RE: [PATCH v4] tpm: Enable CLKRUN protocol for Braswell systems

[Shaikh, Azhar]

> -----Original Message-----
> From: Jarkko Sakkinen [mailto:jarkko.sakkinen@xxxxxxxxxxxxxxx]
> Sent: Sunday, June 18, 2017 4:53 PM
> To: Shaikh, Azhar <azhar.shaikh@xxxxxxxxx>;
> jgunthorpe@xxxxxxxxxxxxxxxxxxxx; tpmdd-devel@xxxxxxxxxxxxxxxxxxxxx;
> linux-kernel@xxxxxxxxxxxxxxx
> Cc: linux-security-module@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH v4] tpm: Enable CLKRUN protocol for Braswell systems
> 
> On Wed, 2017-06-14 at 12:39 -0700, Azhar Shaikh wrote:
> > To overcome a hardware limitation on Intel Braswell systems, disable
> > CLKRUN protocol during TPM transactions and re-enable once the
> > transaction is completed.
> >
> > Signed-off-by: Azhar Shaikh <azhar.shaikh@xxxxxxxxx>
> 
> Does not merge to my tree:
> 
> git://git.infradead.org/users/jjs/linux-tpmdd.git
> 
> Please fix.
> 

Sure will rebase and send again.

> /Jarkko
> 
> > ---
> > Changes from v1:
> > - Add CONFIG_X86 around disable_lpc_clk_run() and enable_lpc_clk_run()
> > to avoid
> > - build breakage on architectures which do not implement
> > kmap_atomic_pfn()
> >
> > Changes from v2:
> > - Use ioremap()/iounmap() instead of
> kmap_atomic_pfn()/kunmap_atomic()
> > - Move is_bsw() and all macros from tpm.h to tpm_tis.c file.
> > - Add the is_bsw() check in disable_lpc_clk_run() and
> > enable_lpc_clk_run()
> > - instead of adding it in each read/write API.
> >
> > Changes from v3:
> > - Move the code under #ifdef CONFIG_X86 and create stub functions for
> > everything else
> > - Rename the functions disable_lpc_clk_run() ->
> > tpm_platform_begin_xfer() and
> > - enable_lpc_clk_run() -> tpm_platform_end_xfer()
> > - Remove wmb()
> > - Correct the parameters for outb()
> >
> >  drivers/char/tpm/tpm.h     |   4 ++
> >  drivers/char/tpm/tpm_tis.c | 112
> > +++++++++++++++++++++++++++++++++++++++++++++
> >  2 files changed, 116 insertions(+)
> >
> > diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h index
> > 4b4c8dee3096..6b769fbc4407 100644
> > --- a/drivers/char/tpm/tpm.h
> > +++ b/drivers/char/tpm/tpm.h
> > @@ -36,6 +36,10 @@
> >  #include <linux/highmem.h>
> >  #include <crypto/hash_info.h>
> >
> > +#ifdef CONFIG_X86
> > +#include <asm/intel-family.h>
> > +#endif
> > +
> >  enum tpm_const {
> >  	TPM_MINOR = 224,	/* officially assigned */
> >  	TPM_BUFSIZE = 4096,
> > diff --git a/drivers/char/tpm/tpm_tis.c b/drivers/char/tpm/tpm_tis.c
> > index c7e1384f1b08..ce6f1a8b0510 100644
> > --- a/drivers/char/tpm/tpm_tis.c
> > +++ b/drivers/char/tpm/tpm_tis.c
> > @@ -89,13 +89,93 @@ static inline int is_itpm(struct acpi_device *dev)
> > }  #endif
> >
> > +#ifdef CONFIG_X86
> > +#define INTEL_LEGACY_BLK_BASE_ADDR      0xFED08000
> > +#define ILB_REMAP_SIZE			0x100
> > +#define LPC_CNTRL_REG_OFFSET            0x84
> > +#define LPC_CLKRUN_EN                   (1 << 2)
> > +
> > +void __iomem *ilb_base_addr;
> > +
> > +static inline bool is_bsw(void)
> > +{
> > +	return ((boot_cpu_data.x86_model ==
> INTEL_FAM6_ATOM_AIRMONT) ? 1 :
> > +0); }
> > +
> > +/**
> > + * tpm_platform_begin_xfer() - clear LPC CLKRUN_EN i.e. clocks will
> > +be running  */ static void tpm_platform_begin_xfer(void) {
> > +	u32 clkrun_val;
> > +
> > +	if (!is_bsw())
> > +		return;
> > +
> > +	clkrun_val = ioread32(ilb_base_addr + LPC_CNTRL_REG_OFFSET);
> > +
> > +	/* Disable LPC CLKRUN# */
> > +	clkrun_val &= ~LPC_CLKRUN_EN;
