Re: [PATCH] tpm: atmel: Drop PPC64 specific MMIO setup

[Jarkko Sakkinen]

On Wed Jul 17, 2024 at 3:08 PM EEST, Jarkko Sakkinen wrote:
> On Tue Jul 2, 2024 at 7:10 PM EEST, Rob Herring (Arm) wrote:
> > The PPC64 specific MMIO setup open codes DT address functions rather
> > than using standard address parsing functions. The open-coded version
> > fails to handle any address translation and is not endian safe.
> >
> > I haven't found any evidence of what platform used this. The only thing
> > that turned up was a PPC405 platform, but that is 32-bit and PPC405
> > support is being removed as well. CONFIG_TCG_ATMEL is not enabled for
> > any powerpc config and never was. The support was added in 2005 and
> > hasn't been touched since.
> >
> > Rather than try to modernize and fix this code, just remove it.
> >
> > Signed-off-by: Rob Herring (Arm) <robh@xxxxxxxxxx>
> > ---
> >  drivers/char/tpm/Kconfig     |   2 +-
> >  drivers/char/tpm/tpm_atmel.c |  64 +++++++++++++++-
> >  drivers/char/tpm/tpm_atmel.h | 140 -----------------------------------
> >  3 files changed, 62 insertions(+), 144 deletions(-)
> >  delete mode 100644 drivers/char/tpm/tpm_atmel.h
> >
> > diff --git a/drivers/char/tpm/Kconfig b/drivers/char/tpm/Kconfig
> > index e63a6a17793c..9b655e9fc7ab 100644
> > --- a/drivers/char/tpm/Kconfig
> > +++ b/drivers/char/tpm/Kconfig
> > @@ -162,7 +162,7 @@ config TCG_NSC
> >  
> >  config TCG_ATMEL
> >  	tristate "Atmel TPM Interface"
> > -	depends on PPC64 || HAS_IOPORT_MAP
> > +	depends on HAS_IOPORT_MAP
> >  	depends on HAS_IOPORT
> >  	help
> >  	  If you have a TPM security chip from Atmel say Yes and it 
> > diff --git a/drivers/char/tpm/tpm_atmel.c b/drivers/char/tpm/tpm_atmel.c
> > index 9fb2defa9dc4..622c4abe8cb3 100644
> > --- a/drivers/char/tpm/tpm_atmel.c
> > +++ b/drivers/char/tpm/tpm_atmel.c
> > @@ -15,7 +15,67 @@
> >   */
> >  
> >  #include "tpm.h"
> > -#include "tpm_atmel.h"
> > +
> > +struct tpm_atmel_priv {
> > +	int region_size;
> > +	int have_region;
> > +	unsigned long base;
> > +	void __iomem *iobase;
> > +};
> > +
> > +#define atmel_getb(chip, offset) inb(atmel_get_priv(chip)->base + offset)
> > +#define atmel_putb(val, chip, offset) \
> > +	outb(val, atmel_get_priv(chip)->base + offset)
> > +#define atmel_request_region request_region
> > +#define atmel_release_region release_region
> > +/* Atmel definitions */
> > +enum tpm_atmel_addr {
> > +	TPM_ATMEL_BASE_ADDR_LO = 0x08,
> > +	TPM_ATMEL_BASE_ADDR_HI = 0x09
> > +};
> > +
> > +static inline int tpm_read_index(int base, int index)
> > +{
> > +	outb(index, base);
> > +	return inb(base+1) & 0xFF;
> > +}
> > +
> > +/* Verify this is a 1.1 Atmel TPM */
> > +static int atmel_verify_tpm11(void)
> > +{
> > +
> > +	/* verify that it is an Atmel part */
> > +	if (tpm_read_index(TPM_ADDR, 4) != 'A' ||
> > +	    tpm_read_index(TPM_ADDR, 5) != 'T' ||
> > +	    tpm_read_index(TPM_ADDR, 6) != 'M' ||
> > +	    tpm_read_index(TPM_ADDR, 7) != 'L')
> > +		return 1;
> > +
> > +	/* query chip for its version number */
> > +	if (tpm_read_index(TPM_ADDR, 0x00) != 1 ||
> > +	    tpm_read_index(TPM_ADDR, 0x01) != 1)
> > +		return 1;
> > +
> > +	/* This is an atmel supported part */
