[PATCH 2/3 v3] tpm2: Add a TPMv2 MMIO TIS driver

[Heinrich Schuchardt]

On 08.07.21 10:23, Ilias Apalodimas wrote:
> Add support for devices that expose a TPMv2 though MMIO.
> Apart from those devices, we can use the driver in our QEMU setups and
> test TPM related code which is difficult to achieve using the sandbox
> driver (e.g test the EFI TCG2 protocol).
>
> It's worth noting that a previous patch added TPMv2 TIS core functions,
> which the current driver is consuming.
>
> Signed-off-by: Ilias Apalodimas <ilias.apalodimas at linaro.org>

There should be a defconfig using the driver to ensure that it is built
in CI. As you want to use the driver for testing with QEMU let that be
qemu_arm64_defconfig and qemu_arm_defconfig (we should build both 64bit
and 32bit).

A paragraph in doc/board/emulation/qemu-arm.rst indicating how to
emulate a TPM would be helpful.

I think information like the following is needed:

To emulate a TPM the swtpm package may be used. It can be built from the
following repositories:

     https://github.com/stefanberger/libtpms.git
     https://github.com/stefanberger/swtpm.git

Swtpm provides a socket for the TPM emulation which can be consumed by QEMU.

In a first console invoke swtpm:

     swtpm socket --tpmstate dir=/tmp/mytpm1   \
     --ctrl type=unixio,path=/tmp/mytpm1/swtpm-sock --log level=20

In a second console invoke qemu-system-aarch64 with

     -chardev socket,id=chrtpm,path=/tmp/mytpm1/swtpm-sock \
     -tpmdev emulator,id=tpm0,chardev=chrtpm \
     -device tpm-tis-device,tpmdev=tpm0

To use the TPM emulation U-Boot must be compiled with

???

