Re: [PATCH v5] tpm: Enable CLKRUN protocol for Braswell systems

[Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>]

On Sun, Jun 18, 2017 at 07:17:59PM -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@intel.com>

Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> (compilation)

/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()
> 
> Changes from v4:
> - Rebased to apply on git://git.infradead.org/users/jjs/linux-tpmdd.git
> 
>  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 1df0521138d3..cdd261383dea 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 b14d4aa97af8..506e62ca3576 100644
> --- a/drivers/char/tpm/tpm_tis.c
> +++ b/drivers/char/tpm/tpm_tis.c
> @@ -132,13 +132,93 @@ static int check_acpi_tpm2(struct 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;
>  }
>  
> @@ -147,8 +227,13 @@ 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;
>  }
>  
> @@ -156,7 +241,12 @@ 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;
>  }
>  
> @@ -164,7 +254,12 @@ 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;
>  }
>  
> @@ -172,7 +267,12 @@ 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;
>  }
>  
> @@ -230,6 +330,12 @@ static int tpm_tis_pnp_init(struct pnp_dev *pnp_dev,
>  	else
>  		tpm_info.irq = -1;
>  
> +#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);
>  }
>  
> @@ -253,6 +359,12 @@ 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 = {
> -- 
> 1.9.1
>