> > +	return 0;
> > +}
> > +
> > +/* Determine where to talk to device */
> > +static void __iomem * atmel_get_base_addr(unsigned long *base, int *region_size)
> > +{
> > +	int lo, hi;
> > +
> > +	if (atmel_verify_tpm11() != 0)
> > +		return NULL;
> > +
> > +	lo = tpm_read_index(TPM_ADDR, TPM_ATMEL_BASE_ADDR_LO);
> > +	hi = tpm_read_index(TPM_ADDR, TPM_ATMEL_BASE_ADDR_HI);
> > +
> > +	*base = (hi << 8) | lo;
> > +	*region_size = 2;
> > +
> > +	return ioport_map(*base, *region_size);
> > +}
> >  
> >  /* write status bits */
> >  enum tpm_atmel_write_status {
> > @@ -142,7 +202,6 @@ static void atml_plat_remove(void)
> >  	tpm_chip_unregister(chip);
> >  	if (priv->have_region)
> >  		atmel_release_region(priv->base, priv->region_size);
> > -	atmel_put_base_addr(priv->iobase);
> >  	platform_device_unregister(pdev);
> >  }
> >  
> > @@ -211,7 +270,6 @@ static int __init init_atmel(void)
> >  err_unreg_dev:
> >  	platform_device_unregister(pdev);
> >  err_rel_reg:
> > -	atmel_put_base_addr(iobase);
> >  	if (have_region)
> >  		atmel_release_region(base,
> >  				     region_size);
> > diff --git a/drivers/char/tpm/tpm_atmel.h b/drivers/char/tpm/tpm_atmel.h
> > deleted file mode 100644
> > index 7ac3f69dcf0f..000000000000
> > --- a/drivers/char/tpm/tpm_atmel.h
> > +++ /dev/null
> > @@ -1,140 +0,0 @@
> > -/* SPDX-License-Identifier: GPL-2.0-only */
> > -/*
> > - * Copyright (C) 2005 IBM Corporation
> > - *
> > - * Authors:
> > - * Kylene Hall <kjhall@xxxxxxxxxx>
> > - *
> > - * Maintained by: <tpmdd-devel@xxxxxxxxxxxxxxxxxxxxx>
> > - *
> > - * Device driver for TCG/TCPA TPM (trusted platform module).
> > - * Specifications at www.trustedcomputinggroup.org
> > - *
> > - * These difference are required on power because the device must be
> > - * discovered through the device tree and iomap must be used to get
> > - * around the need for holes in the io_page_mask.  This does not happen
> > - * automatically because the tpm is not a normal pci device and lives
> > - * under the root node.
> > - */
> > -
> > -struct tpm_atmel_priv {
> > -	int region_size;
> > -	int have_region;
> > -	unsigned long base;
> > -	void __iomem *iobase;
> > -};
> > -
> > -#ifdef CONFIG_PPC64
> > -
> > -#include <linux/of.h>
> > -
> > -#define atmel_getb(priv, offset) readb(priv->iobase + offset)
> > -#define atmel_putb(val, priv, offset) writeb(val, priv->iobase + offset)
> > -#define atmel_request_region request_mem_region
> > -#define atmel_release_region release_mem_region
> > -
> > -static inline void atmel_put_base_addr(void __iomem *iobase)
> > -{
> > -	iounmap(iobase);
> > -}
> > -
> > -static void __iomem * atmel_get_base_addr(unsigned long *base, int *region_size)
> > -{
> > -	struct device_node *dn;
> > -	unsigned long address, size;
> > -	const unsigned int *reg;
> > -	int reglen;
> > -	int naddrc;
> > -	int nsizec;
> > -
> > -	dn = of_find_node_by_name(NULL, "tpm");
> > -
> > -	if (!dn)
> > -		return NULL;
> > -
> > -	if (!of_device_is_compatible(dn, "AT97SC3201")) {
> > -		of_node_put(dn);
> > -		return NULL;
> > -	}
> > -
> > -	reg = of_get_property(dn, "reg", &reglen);
> > -	naddrc = of_n_addr_cells(dn);
