skylake: Add function to set PRR for protecting flash
Add a function similar to broadwell to set the PRR for a region of flash and protect it from writes. This is used to secure the MRC cache region if the SPI is write protected. BUG=chrome-os-partner:54003 BRANCH=glados TEST=boot on chell, verify PRR register is set and that the MRC cache region cannot be written if the SPI is write protected. Change-Id: I925ec9ce186f7adac327bca9c96255325b7f54ec Signed-off-by: Duncan Laurie <dlaurie@chromium.org> Original-Commit-Id: abb6f645f5ceef3f52bb7afd2632212ea916ff8d Original-Change-Id: I2f90556a217b35b7c93645e41a1fcfe8070c53da Original-Signed-off-by: Duncan Laurie <dlaurie@chromium.org> Original-Reviewed-on: https://chromium-review.googlesource.com/349274 Original-Reviewed-by: Shawn N <shawnn@chromium.org> Original-Reviewed-by: Aaron Durbin <adurbin@chromium.org> Original-Tested-by: Shawn N <shawnn@chromium.org> Reviewed-on: https://review.coreboot.org/15102 Tested-by: build bot (Jenkins) Reviewed-by: Aaron Durbin <adurbin@chromium.org> Reviewed-by: Leroy P Leahy <leroy.p.leahy@intel.com> Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
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@ -386,6 +386,43 @@ struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs)
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return slave;
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}
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int spi_flash_protect(u32 start, u32 size)
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{
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pch_spi_regs *spi_bar = get_spi_bar();
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u32 end = start + size - 1;
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u32 reg;
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int prr;
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if (!spi_bar)
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return -1;
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/* Find first empty PRR */
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for (prr = 0; prr < SPI_PRR_MAX; prr++) {
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reg = read32(&spi_bar->pr[prr]);
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if (reg == 0)
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break;
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}
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if (prr >= SPI_PRR_MAX) {
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printk(BIOS_ERR, "ERROR: No SPI PRR free!\n");
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return -1;
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}
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/* Set protected range base and limit */
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reg = SPI_PRR(start, end) | SPI_PRR_WPE;
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/* Set the PRR register and verify it is protected */
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write32(&spi_bar->pr[prr], reg);
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reg = read32(&spi_bar->pr[prr]);
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if (!(reg & SPI_PRR_WPE)) {
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printk(BIOS_ERR, "ERROR: Unable to set SPI PRR %d\n", prr);
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return -1;
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}
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printk(BIOS_INFO, "%s: PRR %d is enabled for range 0x%08x-0x%08x\n",
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__func__, prr, start, end);
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return 0;
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}
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#if ENV_RAMSTAGE
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/*
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* spi_init() needs run unconditionally in every boot (including resume) to
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