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.sha...@intel.com>
---
drivers/char/tpm/tpm.h | 20 +++++++++++
drivers/char/tpm/tpm_tis.c | 85 ++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 105 insertions(+)
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 4b4c8dee3096..98032a22317e 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,
@@ -436,6 +440,22 @@ struct tpm_buf {
u8 *data;
};
+#define INTEL_LEGACY_BLK_BASE_ADDR 0xFED08000
+#define LPC_CNTRL_REG_OFFSET 0x84
+#define LPC_CLKRUN_EN (1 << 2)
+
+#ifdef CONFIG_X86
+static inline bool is_bsw(void)
+{
+ return ((boot_cpu_data.x86_model == INTEL_FAM6_ATOM_AIRMONT) ? 1 : 0);
+}
+#else
+static inline bool is_bsw(void)
+{
+ return false;
+}
+#endif
+
static inline int tpm_buf_init(struct tpm_buf *buf, u16 tag, u32 ordinal)
{
struct tpm_input_header *head;
diff --git a/drivers/char/tpm/tpm_tis.c b/drivers/char/tpm/tpm_tis.c
index c7e1384f1b08..25ead56382c0 100644
--- a/drivers/char/tpm/tpm_tis.c
+++ b/drivers/char/tpm/tpm_tis.c
@@ -89,13 +89,70 @@ static inline int is_itpm(struct acpi_device *dev)
}
#endif
+/**
+ * disable_lpc_clk_run() - clear LPC CLKRUN_EN i.e. clocks will be free running
+ */
+static void disable_lpc_clk_run(void)
+{
+ u32 clkrun_val;
+ void __iomem *ilb_base_addr = NULL;
+
+ ilb_base_addr = (void __iomem *)
+ kmap_atomic_pfn(INTEL_LEGACY_BLK_BASE_ADDR >> PAGE_SHIFT);
+
+ 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);
+
+ kunmap_atomic(ilb_base_addr);
+ /*
+ * Write any random value on port 0x80 which is on LPC, to make
+ * sure LPC clock is running before sending any TPM command.
+ */
+ outb(0x80, 0xCC);
+}
+
+/**
+ * enable_lpc_clk_run() - set LPC CLKRUN_EN i.e. clocks can be turned off
+ */
+static void enable_lpc_clk_run(void)
+{
+ u32 clkrun_val;
+ void __iomem *ilb_base_addr = NULL;
+
+ ilb_base_addr = (void __iomem *)
+ kmap_atomic_pfn(INTEL_LEGACY_BLK_BASE_ADDR >> PAGE_SHIFT);
+
+ 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);
+
+ kunmap_atomic(ilb_base_addr);
+ /*
+ * Write any random value on port 0x80 which is on LPC, to make
+ * sure LPC clock is running before sending any TPM command.
+ */
+ outb(0x80, 0xCC);
+}
+
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);
+ if (is_bsw())
+ disable_lpc_clk_run();
+
while (len--)
*result++ = ioread8(phy->iobase + addr);
+
+ if (is_bsw())
+ enable_lpc_clk_run();
+
return 0;
}
@@ -104,8 +161,15 @@ 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);
+ if (is_bsw())
+ disable_lpc_clk_run();
+
while (len--)
iowrite8(*value++, phy->iobase + addr);
+
+ if (is_bsw())
+ enable_lpc_clk_run();
+
return 0;
}
@@ -113,7 +177,14 @@ 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);
+ if (is_bsw())
+ disable_lpc_clk_run();
+
*result = ioread16(phy->iobase + addr);
+
+ if (is_bsw())
+ enable_lpc_clk_run();
+
return 0;
}
@@ -121,7 +192,14 @@ 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);
+ if (is_bsw())
+ disable_lpc_clk_run();
+
*result = ioread32(phy->iobase + addr);
+
+ if (is_bsw())
+ enable_lpc_clk_run();
+
return 0;
}
@@ -129,7 +207,14 @@ 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);
+ if (is_bsw())
+ disable_lpc_clk_run();
+
iowrite32(value, phy->iobase + addr);
+
+ if (is_bsw())
+ enable_lpc_clk_run();
+
return 0;
}
--
1.9.1