> > -	nsizec = of_n_size_cells(dn);
> > -
> > -	of_node_put(dn);
> > -
> > -
> > -	if (naddrc == 2)
> > -		address = ((unsigned long) reg[0] << 32) | reg[1];
> > -	else
> > -		address = reg[0];
> > -
> > -	if (nsizec == 2)
> > -		size =
> > -		    ((unsigned long) reg[naddrc] << 32) | reg[naddrc + 1];
> > -	else
> > -		size = reg[naddrc];
> > -
> > -	*base = address;
> > -	*region_size = size;
> > -	return ioremap(*base, *region_size);
> > -}
> > -#else
> > -#define atmel_getb(chip, offset) inb(atmel_get_priv(chip)->base + offset)
> > -#define atmel_putb(val, chip, offset) \
> > -	outb(val, atmel_get_priv(chip)->base + offset)
> > -#define atmel_request_region request_region
> > -#define atmel_release_region release_region
> > -/* Atmel definitions */
> > -enum tpm_atmel_addr {
> > -	TPM_ATMEL_BASE_ADDR_LO = 0x08,
> > -	TPM_ATMEL_BASE_ADDR_HI = 0x09
> > -};
> > -
> > -static inline int tpm_read_index(int base, int index)
> > -{
> > -	outb(index, base);
> > -	return inb(base+1) & 0xFF;
> > -}
> > -
> > -/* Verify this is a 1.1 Atmel TPM */
> > -static int atmel_verify_tpm11(void)
> > -{
> > -
> > -	/* verify that it is an Atmel part */
> > -	if (tpm_read_index(TPM_ADDR, 4) != 'A' ||
> > -	    tpm_read_index(TPM_ADDR, 5) != 'T' ||
> > -	    tpm_read_index(TPM_ADDR, 6) != 'M' ||
> > -	    tpm_read_index(TPM_ADDR, 7) != 'L')
> > -		return 1;
> > -
> > -	/* query chip for its version number */
> > -	if (tpm_read_index(TPM_ADDR, 0x00) != 1 ||
> > -	    tpm_read_index(TPM_ADDR, 0x01) != 1)
> > -		return 1;
> > -
> > -	/* This is an atmel supported part */
> > -	return 0;
> > -}
> > -
> > -static inline void atmel_put_base_addr(void __iomem *iobase)
> > -{
> > -}
> > -
> > -/* Determine where to talk to device */
> > -static void __iomem * atmel_get_base_addr(unsigned long *base, int *region_size)
> > -{
> > -	int lo, hi;
> > -
> > -	if (atmel_verify_tpm11() != 0)
> > -		return NULL;
> > -
> > -	lo = tpm_read_index(TPM_ADDR, TPM_ATMEL_BASE_ADDR_LO);
> > -	hi = tpm_read_index(TPM_ADDR, TPM_ATMEL_BASE_ADDR_HI);
> > -
> > -	*base = (hi << 8) | lo;
> > -	*region_size = 2;
> > -
> > -	return ioport_map(*base, *region_size);
> > -}
> > -#endif
>
> Responding from holidays but:
>
> Reviewed-by: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
>
> [still away for couple of weeks]

I got these in with checkpatch.pl --strict:

CHECK: Macro argument 'offset' may be better as '(offset)' to avoid precedence issues
#59: FILE: drivers/char/tpm/tpm_atmel.c:26:
+#define atmel_getb(chip, offset) inb(atmel_get_priv(chip)->base + offset)

CHECK: Macro argument 'offset' may be better as '(offset)' to avoid precedence issues
#60: FILE: drivers/char/tpm/tpm_atmel.c:27:
+#define atmel_putb(val, chip, offset) \
+	outb(val, atmel_get_priv(chip)->base + offset)

CHECK: spaces preferred around that '+' (ctx:VxV)
#73: FILE: drivers/char/tpm/tpm_atmel.c:40:
+	return inb(base+1) & 0xFF;
 	              ^

CHECK: Blank lines aren't necessary after an open brace '{'
#79: FILE: drivers/char/tpm/tpm_atmel.c:46:
+{
+

Can you address them and I'll tag the next version, once I've
revisited checkpatch. Otherwise, nothing against the code change.

BR, Jarkko