Best regards

Heinrich

> ---
>   drivers/tpm/Kconfig         |   9 +++
>   drivers/tpm/Makefile        |   1 +
>   drivers/tpm/tpm2_tis_mmio.c | 156 ++++++++++++++++++++++++++++++++++++
>   3 files changed, 166 insertions(+)
>   create mode 100644 drivers/tpm/tpm2_tis_mmio.c
>
> diff --git a/drivers/tpm/Kconfig b/drivers/tpm/Kconfig
> index 9eebab5cfd90..406ee8716e1e 100644
> --- a/drivers/tpm/Kconfig
> +++ b/drivers/tpm/Kconfig
> @@ -161,6 +161,15 @@ config TPM2_FTPM_TEE
>   	help
>   	  This driver supports firmware TPM running in TEE.
>
> +config TPM2_MMIO
> +	bool "MMIO based TPM2 Interface"
> +	depends on TPM_V2
> +	help
> +	  This driver supports firmware TPM2.0 MMIO interface.
> +	  The usual TPM operations and the 'tpm' command can be used to talk
> +	  to the device using the standard TPM Interface Specification (TIS)
> +	  protocol.
> +
>   endif # TPM_V2
>
>   endmenu
> diff --git a/drivers/tpm/Makefile b/drivers/tpm/Makefile
> index f64d20067f88..1065c1874f58 100644
> --- a/drivers/tpm/Makefile
> +++ b/drivers/tpm/Makefile
> @@ -14,3 +14,4 @@ obj-$(CONFIG_$(SPL_TPL_)TPM2_CR50_I2C) += cr50_i2c.o
>   obj-$(CONFIG_TPM2_TIS_SANDBOX) += tpm2_tis_sandbox.o
>   obj-$(CONFIG_TPM2_TIS_SPI) += tpm2_tis_spi.o
>   obj-$(CONFIG_TPM2_FTPM_TEE) += tpm2_ftpm_tee.o
> +obj-$(CONFIG_TPM2_MMIO) += tpm2_tis_core.o tpm2_tis_mmio.o
> diff --git a/drivers/tpm/tpm2_tis_mmio.c b/drivers/tpm/tpm2_tis_mmio.c
> new file mode 100644
> index 000000000000..2183a2807162
> --- /dev/null
> +++ b/drivers/tpm/tpm2_tis_mmio.c
> @@ -0,0 +1,156 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * driver for mmio TCG/TIS TPM (trusted platform module).
> + *
> + * Specifications at www.trustedcomputinggroup.org
> + */
> +
> +#include <common.h>
> +#include <dm.h>
> +#include <log.h>
> +#include <tpm-v2.h>
> +#include <linux/bitops.h>
> +#include <linux/compiler.h>
> +#include <linux/delay.h>
> +#include <linux/errno.h>
> +#include <linux/types.h>
> +#include <linux/io.h>
> +#include <linux/unaligned/be_byteshift.h>
> +#include "tpm_tis.h"
> +#include "tpm_internal.h"
> +
> +struct tpm_tis_chip_data {
> +	unsigned int pcr_count;
> +	unsigned int pcr_select_min;
> +	unsigned int time_before_first_cmd_ms;
> +	void __iomem *iobase;
> +};
> +
> +static int mmio_read_bytes(struct udevice *udev, u32 addr, u16 len,
> +			   u8 *result)
> +{
> +	struct tpm_tis_chip_data *drv_data = (void *)dev_get_driver_data(udev);
> +
> +	while (len--)
> +		*result++ = ioread8(drv_data->iobase + addr);
> +	return 0;
> +}
> +
> +static int mmio_write_bytes(struct udevice *udev, u32 addr, u16 len,
> +			    const u8 *value)
> +{
> +	struct tpm_tis_chip_data *drv_data = (void *)dev_get_driver_data(udev);
> +
> +	while (len--)
> +		iowrite8(*value++, drv_data->iobase + addr);
> +	return 0;
> +}
> +
> +static int mmio_read16(struct udevice *udev, u32 addr, u16 *result)
> +{
> +	struct tpm_tis_chip_data *drv_data = (void *)dev_get_driver_data(udev);
> +
> +	*result = ioread16(drv_data->iobase + addr);
> +	return 0;
> +}
> +
> +static int mmio_read32(struct udevice *udev, u32 addr, u32 *result)
> +{
> +	struct tpm_tis_chip_data *drv_data = (void *)dev_get_driver_data(udev);
> +
> +	*result = ioread32(drv_data->iobase + addr);
> +	return 0;
> +}
> +
> +static int mmio_write32(struct udevice *udev, u32 addr, u32 value)
> +{
> +	struct tpm_tis_chip_data *drv_data = (void *)dev_get_driver_data(udev);
> +
> +	iowrite32(value, drv_data->iobase + addr);
> +	return 0;
> +}
> +
> +static struct tpm_tis_phy_ops phy_ops = {
> +	.read_bytes = mmio_read_bytes,
> +	.write_bytes = mmio_write_bytes,
> +	.read16 = mmio_read16,
> +	.read32 = mmio_read32,
> +	.write32 = mmio_write32,
> +};
> +
> +static int tpm_tis_probe(struct udevice *udev)
> +{
> +	struct tpm_tis_chip_data *drv_data = (void *)dev_get_driver_data(udev);
> +	struct tpm_chip_priv *priv = dev_get_uclass_priv(udev);
> +	int ret = 0;
> +	fdt_addr_t ioaddr;
> +	u64 sz;
> +
> +	ioaddr = dev_read_addr(udev);
> +	if (ioaddr == FDT_ADDR_T_NONE)
> +		return -EINVAL;
> +
> +	ret = dev_read_u64(udev, "reg", &sz);
> +	if (ret)
> +		return -EINVAL;
> +
> +	drv_data->iobase = ioremap(ioaddr, sz);
> +	log_info("Remapped TPM2 base: 0x%llx size: 0x%llx\n", ioaddr, sz);
> +	tpm_tis_ops_register(udev, &phy_ops);
> +	ret = tpm_tis_init(udev);
> +	if (ret)
> +		goto iounmap;
> +
> +	priv->pcr_count = drv_data->pcr_count;
> +	priv->pcr_select_min = drv_data->pcr_select_min;
> +	/*
> +	 * Although the driver probably works with a TPMv1 our Kconfig
> +	 * limits the driver to TPMv2 only
> +	 */
> +	priv->version = TPM_V2;
> +
> +	return ret;
> +iounmap:
> +	iounmap(drv_data->iobase);
> +	return -EINVAL;
> +}
> +
> +static int tpm_tis_remove(struct udevice *udev)
> +{
> +	struct tpm_tis_chip_data *drv_data = (void *)dev_get_driver_data(udev);
> +
> +	iounmap(drv_data->iobase);
> +	return tpm_tis_cleanup(udev);
> +}
> +
> +static const struct tpm_ops tpm_tis_ops = {
> +	.open		= tpm_tis_open,
> +	.close		= tpm_tis_close,
> +	.get_desc	= tpm_tis_get_desc,
> +	.send		= tpm_tis_send,
> +	.recv		= tpm_tis_recv,
> +	.cleanup	= tpm_tis_cleanup,
> +};
> +
> +static const struct tpm_tis_chip_data tpm_tis_std_chip_data = {
> +	.pcr_count = 24,
> +	.pcr_select_min = 3,
> +};
> +
> +static const struct udevice_id tpm_tis_ids[] = {
> +	{
> +		.compatible = "tcg,tpm-tis-mmio",
> +		.data = (ulong)&tpm_tis_std_chip_data,
> +	},
> +	{ }
> +};
> +
> +U_BOOT_DRIVER(tpm_tis_mmio) = {
> +	.name   = "tpm_tis_mmio",
> +	.id     = UCLASS_TPM,
> +	.of_match = tpm_tis_ids,
> +	.ops    = &tpm_tis_ops,
> +	.probe	= tpm_tis_probe,
> +	.remove	= tpm_tis_remove,
> +	.priv_auto	= sizeof(struct tpm_chip),
> +};
>