip27/ip27-console.c
> +++ b/arch/mips/sgi-ip27/ip27-console.c
> @@ -35,6 +35,7 @@ void prom_putchar(char c)
>  {
>  	struct ioc3_uartregs *uart = console_uart();
>  
> -	while ((uart->iu_lsr & 0x20) == 0);
> -	uart->iu_thr = c;
> +	while ((readb(&uart->iu_lsr) & 0x20) == 0)
> +		;
> +	writeb(c, &uart->iu_thr);
>  }
> diff --git a/drivers/rtc/rtc-m48t35.c b/drivers/rtc/rtc-m48t35.c
> index 0cf6507de3c7..05f0d91366af 100644
> --- a/drivers/rtc/rtc-m48t35.c
> +++ b/drivers/rtc/rtc-m48t35.c
> @@ -24,6 +24,16 @@
>  
>  struct m48t35_rtc {
>  	u8	pad[0x7ff8];    /* starts at 0x7ff8 */
> +#ifdef CONFIG_SGI_IP27
> +	u8	hour;
> +	u8	min;
> +	u8	sec;
> +	u8	control;
> +	u8	year;
> +	u8	month;
> +	u8	date;
> +	u8	day;
> +#else
>  	u8	control;
>  	u8	sec;
>  	u8	min;
> @@ -32,6 +42,7 @@ struct m48t35_rtc {
>  	u8	date;
>  	u8	month;
>  	u8	year;
> +#endif
>  };
>  
>  #define M48T35_RTC_SET		0x80
> diff --git a/drivers/tty/serial/8250/8250_ioc3.c b/drivers/tty/serial/8250/8250_ioc3.c
> index 2be6ed2967e0..4c405f1b9c67 100644
> --- a/drivers/tty/serial/8250/8250_ioc3.c
> +++ b/drivers/tty/serial/8250/8250_ioc3.c
> @@ -23,12 +23,12 @@ struct ioc3_8250_data {
>  
>  static unsigned int ioc3_serial_in(struct uart_port *p, int offset)
>  {
> -	return readb(p->membase + offset);
> +	return readb(p->membase + (offset ^ 3));
>  }
>  
>  static void ioc3_serial_out(struct uart_port *p, int offset, int value)
>  {
> -	writeb(value, p->membase + offset);
> +	writeb(value, p->membase + (offset ^ 3));
>  }
>  
>  static int serial8250_ioc3_probe(struct platform_device *pdev)
> -- 
> 2.13.7
> 

-- 
Alexandre Belloni, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com