> > +	iowrite32(clkrun_val, ilb_base_addr + LPC_CNTRL_REG_OFFSET);
> > +
> > +	/*
> > +	 * Write any random value on port 0x80 which is on LPC, to make
> > +	 * sure LPC clock is running before sending any TPM command.
> > +	 */
> > +	outb(0xCC, 0x80);
> > +
> > +}
> > +
> > +/**
> > + * tpm_platform_end_xfer() - set LPC CLKRUN_EN i.e. clocks can be
> > +turned off  */ static void tpm_platform_end_xfer(void) {
> > +	u32 clkrun_val;
> > +
> > +	if (!is_bsw())
> > +		return;
> > +
> > +	clkrun_val = ioread32(ilb_base_addr + LPC_CNTRL_REG_OFFSET);
> > +
> > +	/* Enable LPC CLKRUN# */
> > +	clkrun_val |= LPC_CLKRUN_EN;
> > +	iowrite32(clkrun_val, ilb_base_addr + LPC_CNTRL_REG_OFFSET);
> > +
> > +	/*
> > +	 * Write any random value on port 0x80 which is on LPC, to make
> > +	 * sure LPC clock is running before sending any TPM command.
> > +	 */
> > +	outb(0xCC, 0x80);
> > +
> > +}
> > +#else
> > +static inline bool is_bsw(void)
> > +{
> > +	return false;
> > +}
> > +
> > +static void tpm_platform_begin_xfer(void) { }
> > +
> > +static void tpm_platform_end_xfer(void) { } #endif
> > +
> >  static int tpm_tcg_read_bytes(struct tpm_tis_data *data, u32 addr, u16
> len,
> >  			      u8 *result)
> >  {
> >  	struct tpm_tis_tcg_phy *phy = to_tpm_tis_tcg_phy(data);
> >
> > +	tpm_platform_begin_xfer();
> > +
> >  	while (len--)
> >  		*result++ = ioread8(phy->iobase + addr);
> > +
> > +	tpm_platform_end_xfer();
> > +
> >  	return 0;
> >  }
> >
> > @@ -104,8 +184,13 @@ static int tpm_tcg_write_bytes(struct
> > tpm_tis_data *data, u32 addr, u16 len,  {
> >  	struct tpm_tis_tcg_phy *phy = to_tpm_tis_tcg_phy(data);
> >
> > +	tpm_platform_begin_xfer();
> > +
> >  	while (len--)
> >  		iowrite8(*value++, phy->iobase + addr);
> > +
> > +	tpm_platform_end_xfer();
> > +
> >  	return 0;
> >  }
> >
> > @@ -113,7 +198,12 @@ static int tpm_tcg_read16(struct tpm_tis_data
> > *data, u32 addr, u16 *result)  {
> >  	struct tpm_tis_tcg_phy *phy = to_tpm_tis_tcg_phy(data);
> >
> > +	tpm_platform_begin_xfer();
> > +
> >  	*result = ioread16(phy->iobase + addr);
> > +
> > +	tpm_platform_end_xfer();
> > +
> >  	return 0;
> >  }
> >
> > @@ -121,7 +211,12 @@ static int tpm_tcg_read32(struct tpm_tis_data
> > *data, u32 addr, u32 *result)  {
> >  	struct tpm_tis_tcg_phy *phy = to_tpm_tis_tcg_phy(data);
> >
> > +	tpm_platform_begin_xfer();
> > +
> >  	*result = ioread32(phy->iobase + addr);
> > +
> > +	tpm_platform_end_xfer();
> > +
> >  	return 0;
> >  }
> >
> > @@ -129,7 +224,12 @@ static int tpm_tcg_write32(struct tpm_tis_data
> > *data, u32 addr, u32 value)  {
> >  	struct tpm_tis_tcg_phy *phy = to_tpm_tis_tcg_phy(data);
> >
> > +	tpm_platform_begin_xfer();
> > +
> >  	iowrite32(value, phy->iobase + addr);
> > +
> > +	tpm_platform_end_xfer();
> > +
> >  	return 0;
> >  }
> >
> > @@ -191,6 +291,12 @@ static int tpm_tis_pnp_init(struct pnp_dev
> *pnp_dev,
> >  		acpi_dev_handle = ACPI_HANDLE(&pnp_dev->dev);
> >  	}
> >
> > +#ifdef CONFIG_X86
> > +	if (is_bsw())
> > +		ilb_base_addr = ioremap(INTEL_LEGACY_BLK_BASE_ADDR,
> > +					ILB_REMAP_SIZE);
> > +#endif
> > +
> >  	return tpm_tis_init(&pnp_dev->dev, &tpm_info, acpi_dev_handle);
> }
> >
> > @@ -214,6 +320,12 @@ static void tpm_tis_pnp_remove(struct pnp_dev
> > *dev)
> >
> >  	tpm_chip_unregister(chip);
> >  	tpm_tis_remove(chip);
> > +
> > +#ifdef CONFIG_X86
> > +	if (is_bsw())
> > +		iounmap(ilb_base_addr);
> > +#endif
> > +
> >  }
> >
> >  static struct pnp_driver tis_pnp_driver = {